DYCOMS-II Model: NCEP 00 UTC AVN 48 Hour Forecast Data (binary) 1.0 General Information The NCEP 00 UTC AVN 48 Hour Forecast Data is one of several model data sets collected by the University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS) as part of the Dynamics and Chemistry of Marine Stratocumulus Phase II: Entrainment Studies (DYCOMS-II) project. The data include NCEP 00 UTC AVN 48 hour forecast data for 20 grid points (nine of which are associated with DYCOMS). The data cover the period from 1 - 31 July 2001 and are available once per day at 00 UTC. The data were acquired from the National Oceanic and Atmospheric Administration (NOAA)/National Centers for Environmental Predication (NOAA). These data are in binary files. 2.0 Data Contact Bjorn Stevens, UCLA (bstevens@atmos.ucla.edu) Steve Krueger, University of Utah (skrueger@met.utah.edu) Hua-Lu Pan, NCEP (hpan@ncep.noaa.gov) 3.0 Data and Format Information 3.1 File Types The NCEP data comes in one single binary file with a name of the form armavn.200107DD where DD is the day. 3.2 Grid Points Each file contains data for 20 grid points, these are respectively: 1. ARM SGP CF 36.609 N 97.485 W 313 m (SGP CF = Southern Great Plains Central Facility) bounding lat/lons of the SGP SCM analysis grid are: north south east west lat: 38.05N 35.35N lon: 95.85 W 98.70 W 2. TWP - Manus 2.060 S 147.425 E 6 m 3. TWP - Nauru 0.521 S 166.916 E a few m 4. NSA - Barrow 71.30 N 156.68 W 10 m (TWP = Tropical Western Pacific) (NSA = North Slope of Alaska) 5. Porto Santo. Madiera Is. (33 N, 16 W). This site is in the stratocumulus to cumulus transition zone: Ocean Weather Ship radiosonde data exist for these locations: 6. Subtropical cold advection regime (30 N, 140W) 7. A subtropical warm advection regime (34 N, 164 E) 8. A midlatitude oceanic regime, (52.75 N, 35.5W) The first of these is another stratocumulus to cumulus transition location. 9. Arctic ocean 77.00 N 158 W 10. TOGA COARE IFA 2.00 S 155 W 11. Amazon basin 10.88 S 62.6 W 12.-20. DYCOMS-2 (subtropical cold advection regime) lat,lon: 29.8200 -123.050 lat,lon: 29.8200 -121.640 lat,lon: 29.8200 -120.230 lat,lon: 31.2300 -123.050 lat,lon: 31.2300 -121.640 lat,lon: 31.2300 -120.230 lat,lon: 32.6300 -123.050 lat,lon: 32.6300 -121.640 lat,lon: 32.6300 -120.230 3.3 File Content and Format This file contains the description of the mrf station data derived from the MRF-AVN runs intended for ARM single model comparison and other uses of the column models. record 1 ... 12 integers hour (e.g.00) month (e.g.11) day (e.g.7) year (e.g.2000) # of surface variables (e.g. 25) # of flux variables (e.g.29) nvar # of variables for each sounding (e.g.7) levs # of vertical levels for each sounding (e.g.42) npoint # of station points (e.g.50) starting forecast hour (e.g.0) ending forecast hour (e.g.48) forecast output step (e.g.3) record 2 ... vertical sounding levels (real*4) sigi(levs+1), sigl(levs) where sigi denotes the interface and sigl the model levels All vertical level variables start from the near surface level the following are looped over # of station points and forecast time record 3 ... surface variables (real*4) latitude of station (degree) longitude of station (degree) zsfc (model surface height for the station) (m) psfc (model surface pressure for the station) (Pa) dpsdt (surface pressure tendency) (Pa/sec) tsfc (model surface temperature) (K) soilm1 (first soil layer volumetric water content) () soilm2 (second soil layer volumetric water content) () snow (water equivalent snow depth) (m) soilt1 (first soil layer temperature) (K) soilt2 (second soil layer temperature) (K) soilt3 (third soil layer temperature, fixed for time) (K) z0 (model surface roughness length) (cm) cv (model convective cloud fraction) () cvb (model convective cloud base pressure) (?) cvt (model convective cloud top pressure) (?) albedo1 (one of four albedo used in the model) () albedo2 (one of four albedo used in the model) () albedo3 (one of four albedo used in the model) () albedo4 (one of four albedo used in the model) () slimsk (sea(0) land(1) and ice(2) flag) vegfrac (model vegetation fraction) () f10m (model 10-meter to sigma level1 similarity profile ratio) () canopy (canopy water content) (m) vegtype (vegetation type 1-13) () soiltype (soil type 1-9) () vegfrac1 (vegfrac type 1 used in radiation) vegfrac2 (vegfrac type 2 used in radiation) record 4 ... flux type variables (real*4) lsmask (land(0) sea(1) mask) ustress (stress in zonal direction) (N/m**2) vstress (stress in meridional direction) (N/m**2) shf (sensible heat flux) (W/m**2) lhf (latent heat flux) (W/m**2) dlws (downward long wave flux at surface) (W/M**2) ulws (upward long wave flux at surface) (W/M**2) ulwt (upward long wave flux at toa) (W/M**2) uswt (upward short wave flux at toa) (W/M**2) usws (upward short wave flux at surface) (W/M**2) dsws (downward short wave flux at surface) (W/M**2) cldh (high cloud fraction) () cldm (mid cloud fraction) () cldl (low cloud fraction) () precip (precipitation accumulated between outputs) (m) cnvprc (conv precipitation accumulated between outputs) (m) gflx (ground heat flux) (W/m**2) u10 (model derived 10-meter zonal wind) (m/s) v10 (model derived 10-meter meridional wind) (m/s) t2 (model derived 2-meter temperature) (K) q2 (model derived 2-meter specific humidity) (g/g) psfc (surface pressure again) (hPa) tmax (maximum temp between outputs) (K) tmin (minimum temp between outputs) (K) ugrw (zonal stress due to gravity wave drag) (W/m**2) vgrw (meridional stress due to gravity wave drag) (W/m**2) hpbl (model diagnosed planetary boundary layer depth) (m) albedo (effective model albedo..derived) () cldpbl (boundary layer cloud fraction) () All records that follows are real*4 record 5 ... levs of model zonal wind velocity (m/s) record 6 ... levs of model meridional wind velocity (m/s) record 7 ... levs of model temperature (K) record 8 ... levs of model specific humidity (g/g) record 9 ... levs of model pressure (mili Pa) if(nvar.gt.5) record 10 ... levs of model derived omega (mili pa/sec) record 11 ... levs of model derived dtdt (K/sec) record 12 ... levs of model derived dqdt (g/g/sec) if(nvar.gt.8) record 13 ... levs of dqcdt (g/g/sec) if(nvar.gt.9) record 14 ... ozone mixing ratios loop over npoint loop over time NOTE NOTE NOTE .. the strange units of the pressure and omega data (records 9 and 10) was due to a processing error. 4.0 Quality Control Procedures UCAR/JOSS conducted no quality checks on these data. 5.0 File Naming Convention The file names are structured as follows: armavn.yyyymmddhh Where armavn is the data type yyyy is the four digit year mm is the two digit month dd is the two digit day hh is the hour (UTC) 6.0 References None.