ADCIRCWiki - User contributions [en]

Fort.22 file

2024-10-04T17:33:56Z

Jddratli:

A single meteorological input file (wind velocity and atmospheric pressure) is read when meteorological forcing has been indicated by the <code>[[NWS]]</code> parameter in the [[fort.15 file]]. More precisely, the format of and need for the fort.22 file depend on the ones and tens (i.e. the last 2) digits and the sign (positive/negative) of <code>NWS</code> (see [[NWS#Value_Seen_in_fort.15_File|here]]). See also the [[supplemental meteorological/wave/ice parameters]] and [[wind stress]] pages.

== General Notes ==
Unless otherwise specified for a given format, ADCIRC expects wind data to represent [[Wind_Stress#Definition_of_Winds|specific conditions]] and pressure data to be sea level pressure. Where necessary, ADCIRC assumes a "background" atmospheric pressure of 1013 millibars.

Meteorological data in most formats must be provided for the entire model run, otherwise the run will crash. Exceptions include OWI (<code>NWS=12</code>) and GFDL (<code>NWS=16</code>).

For most formats, latitude and longitude coordinates describing the spatial extents of the meteorological data must follow the convention of the ADCIRC model domain. For example, if the [[fort.14 file|mesh]] uses negative longitude values to indicate locations West of the Greenwich meridian, the meteorological file must be similarly organized. Any grid that crosses the Greenwich Meridian should be organized so that the seam occurs at 180 deg longitude. Therefore, the meteorological and ADCIRC grids should use negative longitudes West of the Greenwich Meridian and positive longitudes to the East.

== File Format ==
The remainder of this page is devoted to the formats of the fort.22 file for the different values of <code>NWS</code>. Each line of input data is represented by a line containing the input variable name(s). Blank lines are only to enhance readability. Loops indicate multiple lines of input. Conditional input is indicated by an if clause.

==NWS = 1 Wind Stress & Pressure at All Nodes and Timesteps==

===File Structure===

for k=1,[[NP]]

: [[JN]], [[WSX(k), WSY(k)]], [[PRN(k,j)]]

end k loop

===Notes===

Meteorological data is input directly to all nodes in the ADCIRC grid.

The units for pressure are meters of water.

The first set of met. data corresponds to <code>TIME=[[STATIM]]+[[DTDP]]</code>. Additional sets of met data must be provided at every time step, <code>([[WTIMINC]] = [[DTDP]])</code>.

Wind stress must be input in units of velocity squared (consistent with the units of gravity) and surface atmospheric pressure must be input in units of equivalent height of water (e.g., meters of water, feet of water that are consistent with the units of gravity). Stress in these units is obtained by dividing stress in units of force/area by the reference density of water. Pressure in these units is obtained by dividing pressure in units of force/area by the gravitational constant and the reference density of water. For example, 10^5Pa =10^5 N/m^2 =10^5 kg m/(s m)^2 divided by 9.81 m/s^2 and 10^3 kg/m^3 equals 10.2 meters of water.

==NWS = ±2 Wind Stress & Pressure at All Nodes and Specified Time Interval==

===File Structure===
for k=1, NP

: [[JN]], [[WSX(k), WSY(k)]], [[PRN(k,j)]]

end k loop

===Notes===

Meteorological data is input directly to all nodes in the ADCIRC grid.

The units for pressure are meters of H2O.

If <code>[[NWS]]=2</code>, the first set of met. data corresponds to <code>TIME=[[STATIM]]</code>. If <code>NWS=-2</code>, the first set of met data corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval and is specified in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Wind stress must be input in units of velocity squared (consistent with the units of gravity) and surface atmospheric pressure must be input in units of equivalent height of water (e.g., meters of water, feet of water that are consistent with the units of gravity).Stress in these units is obtained by dividing stress in units of force/area by the reference density of water. Pressure in these units is obtained by dividing pressure in units of force/area by the gravitational constant and the reference density of water. For example,

<code>10^5Pa =10^5 N/m^2 =10^5 kg m/(s m)^2 divided by 9.81 m/s^2 and 10^3 kg/m^3 equals 10.2 meters of water</code>

==NWS = 3 Fleet Numeric Format==

===File Structure===

[[IWTIME]]

for k = 1,[[NWLAT]]

: for j = 1,[[NWLON]]

:: [[WSPEED(k,j)]]

: end j loop

end k loop

for k = 1, NWLAT

: for j = 1, NWLON

:: [[WDIR(k,j)]]

: end j loop

end k loop

===Notes===

Meteorological data is input to a longitude, latitude grid and interpolated in space onto the ADCIRC grid.The ADCIRC grid must be in lon, lat coordinates.

The first set of met. data must be at or before the date and time listed in the Model Parameter and Periodic Boundary Condition File as the beginning time of the simulation. Additional sets of met. data must be provided every <code>WTIMINC</code>, where <code>[[WTIMINC]]</code> is the met. data time interval.Values for <code>[[NWLAT]], [[NWLON]], [[WTIMINC]]</code>, and several other parameters must be set in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Wind velocity (@ 10 m above the water surface) must be input in units of m/s (regardless of the units of gravity).

The following relations are used to compute wind stress from the input wind velocity.

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>If (DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

==NWS = ±4 PBL Hurricane Model format==

Meteorological data is input directly to a subset of nodes in the ADCIRC grid (as specified by the node number JN).The ADCIRC grid must be either in lon, lat coordinates or in meter-based Cartesian coordinates.

===File Structure===

FOR EACH WIND TIME INCREMENT

: DO UNTIL LINE = ” #”

:: [[JN]], [[WVNX(JN), WVNY(JN)]], [[PRN(k,j)]]

: END DO UNTIL

END FOR EACH

===Notes===

If <code>[[NWS]] = 4</code>, the first set of met. data corresponds to <code>TIME=[[STATIM]]</code>. If <code>[[NWS]] = -4</code>, the first set of met data corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval and is specified in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Each data line must have the format I8, 3E13.5. Data input lines are repeated for as many nodes as desired. A line containing the # symbol in column 2 indicates met data at the next time increment begins on the following
line. At each new time, any node that is not specified in the input file is assumed to have zero wind velocity and pressure = 1013.

Wind velocity (assumed to be 10m 10 minute averaged value) must be input in knots and surface atmospheric pressure must be input in hundredths of a millibar.

The following relations are used to compute wind stress from wind velocity:

<code>WIND_VEL{m/s @ 10m} = WIND_VEL{knots @ bl average}*0.5144</code> (In prior ADCIRC versions, an additional factor of 1.04 was included in the formulation to convert from 30 minute avg winds to 10 minute avg winds. This factor was removed and it is currently assumed that the input wind data uses a 10 minute averaging period. Note, this is unrelated to the value of WTIMINC).

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>if(DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

The following relationship is used in ADCIRC to convert to pressure in meters of water from pressure in hundredths of a millibar:

<code>PRESSURE{m H2O}=PRESSURE{Pa/100}*100/(GRAVITY*DENSITY H2O)</code>

==NWS = ±5 Wind Velocity & Pressure at All Nodes and Specified Time Interval==

===File Structure===

for k = 1, NP

: [[JN]], [[WVX(k), WVY(k)]], [[PRN(k,j)]]

end k loop

===Notes===

Meteorological data is input directly to all nodes in the ADCIRC grid.The ADCIRC grid must be either in lon, lat coordinates or in meter-based Cartesian coordinates.

If <code>[[NWS]]=5</code>, the first set of met. data corresponds to <code>TIME=[[STATIM]]</code>. If <code>[[NWS]]=-5</code>, the first set of met data corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval and is specified in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Wind velocity (@ 10 m above the water surface) must be input in m/s and surface atmospheric pressure must be input in meters of water.

The following relations are used to compute wind stress from wind velocity:

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>if(DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

==NWS = 6 Wind Velocity and Pressure on Rectangular Grid==

===File Structure===

for k=1, NWLAT

: for j=1, NWLON

:: [[WVXFN(k,j), WVYFN(k,j)]], [[PRN(k,j)]]

: end j loop

end k loop

===Notes===

In versions 43 and earlier the format of input was P, U, V. The input has now changed to U, V, P to be consistent with other NWS formats.

Meteorological data is input on a rectangular grid (either in Longitude, Latitude or Cartesian coordinates, consistent with the grid coordinates) and interpolated in space onto the ADCIRC grid. In setting up the meteorological grid it is assumed that y (e.g., latitude) varies from north (<code>k=1</code>) to south (<code>k=[[NWLAT]]</code>) and x (e.g., longitude) varies from west (<code>j=1</code>) to east (<code>j=[[NWLON]]</code>). The spatial extents of the meteorological grid must be consistent with the ADCIRC model domain. For example, if ADCIRC uses negative longitude values to indicate locations W of the Greenwich meridian, the meteorological file must be similarly organized. Any grid that crosses the Greenwich Meridian should be organized so that the seam occurs @ 180 deg longitude. Therefore, the meteorological and ADCIRC grids should use negative longitudes W of the Greenwich Meridian and positive longitudes to the E.

The meteorological grid MUST cover the entire ADCIRC mesh; that is, '''the ADCIRC mesh must be entirely within the meteorological grid''' or an error will result.

The first set of met. data corresponds to the beginning time of the current simulation. If the model is cold started this corresponds to <code>TIME=[[STATIM]] </code>. If the model is hot started, this corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval.Values for <code>[[NWLAT]], [[NWLON]], [[WTIMIN]]C</code>, and several other parameters must be set in the [[fort.15_file_format|fort.15 file]]. Met data is interpolated in time to the ADCIRC time step.

Wind velocity (@ 10 m above the water surface) must be input in units of m/s and surface atmospheric pressure must be input in units of Pascals = Newtons/square meter.

The following relations are used to compute wind stress from the input wind velocity.

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>If (DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

The following relationship is used in ADCIRC to convert to pressure in meters of water from pressure in Pascal:

<code>PRESSURE{m H2O}=PRESSURE{Pascal}/(GRAVITY*DENSITY H2O)</code>

==NWS = ±7 Wind Stress and Pressure on Rectangular Grid==
'''This format has not been fully implemented, though it is expected in v55.'''{{ADC version|version=?55?|relation=ge}}

===File Structure===
for k=1, NWLAT

: for j=1, NWLON

:: WVXFN(K,J),WVYFN(K,J),PRN(K,J)

: END DO

END DO

=== Notes ===

==NWS = 8 Dynamic Symmetric Holland Vortex Model==

===File Structure===
Use the [https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html ATCF Best Track/Objective Aid/Wind Radii Format].

===Notes===
Hurricane parameters are read in from the Single File Meteorological Forcing Input File. Wind velocity and atmospheric pressure are calculated at every node on the fly by ADCIRC internally using the Dynamic Holland model. The input file is fixed width (not comma separated values or csv) and is assumed to correspond to the <code>ATCF Best Track/Objective Aid/Wind Radii Format</code>. Historical tracks, real-time hindcast tracks and real-time forecast tracks may be found in this format. Selecting <code>[[NWS]] = 8</code> also requires the specification of the cold start time, storm number, and boundary layer adjustment (see <code>[[YYYY MM DD HH24 StormNumber BLAdj]]</code>). Garret’s formula is used to compute wind stress from the wind velocity.

