ESTIMATION OF SEA-SURFACE TEMPERATURE VIA AVHRR OF NOAA-9 - COMPARISON WITH FIXED BUOY DATA

By using the match-up data sets of Advanced Very High Resolution Radiometer (AVHRR) brightness temperatures of NOAA-9 and buoy sea surface temperatures in Mutsu Bay in northern Japan, the accuracy of the five split-window functions derived from the regional data sets and the fourteen published SWFs were evaluated. The match-ups were carefully screened from the HRPT scenes of all seasons in 1985-1988. The temporal and the spatial coincidences are within 30 minutes and one pixel resolution, respectively. The regional SWFs had the RMSDs in the range of 0.55-0.75-degrees-C. The RMSDs of the published SWFs were in 0.56-2.31-degrees-C. Several published SWFs showed RMSDs of less than 0.8-degrees-C for all the five test data sets. Most published SWFs accompanied with larger RMSDs increased their values due to larger biases. The effectiveness of the split window method was fundamentally confirmed for the local SST estimation. The statistics of errors, however, delicately depended upon the coefficients of SWFs, which were determined by atmospheric profiles or match-up data set used in the derivation. For better SST estimation, the split window functions should be calibrated by a regional match-up data set of the investigation.