EXERCISE IN DOWNSCALING ON SEA SURFACE TEMPERATURE ALONG CHINESE COAST

The present study examines the relationship between observed variations of regional hydrographic elements and concurrent large scale climatological parameters. The former were chosen as the monthly sea surface temperature along the Chinese coast; the latter were chosen as monthly mean sea level pressure and sea surface temperature for the period from 1960 to 1990, which are reasonably well simulated by present day climate models. The variations of the former, due to variations of the regional atmospheric forcing and of oceanic circulation, are not adequately simulated by a global climate model because of insufficient spatial resolution. A statistical “downscaling" strategy is applied to the former. To better understand their variation mechanism and study the relationship among the environmental parameters in a group, canonical correlation analysis with combined datasets was carried out. The results show that variations of hydrographic elements are heavily forced by the East Asian monsoon through monsoon wind and rainfall.

The present study examines the relationship between observed variations of regional hydrographic elements and concurrent large-scale climatological parameters. The former were chosen as the monthly sea surface temperature along the Chinese coast; the latter were chosen as monthly mean sea level pressure and sea surface temperature for the period from 1960 to 1990, which are reasonably well simulated by present day climate models. The variations of the former, due to variations of the regional atmospheric forcing and of oceanic circulation, are not adequately simulated by a global climate model because of insufficient spatial resolution. A statistical “downscaling” strategy is applied to the former. To better understand their variation mechanism and study the relationship among the environmental parameters in a group, canonical correlation analysis with combined datasets was carried out. The results show that variations of hydrographic elements are heavily forced by the East Asian monsoon through monsoon wind and rainfall. Key words downscaling - sea surface temperature - Chinese coast Contribution No. 3238 from the Institute of Oceanology, Chinese Academy of Sciences. Project 49476274 supported by NSFC and the Chinese Academy of Sciences President's fund (YJJZ No. 218), also supported by Key Lab. of Marine Environmental Sciences and Numerical Modelling of SOA.