The symmetric vortex model (<code>[[NWS]]=8</code>) in ADCIRC assumes that the longitudes in the fort.22 are west longitude, so it multiplies the longitude values by -1. It ignores the ‘E’ or ‘W’ in the longitude column of the fort.22.

The symmetric vortex model (<code>[[NWS]]=8</code>) does not use any of the isotach wind speeds or wind radii data. When reading lines labeled “BEST” from the fort.22, it obtains timing information from the year, month, day, and hour in column 3. When reading lines labeled “OFCL” from the fort.22, it uses the forecast increment (a.k.a. TAU) from column 6. The use of these two different columns by ADCIRC <code>[[NWS]]=8</code> is to maintain consistency with the official file structure for the ATCF file format.

For <code>[[NWS]]=8</code>, ADCIRC knows the current time because the user provides the year, month, day, and hour of cold start on the <code>[[WTIMINC]]</code> line in your fort.15. It also has the time that has elapsed since cold start, because that is provided in the hotstart file, if any. It then compares the current time with the date/times in the fort.22 (as described in the previous paragraph) to automatically find the right place to begin reading data from the fort.22.

So, in summary, if the whole fort.22 consists of “BEST” lines, the symmetric vortex model (<code>NWS=8</code>) only looks at column 3 for time information. And it automatically knows where to start reading cyclone data, based on the coldstart date/time the user provides in the fort.15 file.

==NWS = 9 Asymmetric Holland Vortex Model==
'''This has been deprecated and is no longer available.''' {{ADC version|version=???|relation=lt}}

==NWS = 10 National Climatic Data Center GFS==
It appears there is no fort.22 file for this format, and users should consult the [[fort.200]] page, but this hasn't been confirmed. 

Wind velocity and atmospheric pressure are read in from a sequence of National Weather Service (NWS) Aviation (AVN) model output files. Each AVN file is assumed to contain data on a Gaussian longitude, latitude grid at a single time.

===File Structure===

for k=1, [[LONB*LATB]]

: [[PG(k)]], [[UG(k)]], [[VG(k)]]

end j loop

==NWS = 11 Stripped National Weather Service (NWS) ETA 29km==
It appears there is no fort.22 file for this format, and users should consult the [[fort.200]] page, but this hasn't been confirmed. 

Wind velocity (10 m) and atmospheric pressure are read in from a sequence of stripped down National Weather Service (NWS) ETA 29km model output files.

===File Structure===

for k=1, LONB*LATB

: PG(k), UG(k), VG(k)

end j loop

==NWS = ±12 Oceanweather ASCII Format Gridded Wind and Pressure==

Oceanweather Inc (OWI) ASCII "WIN"/"PRE" format , details can be found at [[NWS12]]

==NWS = 13 Oceanweather NetCDF Format Gridded Wind and Pressure==

Oceanweather Inc (OWI) NetCDF format , details can be found at [[NWS13]] {{ADC version|version=55|relation=ge}}

==NWS = ±14 Gridded GRIB2 or NetCDF Wind and Pressure==
When using NetCDF files (fort.221.nc, fort.222.nc) as met inputs, the fort.22 is required in order to list the relevant variable names so that the internal NetCDF read routines can find the pertinent variables. In the case of GRIB2 input files (fort.221.grb2, fort.222.grb2) the fort.22 is not required because the variable names are standardized and on start-up the internal wgrb2api library prints out inventory look-up files (*.inv) that it uses to find the information contained within the *.grb2 files. {{ADC version|version=55|relation=eq}}

===File Structure===
Temporal dimension name 
Datetime variable name 
Format of the datetime time variable [special note, if first character is not a '%' then it will ignore this variable and will assume to start from the first time snap] 
Zonal (east-west) dimension name 
Longitude variable name 
Meridional (north-south) dimension name 
Latitude variable name 
Sea-level Pressure variable name [plus optional HPa units] 
Zonal 10-m Wind Velocity name 
Meridional 10-m Wind Velocity name 
Ice area-fraction name [optional, only if fort.225.nc present for ice area fraction]

===Example (WRF output)===
Time 
Times [if no datetime variable then set to dummy such as 'none'] 
%Y-%m-%d_%H:%M:%S [if no datetime variable then set to dummy such as 'none'] 
west_east 
XLONG 
south_north 
XLAT 
PSFC [optional: append HPa to PSFC (i.e., PSFCHPa) to indicate that units of pressure are in hPa/mbar, otherwise assumed to be in Pa] 
U10 
V10 
aice [optional] 

===Notes===
If the time variable is not in a datetime format (e.g., is a float in minutes since..) the datetime format can be set to a dummy name, e.g., 'minutes'. The code checks to see if the first character of the datetime format is '%'. If not the code will assume to simply begin reading from the first time snap. If the datetime variable is available the code will work out which time snap to start reading from based on the reference date, [[NCDATE]] located near or at the bottom of the [[fort.15 file]]. If pressure units are in hectopascals, add 'HPa' to the pressure variable line in the fort.22. For example, if the pressure variable is 'mslp', make it 'mslpHPa'.

==NWS = 15 H*Wind Gridded Wind and Inferred Pressure==
The goal of the implementation of the HWind capability within ADCIRC was to allow HWind files to be used as-is, without resorting to an intermediate format. As a result, the fort.22 file consists of a header line to provide some configuration parameters, and then a list of the filenames of the HWind files to be used in the ADCIRC run.

===File Structure===

comment line

[[hWindMultiplier]]

[[presssureWindRelationship]]

for i=1 to numHWindFiles

: [[hours(i)]] [[centralPressure(i)]] [[rampMult(i)]] [[filename(i)]]

end i loop

===Notes===
HWind files are data assimilated snapshots of the wind velocity fields of tropical cyclones that were produced by the NOAA Hurricane Research Division (HRD) through 2013, before becoming a private sector data product. The files have the following characteristics:

<code>the format explicitly indicates the center of the storm</code>

<code>the (u,v) data are on a regular grid</code>

<code>the regular grid is a mercator projection with origin at storm center</code>

<code>the mercator grid spacing is in meters and is uniform in x and y (dx=dy)</code>

<code>the dimensions (nx,ny) of the mercator grid are equal (nx=ny)</code>

<code>the grid dimensions change from snapshot to snapshot; for example, the first shapshot may be 161×161 while the 2nd snapshot may be 121×121 (etc)</code>

<code>sequential hwind snapshots will not be evenly spaced in time for a particular storm</code>

H*Wind data do not contain barometric pressure information. For the dvorak, knaffzehr, and specified Pc options, the barometric pressure field is computed by determining the radius to maximum winds Rmax (i.e., the distance of Vmax from the center of the storm), calculating the Holland B parameter, and then using the Holland formulation to calculate barometric pressure as a function of the distance from the center of the storm.

To illustrate the definitions and descriptions provided, a concrete example of an HWind fort.22 file is provided as follows:

<code>! first line is a comment line, max length 1024 characters</code>

<code>1.0 ! 2nd line is a velocity magnitude multiplier</code>

<code>dvorak ! 3rd line: one word for the pressure-wind relationship</code>

<code>0.0 -1 0.0 “/home/jason/hwind/al092011_0828_1330” ! time (hours), Pc (mb), ramp mult, filename</code>

<code>6.0 -1 0.5 “/home/jason/hwind/al092011_0828_1930”</code>

<code>12.0 -1 1.0 “/home/jason/hwind/al092011_0829_0130”</code>

==NWS = 16 ASCII NOAA GFDL Gridded Wind And Pressure==
The GFDL input capability uses GFDL model output files as-is; as a result, the fort.22 file consists of a list of GFDL model output files to be used in ADCIRC.

===File Structure===

comment line

[[GFDLWindMultplier]]

[[MaxExtrapolationDistance]]

for i=1 to numGFDLFiles

: [[hours(i)]] [[rampMult(i)]] [[filename(i)]]

end i loop

===Notes===

GFDL model output files are produced by the Geophysical Fluid Dynamics Laboratory at NOAA. Each ASCII GFDL model output file contains one or more nested grid dataset where the nested grids are allowed to change in time. Coarse grid data is not stored where finer nest data is given. The files are formatted as follows:

<code>Line 1: Number of grid cells (f10.4) NCELLS</code>

<code>Lines 2 through NCELLS+1: Ten columns of data formatted as 10f10.4 as follows:</code>

<code>column 1: u (m/s)</code>

<code>column 2: v (m/s)</code>

<code>column 3: Temperature (K)</code>

<code>column 4: mixing ratio(kg/kg)</code>

<code>column 5: storm accum precipitation (cm)</code>

<code>column 6: sea level pressure (hPa)</code>

<code>column 7: longitude (decimal deg)</code>

<code>column 8: latitude (decimal deg)</code>

<code>column 9: hurricane hour</code>

<code>column 10: nest number (this is not always present)</code>

To illustrate the definitions and descriptions provided, a concrete example of a GFDL fort.22 file is provided as follows:

<code>! first line is a comment line, max length 1024 characters</code>

<code>1.0 ! 2nd line is a velocity magnitude multiplier</code>

<code>100.0 ! 3rd line: maximum extrapolation distance (m)</code>

<code>0.0 -1 0.0 “/home/jason/hwind/al092011_0828_1330″ ! time (hours), Pc (mb), ramp mult, filename</code>

<code>6.0 -1 0.5 “/home/jason/hwind/al092011_0828_1930″</code>

If the ADCIRC time falls outside the interval of time covered by the GFDL model output files, ADCIRC will insert “blank snaps”, i.e., it will set the wind velocity at all mesh vertices to 0.0 m/s and the barometric pressure to a uniform background pressure of 1013mb.

==NWS = 19 Dynamic Asymmetric Holland Vortex Model==
'''Note that use of this [[Typical_ADCIRC_Parameter_Selections#Discouraged_Parameter_Selections|is discouraged]].'''

===File Structure===
The file needs to be in the [https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html ATCF Best Track/Objective Aid/Wind Radii Format].

===Notes===
User has the ability to select which isotach to use in each of the 4 quadrants. User also has ability to modify <code>RMAX</code> and <code>Holland’s B parameter</code> using the ASWIP program. The auxiliary preprocessing program ASWIP.F (located in the /wind directory and executable is created by typing, make aswip, in the work folder after adcirc executable has been generated), will generate the fort.22 input file for <code>NWS=19</code> from a <code>NWS= 9</code> formatted input file.

Hurricane parameters are read in from the Single File Meteorological Forcing Input File. It is assumed that the line in the fort.22 file with a zero as the forecast increment (i.e., column 6) corresponds to the start of the current simulation run, whether it is a hotstart or cold start. In other words, there is no option to set the NWS value negative to indicate that the file starts at the ADCIRC hotstart time. Rather, the forecast increment in hours (column 6) is used to indicate the relationship between the ADCIRC time and the data in the fort.22 file. Wind velocity and atmospheric pressure are calculated at exact finite element mesh node locations and directly coupled to ADCIRC at every time step using the asymmetric hurricane vortex formulation (Mattocks et al, 2006; Mattocks and Forbes, 2008) based on the Holland gradient wind model. The input file is assumed to correspond to the <code>ATCF Best Track/Objective Aid/Wind Radii Format</code>. Historical tracks, real-time hindcast tracks and real-time forecast tracks may be found in this format. This option uses the radii at specific wind speeds (34, 50, 64, 100 knots) reported in the four quadrants (NE, SE, SW, NW) of the storm to calculate the radius of maximum winds as a function of the azimuthal angle. Garret’s formula is used to compute wind stress from the wind velocity. The <code>NWS=19</code> option allows the user to set a value for <code>Rmax</code> and <code>Holland B Parameter</code>. Additionally the user can select the isotachs to be used for each of the 4 quadrants. The utility program aswip_1.0.3.F located in the /wind folder will generate the <code>NWS=19</code> fomatted file from a <code>NWS=9</code> formatted fort.22 input file.

