Information About the National Water Model

Output File Contents

Content of output files varies by forecast configuration (internal NetCDF variable names and units are given in parenthesis). Select a forecast configuration and file type to view related variable definitions and names.


Analysis and Assimilation

1Km gridded NetCDF
  • Near surface soil moisture saturation 40cm thickness (soilsat_top, fraction)
  • Accumulated ET (accet, mm)
  • Snow temperature - column integrated (snowt_avg, degrees K)
  • Column averaged snow cover fraction (fsno, fraction)
  • Snow water equivalent (sneqv, kg/m2)
  • Snow depth (snowh, m)
250m gridded NetCDF
  • Ponded water depth (sfcheadsubrt, mm)
  • Depth to soil saturation (zwattablrt, m)
Point-type Channel NetCDF
  • Streamflow (streamflow, m3/sec)
  • Streamflow data assimilation increment (nudge, m3/sec)
  • Stream velocity (velocity, m/s)
  • Channel inflow (q_lateral, m3/sec)
Point-type Reservoir NetCDF
  • Reservoir water surface elevation (elevation, m)
  • Reservoir inflow (inflow, m3/sec)
  • Reservoir outflow (outflow, m3/sec)

Short-range

1Km gridded NetCDF
  • Near surface soil moisture saturation 40cm thickness (soilsat_top, fraction)
  • Accumulated ET (accet, mm)
  • Snow temperature - column integrated (snowt_avg, degrees K)
  • Column averaged snow cover fraction (fsno, fraction)
  • Snow water equivalent (sneqv, kg/m2)
  • Snow depth (snowh, m)
250m gridded NetCDF
  • Ponded water depth (sfcheadsubrt, mm)
  • Depth to soil saturation (zwattablrt, m)
Point-type Channel NetCDF
  • Streamflow (streamflow, m3/sec)
  • Streamflow data assimilation increment (nudge, m3/sec)
  • Stream velocity (velocity, m/s)
  • Channel inflow (q_lateral, m3/sec)
Point-type reservoir NetCDF
  • Reservoir water surface elevation (elevation, m)
  • Reservoir inflow (inflow, m3/sec)
  • Reservoir outflow (outflow, m3/sec)

Medium-range

1Km gridded NetCDF
  • Accumulated underground runoff (ugdrnoff, mm)
  • Accumulated snowmelt (acsnom, mm)
  • Snow depth (snowh, m)
  • Snow water equivalent (sneqv, kg/m2)
  • Total canopy water storage (canwat, mm)
  • Accumulated canopy evaporation (accecan, mm)
  • Accumulated transpiration (accetran, mm)
  • Accumulated direct soil evaporation (accedir, mm)
  • Snow layer liquid water (snliq, mm)
  • Number of snow layers (isnow)
  • Soil temperature on native layers (soil_t, degrees K)
  • Snow temperature - column integrated (snowt_avg, degrees K)
  • Snow cover fraction (fsno, fraction)
  • Volumetric soil moisture on native layers (soil_m, m3/m3)
  • Near surface soil moisture defiict, 40cm thickness (soilsat_top, fraction)
  • Soil ice fraction - column integrated (soilice, fraction)
  • Accumulated evapotranspiration (accet, mm)
  • Ground heat flux (grdflx, w/m2)
  • Sensible heat flux (hfx, w/m2)
  • Latent heat flux (lh, w/m2)
  • Net longwave flux (fira, w/m2)
  • Net shortwave flux (fsa, w/m2)
  • Surface radiative temperature (trad, degrees K)
250m gridded NetCDF
  • Ponded water depth (sfcheadsubrt, mm)
  • Depth to soil saturation (zwattablrt, m)
Point-type Channel NetCDF
  • Streamflow (streamflow, m3/sec)
  • Streamflow data assimilation increment (nudge, m3/sec)
  • Stream velocity (velocity, m/s)
  • Channel inflow (q_lateral, m3/sec)
Point-type reservoir NetCDF
  • Reservoir water surface elevation (elevation, m)
  • Reservoir inflow (inflow, m3/sec)
  • Reservoir outflow (outflow, m3/sec)

Long-range

1Km gridded NetCDF
  • Underground runoff (ugdrnoff, mm)
  • Surface runoff (sfcrnoff, mm)
  • Accumulated snowmelt (acsnom, mm)
  • Snow water equivalent (sneqv, kg/m2)
  • Total column soil moisture saturation (soilsat, fraction)
  • Total canopy water storage (canwat, mm)
  • Near surface soil moisture saturation, 40cm thickness (soilsat_top, fraction)
  • Accumulated evapotranspiration (accet, mm)
250m gridded NetCDF
  • None
Point-type Channel NetCDF
  • Streamflow (streamflow, m3/sec)
  • Streamflow data assimilation increment (nudge, m3/sec)
Point-type reservoir NetCDF
  • Reservoir water surface elevation (elevation, m)
  • Reservoir inflow (inflow, m3/sec)
  • Reservoir outflow (outflow, m3/sec)

Forcing Data

All of the preceding analysis and forecast configurations require the same set of 1Km forcing variables: precipitation rate, surface pressure, shortwave radiation, longwave radiation, u-wind, v-wind, temperature, and some humidity, but, as outlined above, these fields come from different sources for each model configuration. A selection of forcing files are disseminated alongside the model analysis and short/medium forecast output.

  • 2 meter temperature (t2d, degrees K)
  • 2 meter specific humidity (q2d, kg/kg)
  • 10 meter U wind component (u2d, m/sec)
  • 10 meter V wind component (v2d, m/sec)
  • Surface pressure (psfc, Pa)
  • Downward shortwave radiation (swdown, w/m2)
  • Downward longwave radiation (lwdown, w/m2)
  • Precipitation rate (rainrate, kg/m2sec)