Decadal Variations In Thermal State Of North Pacific Subsurface And Its Relation To Summer Precipitation And Temperature In East China

Based on the sea subsurface temperature (SUBT) and thermal capacity data in the North Pacific offered by JED AC, the precipitations and temperatures from 160 stations in China, and NCEP/NCAR reanalyses, we analyze characteristics of the upper-ocean thermal state of the North Pacific in winter and summer, the decadal climate characteristic in East China, then discuss the influence of the winter thermal capacity of the North Pacific to the summer precipitation and temperature in East China by SVD and the possible mechanism. Results show that:According to its characteristic, the winter SUBT in the North Pacific can be classified to be two types, both of which have obvious decadal feature. And SUBT change in western Pacific lag 5a behind that in the central part. Both of them have the periods of 8-9a and above 20a.The big-value area of decal variations is at the Kuroshio extension, which is strengthened from east to west. The anomaly of the winter thermal capacity in the North Pacific is similar to the 240m SUBT therein. The periods before 1967 and 1980-1988 are defined as the cool state of the North Pacific, with 1968-78 and after 1989 as the warm state. The characteristic of upper-ocean in summer is similar to the winter, but is more complex.The anomaly of the winter thermal capacity in the North Pacific has fairly good coupling relationship with the summer precipitation and temperature anomaly in East China. When the thermal capacity is higher in the north and the southeast of theNorth Pacific, the precipitation is more than mean in the South and North China while the temperature is lower than mean in south China;when the thermal capacity is higher in the Kuroshio extension as well as east of the North Pacific and lower in the west coast of North America, the precipitation is less in the Changjiang River valley and northeast China, while the temperature is lower in northeast and North China. Both of the coupling relationships of precipitation and temperature with the thermal capacity have considerable decadal characteristic. The correlation between winter thermal capacity in the North Pacific and summer climate anomaly in East China is most significant in the periods of la to 5a, in which the relation with precipitation is better than temperature.The North Pacific and the Tropic Pacific affects the climate of China indirectly by means of influencing the atmosphere circulation. Around the 1970's, the atmosphere circulation and the North Pacific presented the climate abrupt, which affects the atmosphere circulation and climate of East Asian, then leading East China precipitation to change remarkably.