In order to use the <code>NWS=19</code> option, the file needs to be in best track format. The forecast period (column #6) needs to be edited to reflect the time of the forecast/nowcast for each track location (each line) in hours from the start of the simulation (0, 6, 12, 18, etc). The original data in that column depends on what type of best track format data is being used. The original data might have 0 or other numbers in that column. See: [https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html ATCF Best Track/Objective Aid/Wind Radii Format]. It is suggested that users change the “BEST” tech type to “ASYM” in column 5 in the fort.22 file to denote that the file has been modified to accommodate the asymmetric wind formulation (the simulation time in hours in the 6th column has been added, etc.) so it will not get confused in the future with a best track file.

The <code>NWS=19</code> option requires the following variables in the fort.22 file in a best track format:

<code>Forecast time in hours (column 6); enter the time in hours in each record starting at 0</code>

<code>Latitude of the eye (column 7)</code>

<code>Longitude of the eye (column 8)</code>

<code>Maximum sustained wind speed in knots (column 9)</code>

<code>Minimum sea level pressure in MB (column 10)</code>

<code>Wind intensity in knots of the radii defined in the record (34, 50, 64 or 100 knots) (column 12)</code>

<code>Radius of specified wind intensity for quadrants 1, 2, 3, 4 in NM (columns 14, 15, 16, 17); ? 0</code>

<code>Background pressure in MB (column 18); a standard value of 1013 can be used</code>

<code>Rmax as reported in the ATCF BEST TRACK file in column 20</code>

<code>Storm Name in Column 28 ATCF file format</code>

<code>Time Record number in column 29. There can be multiple lines for a given time record depending on the number of isotachs reported in the ATCF File</code>

<code>number of isotachs reported in the ATCF file for the corresponding Time record.</code>

<code>Columns 31-34 indicate the selection of radii for that particular isotach. 0 indicates do not use this radius, and 1 indicates use this radius and corresponding wind speed.</code>

<code>Columns 35-38 are the designated Rmax values computed for each of the quadrants selected for each particular isotach.</code>

<code>Column 39 is the Holland B parameter computed using the formulas outlines in the Holland paper, and implemented using the aswip program.</code>

Available files:

* [ftp://ftp.nhc.noaa.gov/atcf/archive/ Historical storm files]

* [ftp://ftp.nhc.noaa.gov/atcf/btk/ Forecast tracks]

The format of the file is fixed and users will want to use the aswip program to be sure that the input fort.22 file is properly formatted.

<code>The command line for NWS=19 is ./aswip -n 19 -m 2 -z 1</code>

==NWS = 20 Generalized Asymmetric Holland Vortex Model (GAHM)==

===File Structure===
The file needs is similar to the NWS = 19 format with 8 additional columns of data, see notes below for more information.

===Notes===

The Generalized Asymmetric Holland Model (GAHM) provides a set of theoretical and practical improvements over previous parametric meteorological vortex models in ADCIRC.

<code>Forecast time in hours (column 6); enter the time in hours in each record starting at 0</code>

<code>Latitude of the eye (column 7)</code>

<code>Longitude of the eye (column 8)</code>

<code>Maximum sustained wind speed in knots (column 9)</code>

<code>Minimum sea level pressure in MB (column 10)</code>

<code>Wind intensity in knots of the radii defined in the record (34, 50, 64 or 100 knots) (column 12)</code>

<code>Radius of specified wind intensity for quadrants 1, 2, 3, 4 in NM (columns 14, 15, 16, 17); ? 0</code>

<code>Background pressure in MB (column 18); a standard value of 1013 can be used</code>

<code>Rmax as reported in the ATCF BEST TRACK file in column 20</code>

<code>Storm Name in Column 28 ATCF file format</code>

<code>Time Record number in column 29. There can be multiple lines for a given time record depending on the number of isotachs reported in the ATCF File</code>

<code>number of isotachs reported in the ATCF file for the corresponding Time record.</code>

<code>Columns 31-34 indicate the selection of radii for that particular isotach. 0 indicates do not use this radius, and 1 indicates use this radius and corresponding wind speed.</code>

<code>Columns 35-38 are the designated Rmax values computed for each of the quadrants selected for each particular isotach.</code>

<code>Column 39 is the Holland B parameter computed using the formulas outlines in the Holland paper, and implemented using the aswip program.</code>

<code>Column 40-43 is the quadrant-varying Holland B parameter</code>

<code>Column 44-47 are the quadrant-varying Vmax calculated at the top of the planetary boundary (a wind reduction factor is applied to reduce the wind speed at the boundary to the 10-m surface)</code>

Historical storm files can be found archived here.

Forecast tracks can be found here.

The format of the file is fixed and users will want to use the aswip program to be sure that the input fort.22 file is properly formatted.

Options for the aswip program using NWS = 20 are the following:

<code>./aswip -n # -m # -z #</code>

;-n = nws option

;-m = methods of selecting isotachs for use in computation of radius/radii to maximum winds

:1: always use the 34kt isotach</code>

:2: use the highest available isotach in any quadrant each time

:3: use the 50kt isotach if it is available; otherwise use the 34kt isotach

:4: use all available isotachs (must choose this for GAHM/NWS=20)

;-z = approaches solving for Rmax

:1 = only rotate wind vectors afterward

:2 = rotate wind vectors before and afterwards (use this for NWS=20)

So the command line for <code>NWS=20</code> is: <code>./aswip -n 20 -m 4 -z 2</code>

==NWS = 30 Blended GAHM & Background Gridded Wind and Pressure==
This format is a combination of GAHM (<code>NWS=20</code>) and a gridded background meteorological field (<code>NWS=12</code>). The core of a tropical cyclone is represented using the GAHM model and read in from a file named NWS_20_fort.22, which should be created following the procedure presented in the [[#NWS = 20 Generalized Asymmetric Holland Vortex Model (GAHM)|section on <code>NWS=20</code>]]. The user must also supply gridded wind and pressure files in the form of an OWI-style fort.22 file, a fort.221 file, and a fort.222 file, details on these are in the [[#NWS = ±12 Oceanweather ASCII Format Gridded Wind and Pressure|section on <code>NWS=12</code>]]. ADCIRC internally blends the wind and pressure fields from these two sets of inputs over a user-controlled distance. Specifically, the <code>[[pureVortex]]</code> and <code>[[pureBackground]]</code> inputs in the [[fort.15 file]] (for formatting, see info on the [[Supplemental meteorological/wave/ice parameters|meteorological parameter line]]) are coefficients used to define where transitions between the vortex and background meteorology occur. At or within the distance <code>pureVortex*vortexRMW</code> of the storm's center, the GAHM meteorology is used. At or beyond the distance <code>pureBackground*vortexRMW</code> of the storm's center, the background meteorology is used. In between these, a linear distance-weighted average of the two sets of meteorology is used to define the forcing.

[[Category:input files]]
[[Category:meteorology]]
[[Category:unverified behavior]]

Fort.22 file

2024-10-02T19:29:40Z

Jddratli: /* Notes */

A single meteorological input file (wind velocity and atmospheric pressure) is read when meteorological forcing has been indicated by the <code>[[NWS]]</code> parameter in the [[fort.15 file]]. More precisely, the format of and need for the fort.22 file depend on the ones and tens (i.e. the last 2) digits and the sign (positive/negative) of <code>NWS</code> (see [[NWS#Value_Seen_in_fort.15_File|here]]). See also the [[supplemental meteorological/wave/ice parameters]] and [[wind stress]] pages.

== General Notes ==
Unless otherwise specified for a given format, ADCIRC expects wind data to represent [[Wind_Stress#Definition_of_Winds|specific conditions]] and pressure data to be sea level pressure. Where necessary, ADCIRC assumes a "background" atmospheric pressure of 1013 millibars.

Meteorological data in most formats must be provided for the entire model run, otherwise the run will crash. Exceptions include OWI (<code>NWS=12</code>) and GFDL (<code>NWS=16</code>).

For most formats, latitude and longitude coordinates describing the spatial extents of the meteorological data must follow the convention of the ADCIRC model domain. For example, if the [[fort.14 file|mesh]] uses negative longitude values to indicate locations West of the Greenwich meridian, the meteorological file must be similarly organized. Any grid that crosses the Greenwich Meridian should be organized so that the seam occurs at 180 deg longitude. Therefore, the meteorological and ADCIRC grids should use negative longitudes West of the Greenwich Meridian and positive longitudes to the East.

== File Format ==
The remainder of this page is devoted to the formats of the fort.22 file for the different values of <code>NWS</code>. Each line of input data is represented by a line containing the input variable name(s). Blank lines are only to enhance readability. Loops indicate multiple lines of input. Conditional input is indicated by an if clause.

==NWS = 1 Wind Stress & Pressure at All Nodes and Timesteps==

===File Structure===

for k=1,[[NP]]

: [[JN]], [[WSX(k), WSY(k)]], [[PRN(k,j)]]

end k loop

===Notes===

Meteorological data is input directly to all nodes in the ADCIRC grid.

The units for pressure are meters of water.

The first set of met. data corresponds to <code>TIME=[[STATIM]]+[[DTDP]]</code>. Additional sets of met data must be provided at every time step, <code>([[WTIMINC]] = [[DTDP]])</code>.

Wind stress must be input in units of velocity squared (consistent with the units of gravity) and surface atmospheric pressure must be input in units of equivalent height of water (e.g., meters of water, feet of water that are consistent with the units of gravity). Stress in these units is obtained by dividing stress in units of force/area by the reference density of water. Pressure in these units is obtained by dividing pressure in units of force/area by the gravitational constant and the reference density of water. For example, 10^5Pa =10^5 N/m^2 =10^5 kg m/(s m)^2 divided by 9.81 m/s^2 and 10^3 kg/m^3 equals 10.2 meters of water.

==NWS = ±2 Wind Stress & Pressure at All Nodes and Specified Time Interval==

===File Structure===
for k=1, NP

: [[JN]], [[WSX(k), WSY(k)]], [[PRN(k,j)]]

end k loop

===Notes===

Meteorological data is input directly to all nodes in the ADCIRC grid.

The units for pressure are meters of H2O.

