ADCIRC User Manual

Single File Meteorological Forcing Input (fort.22)

A single meteorological input file (wind velocity and atmospheric pressure) is read when NWS= 1, 2, -2, 3, 4, -4, 5, -5, 6, 101, 102, -102, 103, 104, -104, 105, -105, 106 in the Model Parameter and Periodic Boundary Condition File. See notes at the end of this section for additional information on the contents of this file.

The spatial extents of the meteorological 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 basic file structure is shown below. Each line of input data is represented by a line containing the input variable name(s) in bold face type. Blank lines are only to enhance readability. Loops indicate multiple lines of input. Conditional input is indicated by an if clause. Definitions of each variable are provided via hot links.

If NWS = 1 or 101
for k=1,NP
JN, WSX(k), WSY(k), PRN(k,j)
end k loop

If NWS = 2, -2, 102 or -102
for k=1, NP
JN, WSX(k), WSY(k), PRN(k,j)
end k loop

If NWS = 3 or 103
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

If NWS = 4, -4, 104 or -104
JN, WVNX(JN), WVNY(JN), PRN(k,j)
……………………………………..
……………………………………..
……………………………………..

If NWS = 5, -5, 105, or -105
for k = 1, NP
JN, WVX(k), WVY(k), PRN(k,j)
end k loop

If NWS = 6 or 106
for k=1, NWLAT
for j=1, NWLON
WVXFN(k,j), WVYFN(k,j)PRN(k,j)
end j loop
end k loop

If NWS = 8 or 9 use the ATCF Best Track/Objective Aid/Wind Radii Format.

If NWS = 10
for k=1, LONB*LATB
PG(k), UG(k), VG(k)
end j loop

If NWS = 11
for k=1, LONB*LATB
PG(k), UG(k), VG(k)
end j loop

General Note:

Meteorological data must be provided for the entire model run, otherwise the run will crash!!!

Notes for NWS = 1, 101

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

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

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.

Notes for NWS = 2, -2, 102 or -102

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

If NWS = 2 or 102, the first set of met. data corresponds to TIME=STATIM. If NWS = -2 or –102, the first set of met data corresponds to TIME=HOT START TIME. Additional sets of met. data must be provided every WTIMINC, where WTIMINC 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.

Notes for NWS = 3, 103 - US Navy Fleet Numeric format

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 WTIMINC, where WTIMINC is the met. data time interval. Values for NWLAT, NWLON, WTIMINC, 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.

WIND_SPEED = magnitude of WIND_VEL

DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)

If (DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003

WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED

Notes for NWS = 4, -4, 104 or -104 - 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.

If NWS = 4 or 104, the first set of met. data corresponds to TIME=STATIM. If NWS = -104 or -4, the first set of met data corresponds to TIME=HOT START TIME. Additional sets of met. data must be provided every WTIMINC, where WTIMINC 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:

WIND_VEL{m/s @ 10m} = WIND_VEL{knots @ bl average}*0.5144 (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).

WIND_SPEED = magnitude of WIND_VEL

DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)

if(DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003

WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED

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

PRESSURE{m H2O}=PRESSURE{Pa/100}*100/(GRAVITY*DENSITY H2O).

Notes for NWS = 5, -5, 105, -105

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 NWS = 5 or 105, the first set of met. data corresponds to TIME=STATIM. If NWS = -105 or -5, the first set of met data corresponds to TIME=HOT START TIME. Additional sets of met. data must be provided every WTIMINC, where WTIMINC 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:

WIND_SPEED = magnitude of WIND_VEL

DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)

if(DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003

WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED

Notes for NWS = 6, 106

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 (k=1) to south (k=NWLAT) and x (e.g., longitude) varies from west (j=1) to east (j=NWLON). 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 meterological 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 TIME=STATIM. If the model is hot started, this corresponds to TIME=HOT START TIME. Additional sets of met. data must be provided every WTIMINC, where WTIMINC is the met. data time interval. Values for NWLAT, NWLON, WTIMINC, 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 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.

WIND_SPEED = magnitude of WIND_VEL

DRAG_COEFF = 0.001*(0.75+0.067*WIND_SPEED)

If (DRAG_COEFF.gt.0.003) DRAG_COEFF=0.003

WIND_STRESS = DRAG_COEFF*0.001293*WIND_VEL*WIND_SPEED

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

PRESSURE{m H2O}=PRESSURE{Pascal}/(GRAVITY*DENSITY H2O).

Notes for NWS = 8

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 assumed to correspond to the ATCF Best Track/Objective Aid/Wind Radii Format. Historical tracks, real-time hindcast tracks and real-time forecast tracks may be found in this format. Selecting NWS = 8 also requires the specification of the cold start time, storm number, and boundary layer adjustment (see YYYY MM DD HH24 StormNumber BLAdj). Garret's formula is used to compute wind stress from the wind velocity.

Notes for NWS = 9

Hurricane Parameters are read in from the Single File Meteorological Forcing Input File. It is assumed that the first entry in the Single File Meteorological Forcing Input File corresponds to the beginning of the model run (e.g., the cold start time). 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 ATCF Best Track/Objective Aid/Wind Radii Format. 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.
In order to use the NWS=9 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: http://www.nrlmry.navy.mil/atcf_web/docs/database/new/abrdeck.html
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 NWS=9 option requires the following variables in the fort.22 file in a best track format:
1) Forecast time in hours (column 6); enter the time in hours in each record starting at 0
2) Latitude of the eye (column 7)
3) Longitude of the eye (column 8)
4) Maximum sustained wind speed in knots (column 9)
5) Minimum sea level pressure in MB (column 10)
6) Wind intensity in knots of the radii defined in the record (34, 50, 64 or 100 knots) (column 12)
7) Radius of specified wind intensity for quadrants 1, 2, 3, 4 in NM (columns 14, 15, 16, 17); ≠ 0
8) Background pressure in MB (column 18); a standard value of 1013 can be used
Below is a sample fort.22 file and the columns that are required:

Required columns: 6 7 8 9 10 12 14 15 16 17 18

AL, 13, 2003090800,   , ASYM,   0, 158N, 397W, 80, 976, HU, 34, NEQ,   80,   80,   80,   80, 1013, 220, 25,   0,   0, ...
AL, 13, 2003090806,   , ASYM,   6, 165N, 409W, 95, 966, HU, 34, NEQ,   90,   90,   90,   90, 1013, 220, 25,   0,   0, ...
AL, 13, 2003090812,   , ASYM, 12, 171N, 420W, 110, 952, HU, 34, NEQ,   90,   90,   90,   90, 1013, 220, 25,   0,   0, ...
AL, 13, 2003090818,   , ASYM, 18, 176N, 431W, 110, 952, HU, 34, NEQ, 120, 100, 100, 120, 1013, 220, 25,   0,   0, ...
AL, 13, 2003090900,   , ASYM, 24, 182N, 441W, 115, 948, HU, 34, NEQ, 120, 100,   75, 120, 1013, 200, 25,   0,   0, ...

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