VIC Forcing File¶
The VIC Image Driver requires a NetCDF file with gridded subdaily forcings. The required forcing variables and units are listed below and must also be specified in the Global Parameter File:
Meteorological Forcings, Required in all simulations:¶
Variable | Description | Units |
---|---|---|
AIR_TEMP | Average air temperature | C |
PREC | Total precipitation (rain and snow) | mm |
PRESSURE | Atmospheric pressure | kPa |
SWDOWN | Incoming shortwave radiation | W/m2 |
LWDOWN | Incoming longwave radiation | W/m2 |
VP | Vapor pressure | kPa |
WIND | Wind speed | m/s |
The forcing data must be chunked by calendar year, with each NetCDF file named by the year, e.g. prefix.$year.nc
.
Example output from ncdump -h Stehekin_image_test.forcings_10days.1949
should look like this:
netcdf Stehekin_image_test.forcings_10days.1949 {
dimensions:
time = 240 ;
lon = 5 ;
lat = 4 ;
variables:
int time(time) ;
time:units = "hours since 1949-01-01" ;
time:calendar = "proleptic_gregorian" ;
double lon(lon) ;
lon:standard_name = "longitude" ;
lon:long_name = "longitude of grid cell center" ;
lon:units = "degrees_east" ;
lon:axis = "X" ;
double lat(lat) ;
lat:standard_name = "latitude" ;
lat:long_name = "latitude of grid cell center" ;
lat:units = "degrees_north" ;
lat:axis = "Y" ;
double mask(lat, lon) ;
mask:_FillValue = 0. ;
mask:comment = "0 value indicates cell is not active" ;
mask:long_name = "fraction of grid cell that is activedomain mask" ;
mask:note = "unitlessunitless" ;
float prcp(time, lat, lon) ;
prcp:_FillValue = 9.96921e+36f ;
prcp:long_name = "PREC" ;
prcp:column = 0 ;
prcp:units = "mm/step" ;
prcp:description = "PREC" ;
float tas(time, lat, lon) ;
tas:_FillValue = 9.96921e+36f ;
tas:long_name = "AIR_TEMP" ;
tas:column = 1 ;
tas:units = "C" ;
tas:description = "AIR_TEMP" ;
float dswrf(time, lat, lon) ;
dswrf:_FillValue = 9.96921e+36f ;
dswrf:long_name = "SWDOWN" ;
dswrf:column = 2 ;
dswrf:units = "W/m2" ;
dswrf:description = "SWDOWN" ;
float dlwrf(time, lat, lon) ;
dlwrf:_FillValue = 9.96921e+36f ;
dlwrf:long_name = "LWDOWN" ;
dlwrf:column = 3 ;
dlwrf:units = "W/m2" ;
dlwrf:description = "LWDOWN" ;
float pres(time, lat, lon) ;
pres:_FillValue = 9.96921e+36f ;
pres:long_name = "PRESSURE" ;
pres:column = 5 ;
pres:units = "kPa" ;
pres:description = "PRESSURE" ;
float vp(time, lat, lon) ;
vp:_FillValue = 9.96921e+36f ;
vp:long_name = "VP" ;
vp:column = 6 ;
vp:units = "kPa" ;
vp:description = "VP" ;
float wind(time, lat, lon) ;
wind:_FillValue = 9.96921e+36f ;
wind:long_name = "WIND" ;
wind:column = 7 ;
wind:units = "m/s" ;
wind:description = "WIND" ;
// global attributes:
:title = "Stehekin 10-day example (19490101-19490110)" ;
:history = "Created: Fri May 6 09:34:06 2016 by ymao" ;
:institution = "University of Washington" ;
:source = "/home/ymao/.conda/envs/vic5/bin/vic_utils" ;
:references = "Primary Historical Reference for VIC: Liang,X., D. P. Lettenmaier, E. F. Wood, and S. J. Burges,1994: A Simple hydrologically Based Model of LandSurface Water and Energy Fluxes for GSMs, J. Geophys.Res., 99(D7), 14,415-14,428." ;
:comment = "Output from the Variable Infiltration Capacity(VIC) Macroscale Hydrologic Model" ;
:conventions = "CF-1.6" ;
:hostname = "compute-0-2.local" ;
:username = "ymao" ;
:version = "VIC.4.2.b" ;
:grid = "BPA Grid" ;
}
Non-meteorological Forcings¶
Documentation for vegetation, lake and carbon cycle forcings will be added at a later date.