If <code>[[NWS]]=2</code>, the first set of met. data corresponds to <code>TIME=[[STATIM]]</code>. If <code>NWS=-2</code>, the first set of met data corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval and is specified in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Wind stress must be input in units of velocity squared (consistent with the units of gravity) and surface atmospheric pressure must be input in units of equivalent height of water (e.g., meters of water, feet of water that are consistent with the units of gravity).Stress in these units is obtained by dividing stress in units of force/area by the reference density of water. Pressure in these units is obtained by dividing pressure in units of force/area by the gravitational constant and the reference density of water. For example,

<code>10^5Pa =10^5 N/m^2 =10^5 kg m/(s m)^2 divided by 9.81 m/s^2 and 10^3 kg/m^3 equals 10.2 meters of water</code>

==NWS = 3 Fleet Numeric Format==

===File Structure===

[[IWTIME]]

for k = 1,[[NWLAT]]

: for j = 1,[[NWLON]]

:: [[WSPEED(k,j)]]

: end j loop

end k loop

for k = 1, NWLAT

: for j = 1, NWLON

:: [[WDIR(k,j)]]

: end j loop

end k loop

===Notes===

Meteorological data is input to a longitude, latitude grid and interpolated in space onto the ADCIRC grid.The ADCIRC grid must be in lon, lat coordinates.

The first set of met. data must be at or before the date and time listed in the Model Parameter and Periodic Boundary Condition File as the beginning time of the simulation. Additional sets of met. data must be provided every <code>WTIMINC</code>, where <code>[[WTIMINC]]</code> is the met. data time interval.Values for <code>[[NWLAT]], [[NWLON]], [[WTIMINC]]</code>, and several other parameters must be set in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Wind velocity (@ 10 m above the water surface) must be input in units of m/s (regardless of the units of gravity).

The following relations are used to compute wind stress from the input wind velocity.

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>If (DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

==NWS = ±4 PBL Hurricane Model format==

Meteorological data is input directly to a subset of nodes in the ADCIRC grid (as specified by the node number JN).The ADCIRC grid must be either in lon, lat coordinates or in meter-based Cartesian coordinates.

===File Structure===

FOR EACH WIND TIME INCREMENT

: DO UNTIL LINE = ” #”

:: [[JN]], [[WVNX(JN), WVNY(JN)]], [[PRN(k,j)]]

: END DO UNTIL

END FOR EACH

===Notes===

If <code>[[NWS]] = 4</code>, the first set of met. data corresponds to <code>TIME=[[STATIM]]</code>. If <code>[[NWS]] = -4</code>, the first set of met data corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval and is specified in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Each data line must have the format I8, 3E13.5. Data input lines are repeated for as many nodes as desired. A line containing the # symbol in column 2 indicates met data at the next time increment begins on the following
line. At each new time, any node that is not specified in the input file is assumed to have zero wind velocity and pressure = 1013.

Wind velocity (assumed to be 10m 10 minute averaged value) must be input in knots and surface atmospheric pressure must be input in hundredths of a millibar.

The following relations are used to compute wind stress from wind velocity:

<code>WIND_VEL{m/s @ 10m} = WIND_VEL{knots @ bl average}*0.5144</code> (In prior ADCIRC versions, an additional factor of 1.04 was included in the formulation to convert from 30 minute avg winds to 10 minute avg winds. This factor was removed and it is currently assumed that the input wind data uses a 10 minute averaging period. Note, this is unrelated to the value of WTIMINC).

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>if(DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

The following relationship is used in ADCIRC to convert to pressure in meters of water from pressure in hundredths of a millibar:

<code>PRESSURE{m H2O}=PRESSURE{Pa/100}*100/(GRAVITY*DENSITY H2O)</code>

==NWS = ±5 Wind Velocity & Pressure at All Nodes and Specified Time Interval==

===File Structure===

for k = 1, NP

: [[JN]], [[WVX(k), WVY(k)]], [[PRN(k,j)]]

end k loop

===Notes===

Meteorological data is input directly to all nodes in the ADCIRC grid.The ADCIRC grid must be either in lon, lat coordinates or in meter-based Cartesian coordinates.

If <code>[[NWS]]=5</code>, the first set of met. data corresponds to <code>TIME=[[STATIM]]</code>. If <code>[[NWS]]=-5</code>, the first set of met data corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval and is specified in the Model Parameter and Periodic Boundary Condition File. Met data is interpolated in time to the ADCIRC time step.

Wind velocity (@ 10 m above the water surface) must be input in m/s and surface atmospheric pressure must be input in meters of water.

The following relations are used to compute wind stress from wind velocity:

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>if(DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

==NWS = 6 Wind Velocity and Pressure on Rectangular Grid==

===File Structure===

for k=1, NWLAT

: for j=1, NWLON

:: [[WVXFN(k,j), WVYFN(k,j)]], [[PRN(k,j)]]

: end j loop

end k loop

===Notes===

In versions 43 and earlier the format of input was P, U, V. The input has now changed to U, V, P to be consistent with other NWS formats.

Meteorological data is input on a rectangular grid (either in Longitude, Latitude or Cartesian coordinates, consistent with the grid coordinates) and interpolated in space onto the ADCIRC grid. In setting up the meteorological grid it is assumed that y (e.g., latitude) varies from north (<code>k=1</code>) to south (<code>k=[[NWLAT]]</code>) and x (e.g., longitude) varies from west (<code>j=1</code>) to east (<code>j=[[NWLON]]</code>). The spatial extents of the meteorological grid must be consistent with the ADCIRC model domain. For example, if ADCIRC uses negative longitude values to indicate locations W of the Greenwich meridian, the meteorological file must be similarly organized. Any grid that crosses the Greenwich Meridian should be organized so that the seam occurs @ 180 deg longitude. Therefore, the meteorological and ADCIRC grids should use negative longitudes W of the Greenwich Meridian and positive longitudes to the E.

The meteorological grid MUST cover the entire ADCIRC mesh; that is, '''the ADCIRC mesh must be entirely within the meteorological grid''' or an error will result.

The first set of met. data corresponds to the beginning time of the current simulation. If the model is cold started this corresponds to <code>TIME=[[STATIM]] </code>. If the model is hot started, this corresponds to <code>TIME=HOT START TIME</code>. Additional sets of met. data must be provided every <code>[[WTIMINC]]</code>, where <code>[[WTIMINC]]</code> is the met. data time interval.Values for <code>[[NWLAT]], [[NWLON]], [[WTIMIN]]C</code>, and several other parameters must be set in the [[fort.15_file_format|fort.15 file]]. Met data is interpolated in time to the ADCIRC time step.

Wind velocity (@ 10 m above the water surface) must be input in units of m/s and surface atmospheric pressure must be input in units of Pascals = Newtons/square meter.

The following relations are used to compute wind stress from the input wind velocity.

<code>WIND_SPEED = magnitude of WIND_VEL</code>

<code>DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)</code>

<code>If (DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003</code>

<code>WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED</code>

The following relationship is used in ADCIRC to convert to pressure in meters of water from pressure in Pascal:

<code>PRESSURE{m H2O}=PRESSURE{Pascal}/(GRAVITY*DENSITY H2O)</code>

==NWS = ±7 Wind Stress and Pressure on Rectangular Grid==
'''This format has not been fully implemented, though it is expected in v55.'''{{ADC version|version=?55?|relation=ge}}

===File Structure===
for k=1, NWLAT

: for j=1, NWLON

:: WVXFN(K,J),WVYFN(K,J),PRN(K,J)

: END DO

END DO

=== Notes ===

==NWS = 8 Dynamic Symmetric Holland Vortex Model==

===File Structure===
Use the [https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html ATCF Best Track/Objective Aid/Wind Radii Format].

===Notes===
Hurricane parameters are read in from the Single File Meteorological Forcing Input File. Wind velocity and atmospheric pressure are calculated at every node on the fly by ADCIRC internally using the Dynamic Holland model. The input file is fixed width (not comma separated values or csv) and is assumed to correspond to the <code>ATCF Best Track/Objective Aid/Wind Radii Format</code>. Historical tracks, real-time hindcast tracks and real-time forecast tracks may be found in this format. Selecting <code>[[NWS]] = 8</code> also requires the specification of the cold start time, storm number, and boundary layer adjustment (see <code>[[YYYY MM DD HH24 StormNumber BLAdj]]</code>). Garret’s formula is used to compute wind stress from the wind velocity.

The symmetric vortex model (<code>[[NWS]]=8</code>) in ADCIRC assumes that the longitudes in the fort.22 are west longitude, so it multiplies the longitude values by -1. It ignores the ‘E’ or ‘W’ in the longitude column of the fort.22.

The symmetric vortex model (<code>[[NWS]]=8</code>) does not use any of the isotach wind speeds or wind radii data. When reading lines labeled “BEST” from the fort.22, it obtains timing information from the year, month, day, and hour in column 3. When reading lines labeled “OFCL” from the fort.22, it uses the forecast increment (a.k.a. TAU) from column 6. The use of these two different columns by ADCIRC <code>[[NWS]]=8</code> is to maintain consistency with the official file structure for the ATCF file format.

For <code>[[NWS]]=8</code>, ADCIRC knows the current time because the user provides the year, month, day, and hour of cold start on the <code>[[WTIMINC]]</code> line in your fort.15. It also has the time that has elapsed since cold start, because that is provided in the hotstart file, if any. It then compares the current time with the date/times in the fort.22 (as described in the previous paragraph) to automatically find the right place to begin reading data from the fort.22.

So, in summary, if the whole fort.22 consists of “BEST” lines, the symmetric vortex model (<code>NWS=8</code>) only looks at column 3 for time information. And it automatically knows where to start reading cyclone data, based on the coldstart date/time the user provides in the fort.15 file.

==NWS = 9 Asymmetric Holland Vortex Model==
'''This has been deprecated and is no longer available.''' {{ADC version|version=???|relation=lt}}

==NWS = 10 National Climatic Data Center GFS==
It appears there is no fort.22 file for this format, and users should consult the [[fort.200]] page, but this hasn't been confirmed. 

Wind velocity and atmospheric pressure are read in from a sequence of National Weather Service (NWS) Aviation (AVN) model output files. Each AVN file is assumed to contain data on a Gaussian longitude, latitude grid at a single time.

===File Structure===

for k=1, [[LONB*LATB]]

: [[PG(k)]], [[UG(k)]], [[VG(k)]]

end j loop

==NWS = 11 Stripped National Weather Service (NWS) ETA 29km==
It appears there is no fort.22 file for this format, and users should consult the [[fort.200]] page, but this hasn't been confirmed. 

Wind velocity (10 m) and atmospheric pressure are read in from a sequence of stripped down National Weather Service (NWS) ETA 29km model output files.

