CAVE - Available FTP Data

CAVE archives surface observations and collocated TOA CERES observations and SARB model calculations. This data base, which is used for our validation is made freely available via anonymous ftp. The following table outlines accessible data sets.

CAVE Surface Observations

Observations of surface fluxes (and more) have been collected from over 40 surface sites around the globe. All adhere to strict BSRN calibration standards. Data are received in original format and averaged to 15 minute means. When available ancillary data are added to the files, such as AERONET aerosol optical depths, meteorological observations etc. Also included if possible is an estimate of cloud fraction based on the ShortWave Flux (SWF) Algorithm of Long & Ackermen (1999?). Data is provided for each site, one file per month. Data has been collected beginning in Jan 1998 and continues today. Goto SAMPLOT to see summaries of the files and to plot observations.

CAVE Surface Observations "Synoptic (SYN)" Averages

These files contain longer temporal averages of the CAVE surface flux observation files. The list of variables in each file is the same except that each file now has packed into it, 1 Hour, 3 Hour, Daily, and Monthly Averages, standard deviations and sample number included for each site for each month. Again, to see a listing of variables available for each file goto: SAMPLOT.

CERES Clouds & Radiative Flux Data Product

The Clouds & the Earths Radiant Energy System (CERES) instrument on board Terra and Aqua produce a number of archived data products. The CERES Surface and Atmospheric Radiation Budget (SARB) working group is tasked with calculating heating rate profiles beneath TOA CERES observations. These radiation transfer calculations (along with CERES TOA observations and a number of model inputs) are archived in the CERES Clouds & Radiative Swath (CRS) data product.

For our purposes we subset the CRS data product for footprints collocated within 25km of the CAVE surface observations sites. These subset CRS data are made available in this ftp directory.

FSW TOA & Surface Albedo

The "Fixed Swath Width" (FSW) CERES data product takes the CRS product, explained above, and averages these values into 1 Degree, Equal Angle, grid boxes at the time of satellite observations. We have taken these (approximately) twice daily gridded averages and averaged them over a month. This produces "monthly mean" values in the sense that they are averages at the times of CERES observations. not averages over all hours of a month.

When the radiation transfer model is run, it is run without clouds for each footprint. This supplies a "clear sky" profile of fluxes whether or not there are clouds in the footprint. We have calculated albedo from the upward/downward surface fluxes from these clear sky model runs giving global "clear sky" albedo monthly mean maps for 5+ years (Mar 2000 through May 2005) and made them available via anonymous ftp.

Atmospheric Profiles (GEOS4)

To calculate the flux profiles beneath CERES footprints globally it is necessary to define the atmospher globally for the lifespan of CERES observations. This has been done using the Goddard Modeling and Assimilation Office (GMAO) GEOS-4 4-d data assimilation data product. The product is 6 hourly and has a spatial resolution of 1 degree. For CAVE we have extracted the profiles from the grid box containing the CAVE surface site and interpolated the 6 hourly profiles to 1/2 hour using linear interpolation. These data are made available in the MOA_GEOS/ directory.

MODIS Surface BRDF Coefficients

The MODIS MOD43C2 0.05degree equal angle gridded BRDF coefficients were extracted for 8 MODIS files for 2 Degree regions centered on the CAVE surface sites. These data and fortran programs that can be used to convert the BRDF coefficients to surface albedo are made available here.