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CAVE: Clouds & Radiative Swath
(CRS) Data

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CAVE Clouds & Radiation Swath (CRS) files contain a modified version of the official CERES CRS data product that one may access from the NASA Langley Atmospheric Sciences Data Center These files contain footprint by footprint observations and radiation transfer calculations for every other CERES footprint and every other CERES scan. For our purposes the files here contain only those footprints whose radiometric center lies within a 25km radius of surface validation sites (list of surface validation sites) which are observing radiation coming down at the surface of the Earth.

The following table contains links to details explaning the files.

Link Description Example
Summary Summary of CERES Clouds & Radiative Swath (CRS) data product. ----------
Site List A complete list of locations where subset CRS is available from the CAVE data base. ----------
File availability Quick search for available months for a given site.
(See site list for a listing of all CAVE surface sites.)
3 Letter Identifier:
TERRA AQUA
File Format 1 File Per site/Per Month
Explains the format of the binary file		 ----------
File Naming Conventions How file names are defined and
directory paths at FTP site.		 SURFRAD Example
Read Routines Fortran 90 and IDL code to read binary SAM Files. Fortran Code
Referencing Data Please reference data used appropriately. ----------
     
Access ftp
data base		 Access ftp data base via the web from this link. Data

Summary

The CERES instruments on board TRMM, Terra, and Aqua satellites observe emitted and reflected radiation at the top of the Earth's atmosphere. Beyond these observations CERES produces "higer order" data products that synthasize other inputs, for instance MODIS radiances collocated within a given CERES footprint observation. The first higher order product, the Single Satellite Flux (SSF product) provides, along with CERES observed radiances and fluxes, cloud, aerosol and surface properties defined to be contained within the bounds of the CERES footprint, ~20km to ~30km at the Earth's surface, in length, near nadir viewing angles. Utilizing the CERES SSF product, the Surface & Atmospheric Radiation Budget (SARB) group, adds in yet more ancillary data (for instance gridded meteorological profile data supplying temperature, pressure, and humidity data) and then execute a fast radiation transfer code under a number of different scenarious. (See table below.) Radiation transfer results are output at 5 atmosperhic pressure levels, though the model is run at much higher vertical resolution. After the 4 scenarios are run the model TOA reuslults are compared to the CERES observed TOA fluxes and radiances. Depending on scene conditions, various inputs are carefully adjusted and the model is run again. This provides constrained (or "tuned") model calculations and it is these tuned values, along with the amount by which they were adjusted, which are reported in the CRS files. These tuned fluxes and adjustments and a number of RT inputs are basically added to the SSF record for each footprint and released as the next higher order data product, the Clouds & Radiative Swath or CRS data product.

Model Run Description
Pristine Atmospheric profile only, no clouds, no aerosols.
Clear Sky Atmospheric profile & aerosols, no clouds.
All Sky Run includes atmospheric profile & aerosols & clouds.
Clouds, No Aerosol Run includes atmospheric profile & cloud information, excludes aerosol.

Links to Official CERES CRS documentation.
Data products catalog Lists of variables TRMM PFM (Edition 2A)
TERRA FM1 & FM2 (Edition 2B)
Data Quality Summary Important summary of issues/problems in data files. FM1 & FM2, Edition 2B
Algorithm & Theoretical Basis
Document (ATBD)		 Original algorithm description (dated 1997) PDF
Collection Guide Variable definitions. Not yet available. See table below. PDF

CERES Clouds & Radiation Swath (CRS) - The CAVE Version

The CAVE CRS file is a binary (big-endian) file of fixed record length. It consists of a Header record that contains information regarding the surface site and a list of variables contained in each file. The remainder of a file contains one record for each available variable where each record is one month's worth of data for that variable. Figure 1 below shows this schematically.

SSF Listing
CRS Listing
Derived Variables
Figure 1. Graphic showing Surface Aerosol Meteorology (SAM)
file structure.

File Naming Conventions and Directory Paths at FTP Site

CRS files can be downloaded via anonymous FTP from www-cave.larc.nasa.gov then "cd" to public/cave/CRS/TERRA. File are contained in subdirectories defined by data source. File names are dependent upon a unique 3-letter identifier for each site. See Site List for a global map and listing of all surface sites. Or just continue down to see a list of sites, their directory paths at the FTP site and their file names.

File names are based on a set of unique 3-letter identifiers, the directory path at the FTP site is based on the data source as shown in the following table.