===File Structure===

for k=1, LONB*LATB

: PG(k), UG(k), VG(k)

end j loop

==NWS = ±12 Oceanweather ASCII Format Gridded Wind and Pressure==

Oceanweather Inc (OWI) ASCII "WIN"/"PRE" format , details can be found at [[NWS12]]

==NWS = 13 Oceanweather NetCDF Format Gridded Wind and Pressure==

Oceanweather Inc (OWI) NetCDF format , details can be found at [[NWS13]] {{ADC version|version=55|relation=ge}}

==NWS = ±14 Gridded GRIB2 or NetCDF Wind and Pressure==
When using NetCDF files (fort.221.nc, fort.222.nc) as met inputs, the fort.22 is required in order to list the relevant variable names so that the internal NetCDF read routines can find the pertinent variables. In the case of GRIB2 input files (fort.221.grb2, fort.222.grb2) the fort.22 is not required because the variable names are standardized and on start-up the internal wgrb2api library prints out inventory look-up files (*.inv) that it uses to find the information contained within the *.grb2 files. {{ADC version|version=55|relation=eq}}

===File Structure===
Temporal dimension name 
Datetime variable name 
Format of the datetime time variable [special note, if first character is not a '%' then it will ignore this variable and will assume to start from the first time snap] 
Zonal (east-west) dimension name 
Longitude variable name 
Meridional (north-south) dimension name 
Latitude variable name 
Sea-level Pressure variable name 
Zonal 10-m Wind Velocity name 
Meridional 10-m Wind Velocity name 
Ice area-fraction name [optional, only if fort.225.nc present for ice area fraction]

===Example (WRF output)===
Time 
Times [if no datetime variable then set to dummy such as 'none'] 
%Y-%m-%d_%H:%M:%S [if no datetime variable then set to dummy such as 'none'] 
west_east 
XLONG 
south_north 
XLAT 
PSFC 
U10 
V10 
aice [optional] 

===Notes===
If the time variable is not in a datetime format (e.g., is a float in minutes since..) the datetime format can be set to a dummy name, e.g., 'minutes'. The code checks to see if the first character of the datetime format is '%'. If not the code will assume to simply begin reading from the first time snap. If the datetime variable is available the code will work out which time snap to start reading from based on the reference date, [[NCDATE]] located near or at the bottom of the [[fort.15 file]]. If pressure units are in hectopascals, add 'HPa' to the pressure variable line in the fort.22. For example, if the pressure variable is 'mslp', make it 'mslpHPa'.

==NWS = 15 H*Wind Gridded Wind and Inferred Pressure==
The goal of the implementation of the HWind capability within ADCIRC was to allow HWind files to be used as-is, without resorting to an intermediate format. As a result, the fort.22 file consists of a header line to provide some configuration parameters, and then a list of the filenames of the HWind files to be used in the ADCIRC run.

===File Structure===

comment line

[[hWindMultiplier]]

[[presssureWindRelationship]]

for i=1 to numHWindFiles

: [[hours(i)]] [[centralPressure(i)]] [[rampMult(i)]] [[filename(i)]]

end i loop

===Notes===
HWind files are data assimilated snapshots of the wind velocity fields of tropical cyclones that were produced by the NOAA Hurricane Research Division (HRD) through 2013, before becoming a private sector data product. The files have the following characteristics:

<code>the format explicitly indicates the center of the storm</code>

<code>the (u,v) data are on a regular grid</code>

<code>the regular grid is a mercator projection with origin at storm center</code>

<code>the mercator grid spacing is in meters and is uniform in x and y (dx=dy)</code>

<code>the dimensions (nx,ny) of the mercator grid are equal (nx=ny)</code>

<code>the grid dimensions change from snapshot to snapshot; for example, the first shapshot may be 161×161 while the 2nd snapshot may be 121×121 (etc)</code>

<code>sequential hwind snapshots will not be evenly spaced in time for a particular storm</code>

H*Wind data do not contain barometric pressure information. For the dvorak, knaffzehr, and specified Pc options, the barometric pressure field is computed by determining the radius to maximum winds Rmax (i.e., the distance of Vmax from the center of the storm), calculating the Holland B parameter, and then using the Holland formulation to calculate barometric pressure as a function of the distance from the center of the storm.

To illustrate the definitions and descriptions provided, a concrete example of an HWind fort.22 file is provided as follows:

<code>! first line is a comment line, max length 1024 characters</code>

<code>1.0 ! 2nd line is a velocity magnitude multiplier</code>

<code>dvorak ! 3rd line: one word for the pressure-wind relationship</code>

<code>0.0 -1 0.0 “/home/jason/hwind/al092011_0828_1330” ! time (hours), Pc (mb), ramp mult, filename</code>

<code>6.0 -1 0.5 “/home/jason/hwind/al092011_0828_1930”</code>

<code>12.0 -1 1.0 “/home/jason/hwind/al092011_0829_0130”</code>

==NWS = 16 ASCII NOAA GFDL Gridded Wind And Pressure==
The GFDL input capability uses GFDL model output files as-is; as a result, the fort.22 file consists of a list of GFDL model output files to be used in ADCIRC.

===File Structure===

comment line

[[GFDLWindMultplier]]

[[MaxExtrapolationDistance]]

for i=1 to numGFDLFiles

: [[hours(i)]] [[rampMult(i)]] [[filename(i)]]

end i loop

===Notes===

GFDL model output files are produced by the Geophysical Fluid Dynamics Laboratory at NOAA. Each ASCII GFDL model output file contains one or more nested grid dataset where the nested grids are allowed to change in time. Coarse grid data is not stored where finer nest data is given. The files are formatted as follows:

<code>Line 1: Number of grid cells (f10.4) NCELLS</code>

<code>Lines 2 through NCELLS+1: Ten columns of data formatted as 10f10.4 as follows:</code>

<code>column 1: u (m/s)</code>

<code>column 2: v (m/s)</code>

<code>column 3: Temperature (K)</code>

<code>column 4: mixing ratio(kg/kg)</code>

<code>column 5: storm accum precipitation (cm)</code>

<code>column 6: sea level pressure (hPa)</code>

<code>column 7: longitude (decimal deg)</code>

<code>column 8: latitude (decimal deg)</code>

<code>column 9: hurricane hour</code>

<code>column 10: nest number (this is not always present)</code>

To illustrate the definitions and descriptions provided, a concrete example of a GFDL fort.22 file is provided as follows:

<code>! first line is a comment line, max length 1024 characters</code>

<code>1.0 ! 2nd line is a velocity magnitude multiplier</code>

<code>100.0 ! 3rd line: maximum extrapolation distance (m)</code>

<code>0.0 -1 0.0 “/home/jason/hwind/al092011_0828_1330″ ! time (hours), Pc (mb), ramp mult, filename</code>

<code>6.0 -1 0.5 “/home/jason/hwind/al092011_0828_1930″</code>

If the ADCIRC time falls outside the interval of time covered by the GFDL model output files, ADCIRC will insert “blank snaps”, i.e., it will set the wind velocity at all mesh vertices to 0.0 m/s and the barometric pressure to a uniform background pressure of 1013mb.

==NWS = 19 Dynamic Asymmetric Holland Vortex Model==
'''Note that use of this [[Typical_ADCIRC_Parameter_Selections#Discouraged_Parameter_Selections|is discouraged]].'''

===File Structure===
The file needs to be in the [https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html ATCF Best Track/Objective Aid/Wind Radii Format].

===Notes===
User has the ability to select which isotach to use in each of the 4 quadrants. User also has ability to modify <code>RMAX</code> and <code>Holland’s B parameter</code> using the ASWIP program. The auxiliary preprocessing program ASWIP.F (located in the /wind directory and executable is created by typing, make aswip, in the work folder after adcirc executable has been generated), will generate the fort.22 input file for <code>NWS=19</code> from a <code>NWS= 9</code> formatted input file.

Hurricane parameters are read in from the Single File Meteorological Forcing Input File. It is assumed that the line in the fort.22 file with a zero as the forecast increment (i.e., column 6) corresponds to the start of the current simulation run, whether it is a hotstart or cold start. In other words, there is no option to set the NWS value negative to indicate that the file starts at the ADCIRC hotstart time. Rather, the forecast increment in hours (column 6) is used to indicate the relationship between the ADCIRC time and the data in the fort.22 file. Wind velocity and atmospheric pressure are calculated at exact finite element mesh node locations and directly coupled to ADCIRC at every time step using the asymmetric hurricane vortex formulation (Mattocks et al, 2006; Mattocks and Forbes, 2008) based on the Holland gradient wind model. The input file is assumed to correspond to the <code>ATCF Best Track/Objective Aid/Wind Radii Format</code>. Historical tracks, real-time hindcast tracks and real-time forecast tracks may be found in this format. This option uses the radii at specific wind speeds (34, 50, 64, 100 knots) reported in the four quadrants (NE, SE, SW, NW) of the storm to calculate the radius of maximum winds as a function of the azimuthal angle. Garret’s formula is used to compute wind stress from the wind velocity. The <code>NWS=19</code> option allows the user to set a value for <code>Rmax</code> and <code>Holland B Parameter</code>. Additionally the user can select the isotachs to be used for each of the 4 quadrants. The utility program aswip_1.0.3.F located in the /wind folder will generate the <code>NWS=19</code> fomatted file from a <code>NWS=9</code> formatted fort.22 input file.

In order to use the <code>NWS=19</code> option, the file needs to be in best track format. The forecast period (column #6) needs to be edited to reflect the time of the forecast/nowcast for each track location (each line) in hours from the start of the simulation (0, 6, 12, 18, etc). The original data in that column depends on what type of best track format data is being used. The original data might have 0 or other numbers in that column. See: [https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html ATCF Best Track/Objective Aid/Wind Radii Format]. It is suggested that users change the “BEST” tech type to “ASYM” in column 5 in the fort.22 file to denote that the file has been modified to accommodate the asymmetric wind formulation (the simulation time in hours in the 6th column has been added, etc.) so it will not get confused in the future with a best track file.

The <code>NWS=19</code> option requires the following variables in the fort.22 file in a best track format:

<code>Forecast time in hours (column 6); enter the time in hours in each record starting at 0</code>

<code>Latitude of the eye (column 7)</code>

<code>Longitude of the eye (column 8)</code>

<code>Maximum sustained wind speed in knots (column 9)</code>

<code>Minimum sea level pressure in MB (column 10)</code>

<code>Wind intensity in knots of the radii defined in the record (34, 50, 64 or 100 knots) (column 12)</code>

<code>Radius of specified wind intensity for quadrants 1, 2, 3, 4 in NM (columns 14, 15, 16, 17); ? 0</code>

<code>Background pressure in MB (column 18); a standard value of 1013 can be used</code>

<code>Rmax as reported in the ATCF BEST TRACK file in column 20</code>

<code>Storm Name in Column 28 ATCF file format</code>

<code>Time Record number in column 29. There can be multiple lines for a given time record depending on the number of isotachs reported in the ATCF File</code>

<code>number of isotachs reported in the ATCF file for the corresponding Time record.</code>

<code>Columns 31-34 indicate the selection of radii for that particular isotach. 0 indicates do not use this radius, and 1 indicates use this radius and corresponding wind speed.</code>

<code>Columns 35-38 are the designated Rmax values computed for each of the quadrants selected for each particular isotach.</code>

<code>Column 39 is the Holland B parameter computed using the formulas outlines in the Holland paper, and implemented using the aswip program.</code>

Available files:

* [ftp://ftp.nhc.noaa.gov/atcf/archive/ Historical storm files]

* [ftp://ftp.nhc.noaa.gov/atcf/btk/ Forecast tracks]

The format of the file is fixed and users will want to use the aswip program to be sure that the input fort.22 file is properly formatted.

<code>The command line for NWS=19 is ./aswip -n 19 -m 2 -z 1</code>

==NWS = 20 Generalized Asymmetric Holland Vortex Model (GAHM)==

===File Structure===
The file needs is similar to the NWS = 19 format with 8 additional columns of data, see notes below for more information.

