Methodology to obtain accurate sea surface temperature from locally received NOAA-14 data in the Canary-Azores-Gibraltar area

A methodology to obtain the sea surface temperature (SST) in the Canary-Azo res-Gibraltar area has been developed. The final accuracy of the AVHRR-base d SST retrievals depends both on the accuracy of the measured radiance and the accuracy of the SST retrieval algorithm that converts the measured radi ance into sea surface temperature. The procedure made in this framework con sists of: (i) a radiance-based non-linearity correction methods (ii) an aut omatic procedure for the geometric correction, achieving accuracy to the or der of the pixel; (iii) an improved algorithm for cloud detection, based on the method of the multiband thresholds (iv) a new split-window function (S WF) to perform atmospheric correction in CANIGO area. This task has been ac complished by using the matchup data set of AVHRR brightness temperature (c hannel 4 and 5) and in situ SST data. The matchups were carefully screened from the HRPT scenes of all seasons in 1996-1998. The temporal and spatial coincidences are within 30 minutes and one pixel resolution, respectively. Coefficients of that algorithm are estimated from regression analysis using 60 co-located in situ and satellite measurements (matchups). Error analysi s has shown that SST can theoretically be retrieved to within 0.38 degreesC RMS.