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CAVE: Surface Observations

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Surface flux, Aerosol and Meteorology (SAM) files contain available surface
observed variables at over 60 locations around the globe.
The following table contains links to details explaning the files.

Link Description Example
Summary Summary of Surface Flux/Aerosol/Meteorology files. ----------
Site List A complete list of available surface sites. ----------
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:
On-Line Plots Summary tables of variables in each file and
on-line plots.
Example Table
Example Plot
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
IDL Code
SAM Statistic Files SAM data are averaged to 15 minutes.
Standard deviations and 'N' kept in separate files.
----------
Referencing Data Please reference data used appropriately. ----------
     
Access ftp
data base
Access ftp data base via the web from this link.  

Summary

CAVE surface observations consist of a host of radiometric, meteorological, and aerosol observations taken at a number of sites around the globe.  A number of organizations and people have generously made their data available for dissemination through this web site.  That data, generally arrives at 1 minute temporal resolution and for our purposes is averaged to 15 minute means. The data is rewritten as binary files, each file contains a header and all available data for a single site for a single month. These are then released via anonymous ftp along with programs to read the files. See the links above for lists of files at surface sites and an on-line plotting tool that prints summary tables of all variables available at a given site.

Surface Flux Aerosol & Meteorology (SAM) File Format

The SAM 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.

sam_format sam_variables
Figure 1. Graphic showing Surface Aerosol Meteorology (SAM)
file structure.
Figure 2. List of commonaly available data in SAM files.

Figure 2 lists the first 22 variables in every SAM file (identical in each SAM whether the surface site has recorded the data or not.) Most sites do not record all these varialbes. Some observe more. If a site has more data of interest, UV data at SURFRAD sites for instance, these data are include as "Extra" variables in records beyond #22. The number of extra variables in a file is recorded in the file header. For quickly determining available data at a site go to the SAM PLOT page where a summary table for all sites in the data base can be quickly accessed.

File Naming Conventions and Directory Paths at FTP Site

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

Surface Flux Aerosol & Meteorology (SAM) Statistics Files

Most data coming into our data base arrive as 60 second averages of 1Hz observations. For our purposes we average these data to 15 minutes (minutes 0 throug 14, 15 through 29, etc...) Often too, data might be missing. So, statistic files containing the standard deviation of the data over each 15 minute time period and the number of points that go into each 15 minute average are also maintained and made available for interested parties. The naming convention is the same execpt instead of "avg" they have "sts" before the version number.

FileFile Nameftp directory path
15 minute average filesurfrad_FPK_200208.avg.v3.0public/CAVE/SAM/SURFRAD/
Companions statistics filesurfrad_FPK_200208.sts.v3.0public/CAVE/SAM/SURFRAD/stats/

These files are found in a subdirectory name "stats" inside each program directory where the 15 minute average files are found. A program to read them is available:

readstats.f90

The format of these files is nearly identical to the average file except that for each variable there are two records, the standard deviation and count.

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

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