===Notes===

The Generalized Asymmetric Holland Model (GAHM) provides a set of theoretical and practical improvements over previous parametric meteorological vortex models in ADCIRC.

<code>Forecast time in hours (column 6); enter the time in hours in each record starting at 0</code>

<code>Latitude of the eye (column 7)</code>

<code>Longitude of the eye (column 8)</code>

<code>Maximum sustained wind speed in knots (column 9)</code>

<code>Minimum sea level pressure in MB (column 10)</code>

<code>Wind intensity in knots of the radii defined in the record (34, 50, 64 or 100 knots) (column 12)</code>

<code>Radius of specified wind intensity for quadrants 1, 2, 3, 4 in NM (columns 14, 15, 16, 17); ? 0</code>

<code>Background pressure in MB (column 18); a standard value of 1013 can be used</code>

<code>Rmax as reported in the ATCF BEST TRACK file in column 20</code>

<code>Storm Name in Column 28 ATCF file format</code>

<code>Time Record number in column 29. There can be multiple lines for a given time record depending on the number of isotachs reported in the ATCF File</code>

<code>number of isotachs reported in the ATCF file for the corresponding Time record.</code>

<code>Columns 31-34 indicate the selection of radii for that particular isotach. 0 indicates do not use this radius, and 1 indicates use this radius and corresponding wind speed.</code>

<code>Columns 35-38 are the designated Rmax values computed for each of the quadrants selected for each particular isotach.</code>

<code>Column 39 is the Holland B parameter computed using the formulas outlines in the Holland paper, and implemented using the aswip program.</code>

<code>Column 40-43 is the quadrant-varying Holland B parameter</code>

<code>Column 44-47 are the quadrant-varying Vmax calculated at the top of the planetary boundary (a wind reduction factor is applied to reduce the wind speed at the boundary to the 10-m surface)</code>

Historical storm files can be found archived here.

Forecast tracks can be found here.

The format of the file is fixed and users will want to use the aswip program to be sure that the input fort.22 file is properly formatted.

Options for the aswip program using NWS = 20 are the following:

<code>./aswip -n # -m # -z #</code>

;-n = nws option

;-m = methods of selecting isotachs for use in computation of radius/radii to maximum winds

:1: always use the 34kt isotach</code>

:2: use the highest available isotach in any quadrant each time

:3: use the 50kt isotach if it is available; otherwise use the 34kt isotach

:4: use all available isotachs (must choose this for GAHM/NWS=20)

;-z = approaches solving for Rmax

:1 = only rotate wind vectors afterward

:2 = rotate wind vectors before and afterwards (use this for NWS=20)

So the command line for <code>NWS=20</code> is: <code>./aswip -n 20 -m 4 -z 2</code>

==NWS = 30 Blended GAHM & Background Gridded Wind and Pressure==
This format is a combination of GAHM (<code>NWS=12</code>) and a gridded background meteorological field (<code>NWS=20</code>). The core of a tropical cyclone is represented using the GAHM model and read in from a file named NWS_20_fort.22, which should be created following the procedure presented in the [[#NWS = 20 Generalized Asymmetric Holland Vortex Model (GAHM)|section on <code>NWS=20</code>]]. The user must also supply gridded wind and pressure files in the form of an OWI-style fort.22 file, a fort.221 file, and a fort.222 file, details on these are in the [[#NWS = ±12 Oceanweather ASCII Format Gridded Wind and Pressure|section on <code>NWS=12</code>]]. ADCIRC internally blends the wind and pressure fields from these two sets of inputs over a user-controlled distance. Specifically, the <code>[[pureVortex]]</code> and <code>[[pureBackground]]</code> inputs in the [[fort.15 file]] (for formatting, see info on the [[Supplemental meteorological/wave/ice parameters|meteorological parameter line]]) are coefficients used to define where transitions between the vortex and background meteorology occur. At or within the distance <code>pureVortex*vortexRMW</code> of the storm's center, the GAHM meteorology is used. At or beyond the distance <code>pureBackground*vortexRMW</code> of the storm's center, the background meteorology is used. In between these, a linear distance-weighted average of the two sets of meteorology is used to define the forcing.

[[Category:input files]]
[[Category:meteorology]]
[[Category:unverified behavior]]

Fort.13 file

2020-06-10T16:26:25Z

Jddratli: /* Wave Refraction in SWAN */

The fort.13 file contains nodal attributes, which can vary spatially. For each attribute, one or more values are specified at each node. The number of values and their meaning(s) varies by attribute.

== File Format ==
See [[fort.13 file format]] for details. This file is only read when [[NWP]] > 0 in the Model Parameter and Periodic Boundary Condition File ([[fort.15 file]]).

== Nodal Attributes ==
Note that units for nodal attributes are specified by the user in the fort.13 file, though ADCIRC may require that attributes be supplied in certain units.

===Advection State===
'''Nodal attribute name:''' advection_state 
'''Description:''' The advection_state nodal attribute is used to provide fine grained control over the NOLICA and NOLICAT parameters, so that they can be set on an element-by-element basis. The bathymetric depth at the three nodes of an element are compared to the corresponding nodal attribute values, and if the bathymetric depth at all three nodes is greater than or equal to the corresponding nodal attribute value, the values of NOLICA and NOLICAT will be set to the value indicated in the Model Parameter and Periodic Boundary Condition (fort.15) file. If the bathymetric depth at any of the three nodes of a particular element is less than the corresponding nodal attribute value, the values of NOLICA and NOLICAT will be set to zero on that element. 
'''Requirement:''' Optional. 
'''Units:''' Length. 
'''Values:''' Any. 
'''ADCIRC Variable:''' AdvectionState 

===Bottom Roughness===
'''Nodal attribute name:''' bottom_roughness_length 
'''Description:''' Roughness length for 3D bottom friction calculations. Has no effect on a 2DDI ADCIRC run. 
'''Requirement:''' Optional. 
'''Units:''' Length (m) 
'''Values:''' Greater than zero. A reasonable range for the bottom_roughness_length would be 0.001m -0.2m , (densely vegetated overland values would have an upper limit of about 0.2-0.5m and smooth muddy bottoms could have values as low as 0.0001 m). 
'''ADCIRC Variable:''' Z0b_var 

=== Bridge Pilings Friction Parameters ===
'''Nodal attribute name:''' bridge_pilings_friction_parameters 
'''Description:''' Extra friction from bridge pilings. See Note below. 
'''Requirement:''' Very optional. 
'''Units:''' Vary, see note below and BK, BALPHA, BDELX and POAN. 
'''Values:''' Vary, see note below and BK, BALPHA, BDELX and POAN. 
'''ADCIRC Variable:''' BK, BAlpha, BDelX, POAN 
'''Note:''' Special considerations must be used when designing a grid for an ADCIRC application that includes the effects of bridge pilings. Specifically, it is necessary to build the grid to provide at least three rows of nodes that parallel the bridge span. One row of nodes (centerline nodes) should lie along the approximate centerline of the bridge while the second and third rows of nodes (adjacent nodes) should lie on either side of the centerline nodes in the along steam direction. An initial implementation of obstruction drag in ADCIRC placed this drag entirely at the row of centerline nodes. However, tests showed that this arrangement led to significant oscillations in the numerical solution. The oscillations abated when the obstruction drag was distributed in the along stream direction so that 25 percent was located at each row of adjacent nodes and 50 percent was located at the row of centerline nodes. Node numbers and coefficient values at all nodes on the centerline and two adjacent rows must be entered in this input file. It is not necessary for centerline nodes to correspond to actual piling positions, (i.e., in the cross stream direction), since the overall effect of the pilings on the large scale circulation is all that is being represented. It is important, however, to construct a grid that is as uniform as possible in the vicinity of the bridge. 

===Chezy Friction Coefficient===
'''Nodal attribute name:''' chezy_friction_coefficient_at_sea_floor 
'''Description:''' Chezy friction coefficient. If the user elects to use this nodal attribute, NOLIBF must be set to 1 or the run will terminate. 
'''Requirement:''' Optional. 
'''Units:''' Specified by user. 
'''Values:''' Greater than zero. 
'''ADCIRC Variable:''' ChezyFric''' 

===Eddy Viscosity===
'''Nodal attribute name:''' average_horizontal_eddy_viscosity_in_sea_water_wrt_depth 
'''Description:''' See description [[horizontal eddy viscosity]]. 
'''Requirement:''' Optional. 
'''Units:''' For standard eddy viscosity, units are specified by the user,((length**2)/time). For Smagorinsky-type, unitless. 
'''Values:''' Greater than or equal to zero. 
'''ADCIRC Variable:''' EVC 

===Elemental Slope Limiter===
'''Nodal attribute name:''' elemental_slope_limiter 
'''Description:''' This nodal attribute is used to selectively limit the maximum elevation gradient that can occur across an element, thus improving numerical stability. Alternatively, it is also capable of merely logging individual elements where a specified elemental slope is exceeded at some point during the simulation. When this nodal attribute is loaded, warning messages will be written to the screen and to the fort.16 log file whenever the elevation gradient meets or exceeds the threshold value for the first time at a particular node. When the elemental slope limiter is active at a node, the water surface elevation at that node is reset to the average of the water surface elevations of the surrounding nodes. At the end of the run, a file called ESLNodes.63 will be written to indicate the nodes where the threshold elevation gradient was met or exceeded. Furthermore, If there is an ESLNodes.63 file in the input directory when ADCIRC starts, ADCIRC will load the existing ESLNodes.63 file along with the hotstart file so that the simulation can pick up where it left off, in terms of the elements where the slope is actively limited. When such a simulation finishes, it will overwrite the existing ESLNodes.63 file with a new one that reflects the updated state of limited elemental slopes. 
'''Requirement:''' Optional. 
'''Units:''' length/length or unitless. 
'''Values:''' Zero indicates that slope limiting is always active at that node, because a zero elevation gradient will always be met or exceeded; a positive value indicates the maximum gradient to be allowed at that node, at or beyond which the slope limiter is activated; a negative number indicates that the elevation gradients should be compared to the absolute value of the nodal attribute at this node. In the case of a negative number, ADCIRC will log a warning to the screen and to the fort.16 file the first time the elemental slope is exceeded, but ESLNodes.63 file will not be affected, and the elemental slope limiting will not actually occur at the node. A suggested value for this nodal attribute is 0.001. 
'''ADCIRC Variable:''' elemental_slope_limiter_grad_max 

'''Version Notes:'''
{{ADC version|version=51.47|relation=ge}}
Any activated elemental slope limiter from the previous time step is deactivated and reassessed whether the elevation gradient meets or exceeds the threshold value for the current time step.
{{ADC version|version=51.47|relation=lt}}
Once the elevation gradient is met or exceeded at a node, the elemental slope limiter remains active at that node for the remainder of the ADCIRC run.

