A Research On Bohai Sea Ice Retrieval Algorithm And Its Relationship With The North Pacific Sea Surface Temperature

In this paper, sea ice concentration(SIC) retrieval algorithm of Bohai sea isresearched and modified SIC retrieval algorithm is put forward based on the Opticalremote sensing data of NOAA/AVHRR（Advanced Very High Resolution Radiometer）;then we extract the interannual time series of Bohai sea ice parameters based on whichthe relationship between the earlier stage of the north Pacific sea surfacetemperature(SST) and Bohai sea ice changes is analyzed.To achieve more accurate SIC retrieval parameter in Bohai Sea using AVHRR data,spectral characteristics of different types of sea ice are obtained and analyzed by fieldmeasurement in Liaodong Bay using ASD spectrometer. Appropriate threshold isdetermined based on this and SIC is calculated using AVHRR retrieval algorithm. Inthis paper, retrieved SIC using LandSat5-TM data is used to compare and validate withAVHRR SIC of different combinational algorithms, meanwhile, muti-band retrievalalgorithm based on linear spectral mixture model (LSMM) is used for conducting aseries of band test algorithms. The result of error quantitative analysis indicates thatthe1245joint-band algorithm based on the LSMM model has the minimumerrors(ME,MAE,RMSE). On the basis of analyzing the spectrum distributioncharacteristics of the sea ice and sea water, a bilinear interpolation algorithm forretrieving Bohai sea ice concentration is proposed, this algorithm is based on theidentification criterion of Bohai sea ice and sea water. We compare the new SIC withLandSat data and analyze the errors; the result shows that the bilinear algorithm stillneeds further improvement.We establish Bohai sea ice time series of annual maximum extent and area usingmulti-band algorithm, which is used to supplement the original time series, and thenwe analyze the correlation between the previous SST change of north Pacific and Bohai sea ice. The result indicates that there is a significant correlation between theSST of August the year before in the north Pacific and the Bohai sea ice later year.The positive correlation area is located in west wind drift region, and the negativecorrelation area is located in the middle-east equator Pacific and the Kuroshio region.We analyze the correlation between the January500hpa geopotential height fieldwhich has great influence on Bohai sea ice and the early August SST, also the sameperiod SST in the west wind drift region and the middle-east equator Pacific. At thesame time, we analyze the self-correlation change of SST in the related sea areas anddiscussed the SST rhythm process in the related area of the west wind drift region.The result indicates that there are spatial and temporal disparities for the rhythmprocess in the west wind drift region; and the winter SST of Jan and Feb next yearmay be influenced by the SST of Jun to Sep early year through rhythm process, whichcould influence the Bohai sea ice.