Model Data Formats

An example NetCDF file containing the essential structure is available here

An IDL program to write NetCDF files with the basic structure is available here

MODEL OUTPUT RESOLUTION: To enable convenient comparison of models and observations, all models are requested to interpolate outputs to the same horizontal grid and resolution. Since our emphasis is on regional and larger scales, use a 1x1 degree grid, centered on lat gridpoints ranging from -40 to 0 degrees (40-0 S) and lon ranging from -110 to -60 degrees (110-60 W). All output should be at 3 hour time resolution, either averaged over 00-03 UTC, 03-06 UTC, etc., or instantaneous at 0130, 0430, etc. This allows good comparison with GEOS and MODIS/A-Train data. Output field dimensions should be lon by lat by height (if applicable) by time, giving a 41 x 41 x nz x 248 dimensional dataset. Use your native model vertical grid.

REQUESTED MODEL OUTPUT: Each model should submit a brief MS Word or plain text documentation file and a netcdf output file. The 1D outputs document your output grid, the 2Dxtime outputs will be used for most of the satellite comparison and comparison with the WHOI stratus buoy at 20S, 85W. The 3D outputs will be used for constructing mean cross sections along 20 W, examining the correlation of leading modes of wind variability with the PBL structure, and looking at aerosol distributions above the boundary-layer top.

Documentation File

The documentation file should include:
D1) the name and email address of the contributor
D2) the official version number and model name
D3) literature reference for your model (if available) plus any major changes made since that reference.
D4) Forecast/analysis approach used to make model output fields
D5) Horizontal model resolution
D6) Number of model vertical levels and corresponding values of sigma.
D7) Timestep
D8) PBL scheme type (e.g. nonlocal surface-forced K-profile, moist TKE, etc.) as you would summarize it in the table of a paper.
D9) Microphysics scheme type
D10) Cloud fraction scheme type
D11) Aerosol scheme type
D12) What form, if any, of aerosol-cloud interaction is included?

Model Output File

The output file, in netcdf format, should include

1D fields:

time [days] since 00Z 1 Oct. 2006
lat [deg N]
lon [deg E]
sigma [0-1] of each model vertical level, averaged over all horizontal gridpoints and times given in the output fill (sigma = p/ps).

2D fields (lon x lat x time):

TS [K] surface radiative skin temperature (= SST over ocean for most models)
ZS [m] surface height (may be less than zero over ocean due to spectral ringing)
land fraction [0-1]
SLP [Pa] - validate against Quikscat/reanalyses
T (10 m) [K] – compare vs. stratus buoy at 20S 85W
q (10 m) [kg/kg] specific humidity – compare vs. stratus buoy at 20S 85W
u (10 m) [m/s] – compare vs. Quikscat and reanalyses
v (10 m )
u (850 hPa) - compare vs. reanalyses
v (850 hPa)
w (850 hPa)
SHF
LHF
Surface momentum fluxes in x and y directions
LWUPTOA, SWUPTOA [W/m2] TOA radiative fluxes. – compare vs. ISCCP
LWDNSFC, SWDNSFC - compare vs. ISCCP and at buoy
WVP - compare vs. SSMI/TMI
LWP - compare vs. TMI/AMSR
CLDLOW - low cloud fraction lcf below 800 hPa – compare vs. ISCCP?
PRECT [kg H20/(m2-s)] surface precipitation.
AOD [0-1] Aerosol optical depth

For the remaining three fields, we assume the layers are numbered from the top, so k = 1 is the top level. We let LWPica(k) be the integrated grid-box liquid water path including and above layer k. Use only liquid to exclude ice cloud. Define a cloud weighting function cwf(k) = lcf*ncwf(k), k = 1,…nz, where ncwf(k) = exp(-K*LWPica(k-1)) – exp(-K*LWPica(k)) and LWPica(k) is the integrated grid-box liquid water path above and including layer k. Here K = 156/lcf in units of m^2/kg. We let the surface cloud weighting function cwf(nz+1) = 1 – (cwf(1)…+cwf(nz)).

TCLDTOP [K] low cloud IR brightness temperature proxy
TBBCLD = cwf(nz+1)*Ts + sum k = 1 to nz of cwf(k)*T(k)
ZCLDTOP [m] low cloud height proxy
ZCLDTOP = (sum k = 1 to nz of cwf(k)*z(k))/ (1 – cwf(nz+1))
REFFTOP [um] effective radius proxy
REFFTOP = (sum k = 1 to nz of cwf(k)*reff(k))/ (1 – cwf(nz+1))
NDTOP [/cm3] cloud droplet concentration
NDTOP = (sum k = 1 to nz of cwf(k)*ND(k))/ (1 – cwf(nz+1))

3D Fields:

T
qv
ql+qi,
cf
reff
u, v, w
Aerosol masses:
SO4/HSO4, BC, OC, Seasalt
Aerosol precursor mass mixing ratios:
DMS [atmospheric], MSA, SO2, H2SO4, DMS [ocean], organics?
Oxidants and oxidant related:
H2O2, O3, OH

Please email robwood@atmos.washington.edu for clarification or further details