Real-time Hourly Sea Surface Temperature Retrieval Using Mtsat-1R Data

The sea surface temperature (SST) is one of the most important parameters in studies of atmosphere and ocean. The diurnal SST cycle becomes a hotspot in remote sensing, oceanic and climate research. Various infrared and microwave radiometers onboard geostationary satellite can measure SST over the fixed region continually. The study covers the area115°E～140°E,20°N～45°N,including Bohai sea, yellow sea, east China sea, the Japan sea and the western Pacific, in2008. In this area, the average depth of Bohai sea and yellow sea is less than50meters while the average depth of the western Pacific is more than2000meters.The Koroshio Current and the Oyashio Current cross the area. SST is extremely complex in this area.A new algorithm utilizing Multi-functional Transport Satellite-1R(MTSAT-1R) data has been developed for SST retrieval and interpolation SST. Cloud detection algorithms are combined with spatial coherence method, temporal coherence method, spatial-temporal coherence method and other threshold tests. The retrieved SSTs are calculated utilizing the Non-Linear SST (NLSST). Cressman analysis is used to interpolate the missing data and diurnal variation is considered. Verifying with drifting buoy observations, It shows that root mean square(RMS) error of cloud free pixels is0.76K, bias is-0.04K, the mean absolute errors0.60K; More than95%missing data can be filled, RMS error is0.81K, bias is-0.18K, mean absolute errors0.72K. The relationship between SST accuracy and several parameters are discussed. And cloud detection and bulk-skin effect have important effect on accuracy of SST algorithm. Compared with NGSST (New Generation Sea Surface Temperature)-O(Optimal interpolation),AMSR-E(The Advanced Microwave Scanning Radiometer-Earth Observing System)_TMI (Tropical Rainfall Measuring Mission Microwave Imager),MW (Microwave Imager)_IR (Infrared Scanner) SSTs,MTSAT-1R interpolation SSTs are better than NGSST-O SSTs.The study covers January to December,2008, over the area115°E～140°E,20°N～45°N. The study using the MTSAT SSTs and AMSR-E(The Advanced Microwave Scanning Radiometer-Earth Observing System) ascending and descending SSTs shows diurnal warming events occur more often in the area20°N-25°N and north of35°N. It is also shows that the diurnal warming events are more frequent in shallow waters than deep waters and the seasonal variation of diurnal warming is obvious. Significant diurnal warming events are observed over the studied area and SST differences of several events are over6K.The peak of SST diurnal cycle usually occurs on15or16local solar time, and bottom occurs on3local solar time. Similar result shows in diurnal warming events using interpolation SST.