DATA SET:       234.0
TITLE:          ANTARCTIC MONTHLY ICE 1973-1990 FROM ROPELEWSKI, CAC
VOLUME:         69KB 
TYPES:          GRIDDED TIMESER SEANAL OCEAN
GRIDS:          ANTARCTIC POLAR 1X36
LEVELS:         SFC
VARIABLES:      ICE
PERIODS:        1973JAN-1990MAR
TIMES:          MOLY
SOURCES:        ROPELEWSKI CAC

  FORMAT -
      DIMENSION VAL(36)
      READ(1,'(36X,2I2)')IYR,IMO
      READ(1,'(9F8.2)')VAL
   WHERE THE 36 VALUES ARE FOR 10 DEGREE BOXES BEGINNING WITH 0 TO 10 E
   AND MOVE EASTWARD.


            Antarctic Sea-Ice Index Data from CAC (Jan. 1973-1990)
            --------- --- --- ----- ---- ---- ---  ---  ---- -- 

Monthly sea-ice area data is available for each 10 degrees of longitude
for Antarctica starting January 1973.  These data are based on weekly
charts prepared by ohe Naoy-NOAA Joint Ice Center, (but not all charts
are used).  Grid boxes 1 x 2.5 longitude were placed over an analyzed
chart.  A box is considered to have sea-ice if it is more than
half-filled with ice.  The concentration of sea-ice was not considered
except that concentrations of less than 1/8 (called "open water") were
not counted.  Therefore, large areas of open water are not included as
sea-ice (unlike some other studies).  Permanent shelf ice and areas of
the Antarctic continent were excluded.  It has not been possible to
digitize each weekly chart for this index.  The weekly chart dated
closest to the end of the month was used to designate the sea-ice cover
for that month (It is not in the middle of the month).


There are 36 numbers for each month (in units of 10**3 km**2).  The
first is sea-ice area for 0- 10E, then 10-20E, etc.  The user can
prepare indices for the whole of Antarctica or for the six sub areas as
defined in the reference. 

Ropelewski, Chester F., 1983:  Spatial and temporal variations in Antarctic
sea-ice (1973-82).   J. Clim. and Appl. Met. 22, pp 470-473.
                     -  ----  --- ----  ---