===Initial River Elevation===
'''Nodal attribute name:''' initial_river_elevation 
'''Description:''' The initial_river_elevation nodal attribute is used to set the initial water surface elevation at specified nodes. This attribute is functionally identical to the [[Sea Surface Height Above Geoid|<code>sea_surface_height_above_geoid</code>]] attribute, except that any values assigned to elevation-specified boundary conditions in this attribute '''do not''' persist after the start of the simulation. As a result, this attribute is more appropriate for initializing rivers. If both attributes are specified, then the assigned elevation is their sum. Currently, this attribute is only applied if the value supplied at a given node is above zero (i.e. depth less than zero). From cstart.F:
where (River_et_WSE.GT.0.d0)
eta2 = eta2 + River_et_WSE
end where
ADCIRC assumes by default that vertices with negative depths will be dry when the simulation starts. This is, of course, not the case for an inland river whose bed is above mean sea level. This nodal attribute is used in those cases to provide the initial water surface elevation of the river at cold start, and is typically used in conjunction with a flux or elevation [[boundary conditions|boundary condition]] at the inland boundary. See also [[initial conditions]]. 
'''Requirement:''' Optional, but recommended if the domain contains a river with an upstream flux boundary condition and a bed elevation above ADCIRC's starting water elevation (zero unless otherwise specified). 
'''Units:''' Length. 
'''Values:''' Any. 
'''ADCIRC Variable:''' <code>River_et_WSE</code>. 

===[[Internal Tide Energy Conversion]]===
{{ADC version|version=53.01|relation=ge}}
'''Nodal attribute name:''' internal_tide_friction 
'''Description:''' Linear friction term that accounts for energy conversion from barotropic modes to baroclinic modes as surface tides flow over steep and rough topography in the deep ocean generating internal tides. 
'''Requirement:''' Important when simulating tides in computational domains that cover large portions of the deep ocean. 
'''Units:''' 1/sec. 
'''Values:''' Computed through analytical formulations that are spatially dependent on buoyancy frequencies and topographic gradients. 
'''ADCIRC Variable:''' IT_Fric 
'''Note:''' IT_Fric can have 1 (scalar) or 3 (tensor) dimensions. The scalar form dissipates equally in all flow directions. The tensor form dissipates asymmetrically to account for the fact that internal tides are generated as surface tides flow across topographic slopes but not along them. 

===[[Manning's n at sea floor]]===
'''Nodal attribute name:''' mannings_n_at_sea_floor 
'''Description:''' Manning's n. If the user elects to use this nodal attribute, [[NOLIBF]] must be set to 1 or the run will terminate. During execution, the Manning’s n value specified here is converted to an equivalent quadratic friction coefficient before the bottom stress is calculated. The equivalent quadratic friction coefficient is calculated according to the following formula at each node at each time step: Cd(t)=(g*n^2)/cuberoot(depth[+eta(t)]) where depth is the bathymetric depth and [eta(t)] is the water surface elevation. The addition of the water surface elevation is conditional upon the setting of NOLIFA: eta(t) is treated as zero if NOLIFA is set to zero in the fort.15 file. Finally, the value of CF in the fort.15 is used to set a lower limit on the resulting equivalent quadratic friction coefficient, since the Cd calculated from this formula tends to become small in deep water. 
'''Requirement:''' Optional. 
'''Units:''' Specified by user. 
'''Values:''' Greater than zero. 
'''ADCIRC Variable:''' ManningsN 

===Min and Max Primitive Weighting in Continuity Equation===
'''Nodal attribute name:''' min_and_max_primitive_weighting_in_continuity_equation 
'''Description:''' Controls upper and lower bounds on [[TAU0]], which affects numerical damping and stability. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user, 1/time. 
'''Values:''' Information and suggested range supplied in description of [[TAU0]]. 
'''ADCIRC Variable:''' Tau0MinMax 

===Primitive Weighting in Continuity Equation===
'''Nodal attribute name:''' primitive_weighting_in_continuity_equation 
'''Description:''' Related to [[TAU0]], affects numerical damping and stability. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user, 1/time. 
'''Values:''' Information and suggested range supplied in description of [[TAU0]]. 
'''ADCIRC Variable:''' Tau0Var 

===Quadratic Friction coefficient===
'''Nodal attribute name:''' quadratic_friction_coefficient_at_sea_floor 
'''Description:''' See the description of CF in the Model Parameter and Periodic Boundary Condition File. If the user elects to load this from the fort.13 file, [[NOLIBF]] must be set to 1 or the run will terminate. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' Same as CF. 
'''ADCIRC Variable:''' Fric 

===Sea Surface Height Above Geoid===
'''Nodal attribute name:''' sea_surface_height_above_geoid 
'''Description:''' Creates an initial offset of the sea surface from ADCIRC's reference water level (informally, the geoid). If the offset is specified at an elevation boundary such as an open-ocean tidal boundary, it will remain throughout the simulation. Except for that trait, this attribute is functionally identical to the [[initial river elevation|<code>initial_river_elevation</code>]] attribute. Since this attribute does persist along boundaries, it is often used to simulate a steric effect, where water levels are higher in warm seasons because of thermal expansion. See also [[initial conditions]]. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user (length). 
'''Values:''' Any. 
'''ADCIRC Variable:''' <code>GeoidOffset</code> 

=== Surface Canopy coefficient ===
'''Nodal attribute name:''' surface_canopy_coefficient 
'''Description:''' This attribute allows the user to turn off wind stress in heavily forested areas that have been flooded, like a swamp. The canopy shields the water from the effect of the wind. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' Zero if the wind stress should be zero because of a canopy. One otherwise. 
'''ADCIRC Variable:''' VCanopy 

===[[Wind_Stress#Roughness_Reductions|Surface Roughness]]===
'''Nodal attribute name:''' surface_directional_effective_roughness_length 
'''Description:''' A measure of the “roughness” of the land that can impede wind flow and reduce the surface stress that the wind applies. The ocean would be considered very smooth, and skyscrapers would be considered very rough. This attribute is directional, and the twelve values represent the roughness lengths “seen” by winds blowing from twelve different compass directions at each node. The orientation of the twelve values follows the trigonometric convention, that is, zero degrees represents due east, and the values proceed counter clockwise. In other words, the first value at a node is applied to winds blowing from west to east, the second value applies to winds blowing East-Northeast, etc. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user, as is the case for all nodal attributes. The data we use is provided in meters. 
'''Values:''' Greater than or equal to zero. 
'''ADCIRC Variable:''' z0Land 

===Surface Submergence State===
'''Nodal attribute name:''' surface_submergence_state 
'''Description:''' This attribute can force a node to be categorized as dry at the start of the simulation, even if it is below the geoid. This is important for simulating places like New Orleans that are below sea level but are not underwater. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' If set to 1, the node is categorized as dry at the cold start of the simulation. If set to zero, the node is categorized as wet or dry depending on whether its depth is below or above the geoid. 
'''ADCIRC Variable:''' StartDry 

===Wave Refraction in SWAN===
'''Nodal attribute name:''' wave_refraction_in_swan 
'''Description:''' to turn wave refraction on or off in the SWAN calculations during a coupled ADCIRC+SWAN run. In an ADCIRC-only run, this nodal attribute is ignored. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' If set to 1 at a node, wave refraction will be active at that node in the SWAN calculations during a coupled ADCIRC+SWAN run. If set to 0, wave refraction will be deactivated at that node in a coupled ADCIRC+SWAN run. 
'''ADCIRC Variable:''' SwanWaveRefrac 

'''Version Notes:'''
{{ADC version|version=53.00|relation=lt}}
Starting with version v41.01B of SWAN and version 53.00 of ADCIRC, this nodal attribute should no longer be used. See post by Casey Dietrich, [https://ccht.ccee.ncsu.edu/updates-to-spectral-propagation-velocities/ here].

===Absorption-generation Sponge Layer===
'''Nodal attribute name:''' sponge_generator_layer 
'''Description:''' 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' 

[[Category:input files]]
[[Category:nodal attributes]]

Fort.13 file

2020-06-10T16:23:37Z

Jddratli: /* Wave Refraction in SWAN */

The fort.13 file contains nodal attributes, which can vary spatially. For each attribute, one or more values are specified at each node. The number of values and their meaning(s) varies by attribute.

== File Format ==
See [[fort.13 file format]] for details. This file is only read when [[NWP]] > 0 in the Model Parameter and Periodic Boundary Condition File ([[fort.15 file]]).

== Nodal Attributes ==
Note that units for nodal attributes are specified by the user in the fort.13 file, though ADCIRC may require that attributes be supplied in certain units.

===Advection State===
'''Nodal attribute name:''' advection_state 
'''Description:''' The advection_state nodal attribute is used to provide fine grained control over the NOLICA and NOLICAT parameters, so that they can be set on an element-by-element basis. The bathymetric depth at the three nodes of an element are compared to the corresponding nodal attribute values, and if the bathymetric depth at all three nodes is greater than or equal to the corresponding nodal attribute value, the values of NOLICA and NOLICAT will be set to the value indicated in the Model Parameter and Periodic Boundary Condition (fort.15) file. If the bathymetric depth at any of the three nodes of a particular element is less than the corresponding nodal attribute value, the values of NOLICA and NOLICAT will be set to zero on that element. 
'''Requirement:''' Optional. 
'''Units:''' Length. 
'''Values:''' Any. 
'''ADCIRC Variable:''' AdvectionState 

===Bottom Roughness===
'''Nodal attribute name:''' bottom_roughness_length 
'''Description:''' Roughness length for 3D bottom friction calculations. Has no effect on a 2DDI ADCIRC run. 
'''Requirement:''' Optional. 
'''Units:''' Length (m) 
'''Values:''' Greater than zero. A reasonable range for the bottom_roughness_length would be 0.001m -0.2m , (densely vegetated overland values would have an upper limit of about 0.2-0.5m and smooth muddy bottoms could have values as low as 0.0001 m). 
'''ADCIRC Variable:''' Z0b_var 

=== Bridge Pilings Friction Parameters ===
'''Nodal attribute name:''' bridge_pilings_friction_parameters 
'''Description:''' Extra friction from bridge pilings. See Note below. 
'''Requirement:''' Very optional. 
'''Units:''' Vary, see note below and BK, BALPHA, BDELX and POAN. 
'''Values:''' Vary, see note below and BK, BALPHA, BDELX and POAN. 
'''ADCIRC Variable:''' BK, BAlpha, BDelX, POAN 
'''Note:''' Special considerations must be used when designing a grid for an ADCIRC application that includes the effects of bridge pilings. Specifically, it is necessary to build the grid to provide at least three rows of nodes that parallel the bridge span. One row of nodes (centerline nodes) should lie along the approximate centerline of the bridge while the second and third rows of nodes (adjacent nodes) should lie on either side of the centerline nodes in the along steam direction. An initial implementation of obstruction drag in ADCIRC placed this drag entirely at the row of centerline nodes. However, tests showed that this arrangement led to significant oscillations in the numerical solution. The oscillations abated when the obstruction drag was distributed in the along stream direction so that 25 percent was located at each row of adjacent nodes and 50 percent was located at the row of centerline nodes. Node numbers and coefficient values at all nodes on the centerline and two adjacent rows must be entered in this input file. It is not necessary for centerline nodes to correspond to actual piling positions, (i.e., in the cross stream direction), since the overall effect of the pilings on the large scale circulation is all that is being represented. It is important, however, to construct a grid that is as uniform as possible in the vicinity of the bridge. 

