Information for the use of the NMC SST analyzed fields The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST plus SST's simulated by sea-ice cover. Before the analysis is computed, the satellite data is adjusted for biases using the method described by Reynolds (1988) and Reynolds and Marsico (1993). A description of the analysis can be found in Reynolds and Smith (1993). Because this document has not yet been published, a preprint of the document is available by request. The bias correction improves the large scale accuracy of the OI. Examples of the effect of recent corrections is given by Reynolds (1993). The bias correction does add a small amount of noise in time. Most of the noise can be eliminated by using a 1/4-1/2-1/4 binomial filter in time. We STRONGLY recommend that this filter be applied to the data fields before they are used. An improved method of correcting the biases is being developed. For the more recent period, 1990-present, the in situ data were obtained from radio messages carried on the Global Telecommunication System. The satellite observations were obtained from operational data produced by the National Environmental Satellite, Data and Information Service (NESDIS). For this period the weeks were defined to be centered on Wednesday. This was done to agree with the definition used for ocean modeling. During the period 1985-1989, the in situ data were obtained from a preliminary version of the Comprehensive Ocean Atmosphere Data Set (COADS) for the 1980s. These data (see Slutz, et al., 1985) consist of logbook and radio reports. The satellite data were obtained from analyses of NESDIS data produced at the University of Miami's Rosenteil School of Marine and Atmospheric Sciences. These satellite analyses were produced for weeks centered on Sunday. Thus the OI weekly analyses for 1985-1989 also were centered on Sunday. We hope that this change in the definition of the week will not cause any problems. All files can be read with the following fortran program: PROGRAM RSST DIMENSION SST(360,180) INTEGER ISST(360,180) IWK=0 OPEN(10,FILE='filename') c Loop for each week 200 READ(10,6,END=100) IYRST,IMST,IDST,IYREND,IMEND,IDEND,NDAYS,INDEX 6 FORMAT(8I3) READ(10,8,END=100) ISST 8 FORMAT(20I4) DO 32 I=1,360 DO 31 J=1,180 SST(I,J) = 0.01*FLOAT(ISST(I,J)) 31 CONTINUE 32 CONTINUE IWK =IWK + 1 c Print date info and SST at one location for first 10 weeks IF (IWK.LE.10) PRINT 7,IWK, 1 IYRST,IMST,IDST,IYREND,IMEND,IDEND,SST(70,80) 7 FORMAT ('IWK =',I3,3X,'DATES =',3I3,' - ',3I3,3X, 1 'SST (110.5W,10.5S) =',F6.2) GO TO 200 c Print date info and SST at one location for last week 100 PRINT 7,IWK, 1 IYRST,IMST,IDST,IYREND,IMEND,IDEND,SST(70,80) STOP 1 END ! The first read gives the start date (year, month, day) and end date (year, month, day) of the analysis. The next variable is the number of days used in the analysis (the value is 7); the last variable is a version number (it may be ignored). The next read gets the ISST array. The values are degrees Celsius times 100. The first dimension (variable I) is longitude, the second dimension (variable J) is latitude. I = 1 is 179.5W; I = 2 is 178.5W; and so on to I = 360 which is 179.5E. J = 1 is 89.5S; J = 2 is 88.5S; and so on to J = 180 which is 89.5N. Values set to -1.80 degrees Celsius represent sea ice. REFERENCES Reynolds, R. W., 1988: A real-time global sea surface temperature analysis. J. Climate, 1, 75-86. Reynolds, R. W., 1993: Impact of Mount Pinatubo aerosols on satellite-derived Sea Surface Temperatures. J. Climate, 6, 768-774. Reynolds, R. W. and D. C. Marsico, 1993: An improved real-time global sea surface temperature analysis. J. Climate, 6, 768-774. Reynolds, R. W. and T. S. Smith, 1993: Improved global sea surface temperature analyses. J. Climate, accepted subject to revisions. Slutz, R. J., S. J. Lubker, J. D. Hiscox, S. D. Woodruff, R. L. Jenne, D. H. Joseph, P. M. Steuer, J. D. Elms, 1985: Comprehensive Ocean-Atmosphere Data Set: Release 1. NOAA Environmental Research Laboratory, Boulder, CO, 268 pp. Richard W. Reynolds (INTERNET: wd01rr@sgi11.wwb.noaa.gov) Diane C. Marsico (INTERNET: wd01dm@sgi26.wwb.noaa.gov Coupled Model Project W/NMCx3 National Meteorological Center World Weather Building, Room 807 5200 Auth Road Camp Springs, MD 20746 USA PHONE: (301) 763-8396 FAX: (301) 763-8125 UPDATED: 14 July 1993 NOTE : THIS DATA IS MEANT FOR RESEARCH USE ONLY AND NOT FOR COMERCIAL USE.