This document describes the data set for Sea Surface Temperature
(SST) observed by the Visible Infrared Scanner (VIRS) aboard the
Tropical Rainfall Measuring Mission (TRMM).The SST was retrieved
from TRMM/VIRS Level 1 (1B01) standard products.
VIRSSST (Ver. 1.0) was produced and supplied by the Earth Observation
Research Center, Japan Aerospace Exploration Agency.
2. Directories and files
1) Browse images (gif format)
You can get three-day running mean (daily) and monthly mean SST browse images from the following URL:
*NOTE; that the three-day running mean image is calculated from one-day mean data, and the date of the filename for daily image is defined as the middle day of the three-day average.
2) Data (binary)
You can get one-day mean and monthly mean data from the following anonymous FTP sites:
Item (1,1) stores the value centered at 0.0E and 38.0N
Item (2880,609) stores the value centered at 0.125W and 38.0S.
3) Resolution
Horizontal
0.125 deg (LON) x 0.125 deg (LAT)
Temporal
Daily and Monthly
4) Missing values
Missing: 254
Land: 255
5) Conversion
You can calculate the real SST [C] from COUNT using the following
relationship:
SST [C] = COUNT/10.0 + 10.0
*NOTE that SST values less than 10 [C] were defined as 10 [C].
4. Example program for F77
c
c TO READ VIRS DAILY MEAN SST
c
parameter (idim = 2880, jdim = 609)
parameter (imiss = 254, land = 255)
parameter (rmiss = -999.0, rland = -777.0)
real*4 xsst(idim,jdim)
character*1 csst(idim,jdim)
integer*2 isst
character c1(2)*1, c2*2
equivalence (c1,c2)
101 format (a2)
c OPEN DATA FILE
open(10,file='virs_1day.19990101', access='direct',
2 form='unformatted', status='old', recl=idim*jdim, err=99)
c READ COUNT DATA
read(10,rec=1) csst
c CONVERT COUNT TO SST
do 100 i = 1, idim
do 110 j = 1, jdim
c1(2) = csst(i,j)
read(c2,101) isst
if (isst.eq.imiss) then
c MISSING
xsst(i,j) = rmiss
else if (isst.eq.land) then
c LAND
xsst(i,j) = rland
else
xsst(i,j) = real(isst)/10.0 + 10.0
endif
110 continue
100 continue
c CLOSE
99 close(10)
c STOP
stop
end
5. Display using GrADS
The Data is written in GrADS "non float data" format.
The Grid Analysis and Display System (GrADS) is an interactive desktop tool, which is available on almost UNIX workstations, Apple Macintosh, and DOS or Linux based PCs. You can get free GrADS software via anonymous ftp.
You can easily display 'VIRSSST (Ver. 1.0)' using the GrADS descriptor file:
Example for SST
DSET virs_1day.19990101
TITLE VIRS SST
OPTIONS yrev
UNDEF 254
XDEF 2880 LINEAR 0. 0.125
YDEF 609 LINEAR -38. 0.125
ZDEF 1 LEVELS 1000
TDEF 1 LINEAR 1jan1999 1dy
VARS 1
t1 0 -1,40,1 sst=t1/10+10
ENDVARS
For more information about GrADS, please read the GrADS documentation located on the GrADS Home Page.
6. References
Kachi, M., Imaoka, K., Murakami, H., Nakajima, T. Y., and Shibata, A.
(1999): Preliminary results of TRMM: Part II SST retrieved from TMI
10 GHz and its expected uses. Submitted to Marine Technology
Society Journal.
7. Notice
1) If you want to use VIRSSST browse images in publications, please
contact the EORC TRMM Office (
).
2) If you use VIRSSST data in publications, please include the following
credits:
"VIRSSST (Ver. 1.0)' was produced and supplied by the Earth
Observation Research Center, Japan Aerospace Exploration
Agency."
Also, we would appreciate receiving a preprint and/or reprint of those publications
utilizing VIRSSST data for inclusion in the TRMM bibliography. These
publications should be sent to:
The EORC TRMM Office
Earth Observation Research Center
Japan Aerospace Exploration Agency
22nd Floor Office Tower X, Harumi Triton Square,
1-8-10, Harumi, Chuo-ku, Tokyo 104-6023, JAPAN
FAX: +81-3-6221-9192
3) Please contact us for any comments, problems or questions at e-mail
address:
).