AOSN-II Hourly Water Flux from 3km COAMPS: 4 August - 7 September 2003

COAMPS analysis and 72 hour forecast fields received from on a twice a day basis were used to generate forcings for AOSN-II HOPS runs. The COAMPS fields were available on four different resolution lambert conformal projection COAMPS grids and included:

Hourly Water Flux

airtmp_zht (2 m air temperature (C) )
dataht_sfc (data information file)
grdtmp_sfc (surface temperature (K) over land and water)
lahflx_sfc (surface latent heat flux w/m**2)
lndsea_sfc (land sea table - Note that the "water pts=0" and "land pts=1")
lonflx_sfc (longwave radiation at surface w/m**2)
relhum_zht (relative humidity at 2 m per cent)
seatmp_sfc (sea surface temperature)
sehflx_sfc (surface sensible heat flux W/m**2)
slpres_ml (sea level pressure hPa)
solflx_sfc (shortwave radiation at sfc w/m**2)
stresu_sfc (u component of surface stress N/m**2)
stresv_sfc (v component of surface stress N/m**2)
ttlpcp_sfc (total precipitation mm)
uuwind_zht (u component of 10-m wind m/s)
vvwind_zht (v component of 10-m wind m/s)
wstres_sfc (total surface stress N/m**2)

The net surface water flux (E-P) was calculated in cm/day, with positive as net evaporation. Total evaporation was calculated lahflx_sfc and airtmp_zht as follows: Compute evaporation [kg m-2 sec-1]:
vl = (2.5008e+6) - (2.3e+3)*atmp;
[vl is latent heat of evaporation (J kg-1)]
evap = -qlat./vl;
Next, convert evap. (kg m-2 sec-1 to cm/day)
Total precipitation was obtained by just converting ttlpcp_sfc (total precipitation mm in 12 hours) to cm/day.

The plots are nowcasts at hourly intervals from 4 August - 7 September 2003. Each day begins at 0000Z (1700 PDT). The plots have varying contours to allow for structures to appear.