Statistical Analysis On Sea Surface Anomaly And Mesoscale Eddies In The Kuroshio Extension And The South China Sea

The sea level anomaly (SLA) and mesoscale eddies during the period from 1993 through 2004 in the Kuroshio extension region(120oE-170oE, 25oN-45oN) and South China Sea(105oE-121oE, 0oN-25oN) are analyzed using altimetry data from CNES detected by TP/Jason-1 and ERS/ENVISAT. Based on SSHa detected by T/P and SST detected by AVHRR, correlation analysis between Nino3 index and SLA (or SSTa) in both areas is completed, to find how much El Ni?o event affects these two areas. Based on the data of SLA, mesoscale eddies are investigated, and the characteristics of eddy distribution and moving are analyzed statistically.It is found that the mean sea level anomaly of Kuroshio extension region and South China Sea in the 12-year period has a linear raise with a rate of 8.89mm/a and 5.34mm/a, respectively, and both areas have the most significant periods of 1 year,0.5 year and 6 years with low SLA in the first half year and high SLA in the second half year.The correlation between the low-frequency components of SLA/SSTa in the Kuroshio extension region and Nino3 index is high; the maximal correlation coefficient is -0.62/-0.63 with a lag of Nino3 index behind others for 11 months. In South China Sea, when Nino3 index is 2 months ahead of SLA, the correlation coefficient is -0.6251. When Nino3 index is 6 months ahead of SSTa, the correlation coefficient is 0.8120. These indicate that SLA/SSTa in both regions is closely related with the El Ni?o event.In the Kuroshio extension region, all of the mesoscale eddies move from east to west with a life time of about 1 year, and their longitudinal speed in about 10 degrees/year. Clockwise eddies and anti-clockwise eddies appear by turns in 32oN-36oN; In South China Sea, the eddies move irregularly. In the area near 15oN, some eddies move westward and the others move eastward. In the east of 113oE on 20oN, most eddies move westward, standing half a year and occupying 7 longitudinal degrees.Clockwise eddies and anti-clockwise eddies occupy almost the same area in both regions, which a fluctuation of one year period. However, the area occupied by these eddies reaches a...