README file for Surface Aerosol & Meteorology (SAM) CAVE data files.

Summary:
--------

CAVE surface observations consist of a host of radiometric, meteorological, 
and aerosol observations taken at a number of sites around the globe.  Many 
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 using the http tool along with programs to read the files. See:

   http://www-cave.larc.nasa.gov/cave/pages/sam.html

for a complete description of the files; a complete lists of available 
months for each surface site;  an on-line plotting tool that prints summary 
tables of all variables available at a given site and plots desired variables.


File Format:
------------

Data are real, direct access, 8-bit binary, of record length 11904 bytes.
They are written using fortran 90 code on an Unix-SGI (i.e. Big-Endian)
Each file 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.

Basic Data Set:
---------------

Each file contains a basic list of 22 variables (not all of which 
are necessarily available.) 

Header

 Character (Len=64) :: Site_ID               !   64 bytes    64 
 Character (Len=4)  :: year                  !    4 bytes    68
 Character (Len=4)  :: mon                   !    4 bytes    72
 Real	 :: lat                              !    4 bytes    76
 Real	 :: lon                              !    4 bytes    80
 Real	 :: elev                             !    4 bytes    84
 Real	 :: extras                           !    4 bytes    88
 Character (Len=32), Dimension(50) :: label  ! 1600 bytes  1688
 Character (Len=10216) :: padding            !10216 bytes 11904 (=2976*4)

Data

( 1) = 'Cos(Sol Zen Ang)   (-----)
( 2) = 'LW Flux DN	   (W/m*m)
( 3) = 'LW Flux UP	   (W/m*m)
( 4) = 'SW Global DN	   (W/m*m)
( 5) = 'SW Global UP	   (W/m*m)
( 6) = 'SW Direct Normal   (W/m*m)
( 7) = 'SW Dif DN UnAdj    (W/m*m)
( 8) = 'Total SW Dn,Dir+Dif(W/m*m)
( 9) = 'Temp 10m	   (Deg C)
(10) = 'Sfc Pressure	   (   mb)
(11) = 'Sfc Wind Speed     (  m/s)
(12) = 'Sfc Wind Dir	   (+degN)
(13) = 'Sfc Rel Humidity   (	%)
(14) = 'Cloud Fract (SWFA) (  0-1)
(15) = 'Aer OD-1 nnnn nm   (-----)
(16) = 'Aer OD-2 nnnn nm   (-----)
(17) = 'Aer OD-3 nnnn nm   (-----)
(18) = 'Aer OD-4 nnnn nm   (-----)
(19) = 'Aer OD-5 nnnn nm   (-----)
(20) = 'Aer OD-6 nnnn nm   (-----)
(21) = 'Aer OD-7 nnnn nm   (-----)
(22) = 'Aer PW  	   (   cm)

Beyond this list files may contain extra data. The number of extra
variables (if any) is given in the header record by the variable
"extras"

For example all SURFRAD sites have UVB and PAR radiation along
with their basic suite of instrumentation.