BASS Blended Analysis of sea Surface Salinity 
            Version 0.x

1.  Data File Name 

    BASS_V0.X_DLY_1DEG.lnx.RYYYY


2.  Contents

    analyses of 5-day mean SSS anomaly and estimated error (psu) on a 1 degree 
    latitude / longitude grid over the global ocean 

    Anomaly is defined relative to the monthly SSS climatology of Levitus (1994)  


3.  File structure 

    The data file is a direct access binary data file. 

    The data is arranged in the order of day of the year. 

    The data for each day (5-day mean) is composed of two global fields, the first for the 
    analyzed SSS anomaly (psu) and the second for the estimated error for the 
    SSS anomaly (psu). 

    Each globe field is an array of 360 elemets in east-west direction and 180 lines in 
    south and north direction. 

    The global array starts from the 1deg lat/lon grid box at the south-west corner centering 
    at (0.5deg E; 89.5deg S). 

    The global array goes first from west to east, so that the second element in the array is 
    the data at the grid box centering at (1.5deg E; 89.5deg S).    

    Once covering all 360 elements in the south-most line, the array continues into the second line, 
    so that the 361st element in the array is the data for the grid box centering at (0.5deg E, 88.5deg S)

    Each data is a 4-byte floadting number written in little endian byte order (the byte order 
    used by all linux based work station). YOU NEED TO SWAP THE BYTE ORDER TO BIG ENDIAN IF 
    YOU ARE WORKING WITH A SUPER COMPUTER.

    Missing code is -999.0.

    The size of the data file is therefore 

    4 byte (each number ) x 360 (elements in E-W direction) x 180 (lines in S-N direction) x  
    2 (fields, anomaly and error) x 365/366 (days in a year) 

    = 189216000/189734400 bytes   

4.  Sample fortran program to read the data file 

      program     :     teatread.lnx.f  
      objective   :     to test read the BASS salinity data 
c
      parameter  ( nx = 360, ny = 180, ndays = 365/366 ) 
c
      dimension  sss (nx,ny), err (nx,ny) 
c
c     1.  to open the data file 
c 
      open  (unit=10, 
     #       file='BASS_V0.X_DLY_1DEG.lnx.RYYYY', 
     #       access='direct', recl=nx*ny*4) 
c
c     2.  to read the data 
c 
      do 2001 kmm = 1, ndays
        kinp1 = (kmm-1)*2 + 1 
        kinp2 = kmm*2 
        read  (10,rec=kinp1)  sss 
        read  (10,rec=kinp2)  err 
        write  (6,*)  'finished reading data :', kmm, sss (180,90), err (180,90) 
 2001 continue 
c
c
      stop 
      end 

5.  Point of Contact 

    Pingping Xie 
    NOAA Climate Prediction Center 
    5830 University Research Court, #3003 
    College Park, MD 20740 

    E-Mail:  Pingping.Xie@noaa.gov 
    Tel:     301-683-3388