CAVE CRS File Naming Convention & FTP Path
(For Aqua data replace "AQUA" for "TERRA" in the following paths)
CERES data colocated with DOE Atmospheric Radiation Measurement (ARM) Program
File Prefix Surface SiteAnonymous FTP path
arm_C01_ ARM/SGP Central Facilitypublic/cave/CRS/TERRA/ARM
arm_E01_ Larned, KApublic/cave/CRS/TERRA/ARM
arm_E02_ Hillsboro, KA, Boundary Facility B01public/cave/CRS/TERRA/ARM
arm_E03_ LeRoy, KApublic/cave/CRS/TERRA/ARM
arm_E04_ Plevna, KApublic/cave/CRS/TERRA/ARM
arm_E05_ Halstead, KApublic/cave/CRS/TERRA/ARM
arm_E06_ Towanda, KApublic/cave/CRS/TERRA/ARM
arm_E07_ Elk Falls, KApublic/cave/CRS/TERRA/ARM
arm_E08_ Coldwater, KApublic/cave/CRS/TERRA/ARM
arm_E09_ Ashton, KApublic/cave/CRS/TERRA/ARM
arm_E10_ Tyro, KApublic/cave/CRS/TERRA/ARM
arm_E11_ Byron, OKpublic/cave/CRS/TERRA/ARM
arm_E12_ Pawhuska, OKpublic/cave/CRS/TERRA/ARM
arm_E13_ Lamont, OKpublic/cave/CRS/TERRA/ARM
arm_E15_ Ringwood, OKpublic/cave/CRS/TERRA/ARM
arm_E16_ Vici, OK, Boundary Facility B04public/cave/CRS/TERRA/ARM
arm_E18_ Morris, OKpublic/cave/CRS/TERRA/ARM
arm_E20_ Meeker, OKpublic/cave/CRS/TERRA/ARM
arm_E22_ Cordell, OKpublic/cave/CRS/TERRA/ARM
arm_E24_ Cyril, OKpublic/cave/CRS/TERRA/ARM
arm_MAN_ Tropical West Pacific, Manus Islandpublic/cave/CRS/TERRA/ARM
arm_NAU_ Tropical West Pacific, Nauru Islandpublic/cave/CRS/TERRA/ARM
CERES data colocated with WCRP Baseline Surface Radiation Network (BSRN) Program
File PrefixSurface SiteAnonymous FTP path
bsrn_ASP_ Alice Springs, Australiapublic/cave/CRS/TERRA/BSRN
bsrn_DAA_ De Aar, South Africapublic/cave/CRS/TERRA/BSRN
bsrn_FLO_ Florianopolis, Brazilpublic/cave/CRS/TERRA/BSRN
bsrn_GVN_ Georg von Neumayer, Antarcticapublic/cave/CRS/TERRA/BSRN
bsrn_LAU_ Lauder, New Zealandpublic/cave/CRS/TERRA/BSRN
bsrn_LIN_ Lindenberg, Germanypublic/cave/CRS/TERRA/BSRN
bsrn_NYA_ Ny Alesund, Norwaypublic/cave/CRS/TERRA/BSRN
bsrn_PAY_ Payerne, Switzerlandpublic/cave/CRS/TERRA/BSRN
bsrn_SBO_ Sede Boqer, Israelpublic/cave/CRS/TERRA/BSRN
bsrn_SSV_ Saudi Solar Villagepublic/cave/CRS/TERRA/BSRN
bsrn_SYO_ Syowa, Antarcticapublic/cave/CRS/TERRA/BSRN
bsrn_TAM_ Tamanrasset, Algeriapublic/cave/CRS/TERRA/BSRN
bsrn_TAT_ Tateno, Japanpublic/cave/CRS/TERRA/BSRN
CERES data colocated with NOAA Global Monitoring Division (GMD formerly CMDL) Program
File PrefixSurface SiteAnonymous FTP path
cmdl_BAR_ Barrow, AKpublic/cave/CRS/TERRA/CMDL
cmdl_BER_ Bermudapublic/cave/CRS/TERRA/CMDL
cmdl_BOU_ Boulder, CO (Boulder Tower)public/cave/CRS/TERRA/CMDL
cmdl_KWA_ Kwajalein Islandpublic/cave/CRS/TERRA/CMDL
cmdl_MLO_ Mauna Loa, HIpublic/cave/CRS/TERRA/CMDL
cmdl_SAM_ Samoapublic/cave/CRS/TERRA/CMDL
cmdl_SPL_ South Pole, Antarcticapublic/cave/CRS/TERRA/CMDL
CERES data colocated with SURFace Radiation (SURFRAD) Program
File PrefixSurface SiteAnonymous FTP path
surfrad_BON_ Bondville, ILpublic/cave/CRS/TERRA/SURFRAD
surfrad_DRA_ Desert Rock, NVpublic/cave/CRS/TERRA/SURFRAD
surfrad_FPK_ Fort Peck, MTpublic/cave/CRS/TERRA/SURFRAD
surfrad_GWN_ Goodwin Creek, MSpublic/cave/CRS/TERRA/SURFRAD
surfrad_PSU_ Penn State, PApublic/cave/CRS/TERRA/SURFRAD
surfrad_TBL_ Boulder, CO (Table Mountain)public/cave/CRS/TERRA/SURFRAD
surfrad_SXF_ Sioux Falls, SDpublic/cave/CRS/TERRA/SURFRAD
CERES data colocated with Independent Stations
File Prefix Surface SiteAnonymous FTP path
indoex_KAS_ Kaashidhoo Island, Indian Ocean Experiment (INDOEX)public/cave/CRS/TERRA/INDPND
larc_COV_ Chesapeake Lighthouse, Virginia Beach, VA (COVE)public/cave/CRS/TERRA/INDPND
unva_VAS_ Valencia Anchor Station, Valencia, Spainpublic/cave/CRS/TERRA/INDPND
whoi_PCN_ Woods Hole PACS Buoy North(10N, -125W)public/cave/CRS/TERRA/INDPND
whoi_PCS_ Woods Hole PACS Buoy South(-3S, -125W)public/cave/CRS/TERRA/INDPND
whoi_NT1_ Woods Hole NTAS I Buoypublic/cave/CRS/TERRA/INDPND
whoi_NT2_ Woods Hole NTAS II public/cave/CRS/TERRA/INDPND
whoi_ST1_ Woods Hole Stratus I Buoypublic/cave/CRS/TERRA/INDPND
whoi_ST2_ Woods Hole Stratus II Buoypublic/cave/CRS/TERRA/INDPND
whoi_ST3_ Woods Hole Stratus III Buoypublic/cave/CRS/TERRA/INDPND

Responsible NASA Official: Dr. Thomas Charlock
Data/Web Questions:David Rutan
Last Updated: 2008/05/02

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