===Chezy Friction Coefficient===
'''Nodal attribute name:''' chezy_friction_coefficient_at_sea_floor 
'''Description:''' Chezy friction coefficient. If the user elects to use this nodal attribute, NOLIBF must be set to 1 or the run will terminate. 
'''Requirement:''' Optional. 
'''Units:''' Specified by user. 
'''Values:''' Greater than zero. 
'''ADCIRC Variable:''' ChezyFric''' 

===Eddy Viscosity===
'''Nodal attribute name:''' average_horizontal_eddy_viscosity_in_sea_water_wrt_depth 
'''Description:''' See description [[horizontal eddy viscosity]]. 
'''Requirement:''' Optional. 
'''Units:''' For standard eddy viscosity, units are specified by the user,((length**2)/time). For Smagorinsky-type, unitless. 
'''Values:''' Greater than or equal to zero. 
'''ADCIRC Variable:''' EVC 

===Elemental Slope Limiter===
'''Nodal attribute name:''' elemental_slope_limiter 
'''Description:''' This nodal attribute is used to selectively limit the maximum elevation gradient that can occur across an element, thus improving numerical stability. Alternatively, it is also capable of merely logging individual elements where a specified elemental slope is exceeded at some point during the simulation. When this nodal attribute is loaded, warning messages will be written to the screen and to the fort.16 log file whenever the elevation gradient meets or exceeds the threshold value for the first time at a particular node. When the elemental slope limiter is active at a node, the water surface elevation at that node is reset to the average of the water surface elevations of the surrounding nodes. At the end of the run, a file called ESLNodes.63 will be written to indicate the nodes where the threshold elevation gradient was met or exceeded. Furthermore, If there is an ESLNodes.63 file in the input directory when ADCIRC starts, ADCIRC will load the existing ESLNodes.63 file along with the hotstart file so that the simulation can pick up where it left off, in terms of the elements where the slope is actively limited. When such a simulation finishes, it will overwrite the existing ESLNodes.63 file with a new one that reflects the updated state of limited elemental slopes. 
'''Requirement:''' Optional. 
'''Units:''' length/length or unitless. 
'''Values:''' Zero indicates that slope limiting is always active at that node, because a zero elevation gradient will always be met or exceeded; a positive value indicates the maximum gradient to be allowed at that node, at or beyond which the slope limiter is activated; a negative number indicates that the elevation gradients should be compared to the absolute value of the nodal attribute at this node. In the case of a negative number, ADCIRC will log a warning to the screen and to the fort.16 file the first time the elemental slope is exceeded, but ESLNodes.63 file will not be affected, and the elemental slope limiting will not actually occur at the node. A suggested value for this nodal attribute is 0.001. 
'''ADCIRC Variable:''' elemental_slope_limiter_grad_max 

'''Version Notes:'''
{{ADC version|version=51.47|relation=ge}}
Any activated elemental slope limiter from the previous time step is deactivated and reassessed whether the elevation gradient meets or exceeds the threshold value for the current time step.
{{ADC version|version=51.47|relation=lt}}
Once the elevation gradient is met or exceeded at a node, the elemental slope limiter remains active at that node for the remainder of the ADCIRC run.

===Initial River Elevation===
'''Nodal attribute name:''' initial_river_elevation 
'''Description:''' The initial_river_elevation nodal attribute is used to set the initial water surface elevation at specified nodes. This attribute is functionally identical to the [[Sea Surface Height Above Geoid|<code>sea_surface_height_above_geoid</code>]] attribute, except that any values assigned to elevation-specified boundary conditions in this attribute '''do not''' persist after the start of the simulation. As a result, this attribute is more appropriate for initializing rivers. If both attributes are specified, then the assigned elevation is their sum. Currently, this attribute is only applied if the value supplied at a given node is above zero (i.e. depth less than zero). From cstart.F:
where (River_et_WSE.GT.0.d0)
eta2 = eta2 + River_et_WSE
end where
ADCIRC assumes by default that vertices with negative depths will be dry when the simulation starts. This is, of course, not the case for an inland river whose bed is above mean sea level. This nodal attribute is used in those cases to provide the initial water surface elevation of the river at cold start, and is typically used in conjunction with a flux or elevation [[boundary conditions|boundary condition]] at the inland boundary. See also [[initial conditions]]. 
'''Requirement:''' Optional, but recommended if the domain contains a river with an upstream flux boundary condition and a bed elevation above ADCIRC's starting water elevation (zero unless otherwise specified). 
'''Units:''' Length. 
'''Values:''' Any. 
'''ADCIRC Variable:''' <code>River_et_WSE</code>. 

===[[Internal Tide Energy Conversion]]===
{{ADC version|version=53.01|relation=ge}}
'''Nodal attribute name:''' internal_tide_friction 
'''Description:''' Linear friction term that accounts for energy conversion from barotropic modes to baroclinic modes as surface tides flow over steep and rough topography in the deep ocean generating internal tides. 
'''Requirement:''' Important when simulating tides in computational domains that cover large portions of the deep ocean. 
'''Units:''' 1/sec. 
'''Values:''' Computed through analytical formulations that are spatially dependent on buoyancy frequencies and topographic gradients. 
'''ADCIRC Variable:''' IT_Fric 
'''Note:''' IT_Fric can have 1 (scalar) or 3 (tensor) dimensions. The scalar form dissipates equally in all flow directions. The tensor form dissipates asymmetrically to account for the fact that internal tides are generated as surface tides flow across topographic slopes but not along them. 

===[[Manning's n at sea floor]]===
'''Nodal attribute name:''' mannings_n_at_sea_floor 
'''Description:''' Manning's n. If the user elects to use this nodal attribute, [[NOLIBF]] must be set to 1 or the run will terminate. During execution, the Manning’s n value specified here is converted to an equivalent quadratic friction coefficient before the bottom stress is calculated. The equivalent quadratic friction coefficient is calculated according to the following formula at each node at each time step: Cd(t)=(g*n^2)/cuberoot(depth[+eta(t)]) where depth is the bathymetric depth and [eta(t)] is the water surface elevation. The addition of the water surface elevation is conditional upon the setting of NOLIFA: eta(t) is treated as zero if NOLIFA is set to zero in the fort.15 file. Finally, the value of CF in the fort.15 is used to set a lower limit on the resulting equivalent quadratic friction coefficient, since the Cd calculated from this formula tends to become small in deep water. 
'''Requirement:''' Optional. 
'''Units:''' Specified by user. 
'''Values:''' Greater than zero. 
'''ADCIRC Variable:''' ManningsN 

===Min and Max Primitive Weighting in Continuity Equation===
'''Nodal attribute name:''' min_and_max_primitive_weighting_in_continuity_equation 
'''Description:''' Controls upper and lower bounds on [[TAU0]], which affects numerical damping and stability. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user, 1/time. 
'''Values:''' Information and suggested range supplied in description of [[TAU0]]. 
'''ADCIRC Variable:''' Tau0MinMax 

===Primitive Weighting in Continuity Equation===
'''Nodal attribute name:''' primitive_weighting_in_continuity_equation 
'''Description:''' Related to [[TAU0]], affects numerical damping and stability. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user, 1/time. 
'''Values:''' Information and suggested range supplied in description of [[TAU0]]. 
'''ADCIRC Variable:''' Tau0Var 

===Quadratic Friction coefficient===
'''Nodal attribute name:''' quadratic_friction_coefficient_at_sea_floor 
'''Description:''' See the description of CF in the Model Parameter and Periodic Boundary Condition File. If the user elects to load this from the fort.13 file, [[NOLIBF]] must be set to 1 or the run will terminate. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' Same as CF. 
'''ADCIRC Variable:''' Fric 

===Sea Surface Height Above Geoid===
'''Nodal attribute name:''' sea_surface_height_above_geoid 
'''Description:''' Creates an initial offset of the sea surface from ADCIRC's reference water level (informally, the geoid). If the offset is specified at an elevation boundary such as an open-ocean tidal boundary, it will remain throughout the simulation. Except for that trait, this attribute is functionally identical to the [[initial river elevation|<code>initial_river_elevation</code>]] attribute. Since this attribute does persist along boundaries, it is often used to simulate a steric effect, where water levels are higher in warm seasons because of thermal expansion. See also [[initial conditions]]. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user (length). 
'''Values:''' Any. 
'''ADCIRC Variable:''' <code>GeoidOffset</code> 

=== Surface Canopy coefficient ===
'''Nodal attribute name:''' surface_canopy_coefficient 
'''Description:''' This attribute allows the user to turn off wind stress in heavily forested areas that have been flooded, like a swamp. The canopy shields the water from the effect of the wind. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' Zero if the wind stress should be zero because of a canopy. One otherwise. 
'''ADCIRC Variable:''' VCanopy 

===[[Wind_Stress#Roughness_Reductions|Surface Roughness]]===
'''Nodal attribute name:''' surface_directional_effective_roughness_length 
'''Description:''' A measure of the “roughness” of the land that can impede wind flow and reduce the surface stress that the wind applies. The ocean would be considered very smooth, and skyscrapers would be considered very rough. This attribute is directional, and the twelve values represent the roughness lengths “seen” by winds blowing from twelve different compass directions at each node. The orientation of the twelve values follows the trigonometric convention, that is, zero degrees represents due east, and the values proceed counter clockwise. In other words, the first value at a node is applied to winds blowing from west to east, the second value applies to winds blowing East-Northeast, etc. 
'''Requirement:''' Optional. 
'''Units:''' Specified by the user, as is the case for all nodal attributes. The data we use is provided in meters. 
'''Values:''' Greater than or equal to zero. 
'''ADCIRC Variable:''' z0Land 

===Surface Submergence State===
'''Nodal attribute name:''' surface_submergence_state 
'''Description:''' This attribute can force a node to be categorized as dry at the start of the simulation, even if it is below the geoid. This is important for simulating places like New Orleans that are below sea level but are not underwater. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' If set to 1, the node is categorized as dry at the cold start of the simulation. If set to zero, the node is categorized as wet or dry depending on whether its depth is below or above the geoid. 
'''ADCIRC Variable:''' StartDry 

===Wave Refraction in SWAN===
'''Nodal attribute name:''' wave_refraction_in_swan 
'''Description:''' to turn wave refraction on or off in the SWAN calculations during a coupled ADCIRC+SWAN run. In an ADCIRC-only run, this nodal attribute is ignored. 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' If set to 1 at a node, wave refraction will be active at that node in the SWAN calculations during a coupled ADCIRC+SWAN run. If set to 0, wave refraction will be deactivated at that node in a coupled ADCIRC+SWAN run. 
'''ADCIRC Variable:''' SwanWaveRefrac 

'''Version Notes:'''
{{ADC version|version=53.00|relation=lt}}
Starting with version v41.01B of SWAN and version 53.00 of ADCIRC, this nodal attribute should no longer be used. See post by Casey Dietrich, .

===Absorption-generation Sponge Layer===
'''Nodal attribute name:''' sponge_generator_layer 
'''Description:''' 
'''Requirement:''' Optional. 
'''Units:''' Unitless. 
'''Values:''' 

[[Category:input files]]
[[Category:nodal attributes]]