Observational Facts Of Spring And Summer Land Surface Thermal Anomalies Over The Eurasian Continent And Its Relationship With Summer Rainfall In Eastem China

By using the ERA-40reanalysis, CRU-TS3.0dataset, and datasets of observation, the characteristic of Eurasian land surface thermal anomalies in spring and summer, and its relationship with summer rainfall in eastern China have been investigated. The results show that:(1)The large-scale characteristics of Eurasian land surface air temperature and shallow soil temperature are basically the same, but there are some differences in the north and southwest of Eurasia. Land surface thermal condition of northern Eurasia in spring and summer showing a warming trend in the last43years, the north of Eurasia is warmer than the south, and which is also warmer in spring than summer; however, the south of Eurasia showing a cooling trend. The first mode of Empirical Orthogonal Function decomposition of spring land surface thermal anomalies performance characteristics of reversal change between northern and southern Eurasian, which summer performance characteristics of reversal change between the southwest and other regions of Eurasian, time coefficient of both of them show shifts in the late80s of the last century. Observation data analysis also confirmed that land surface temperature and shallow soils temperature in China having a substantially uniform temperature change characteristics.(2) The relationship between the first mode of summer rainfall in eastern China and summer land surface thermal anomalies of Eurasia shows that, when summer land surface thermal anomaly of north India and the middle-east of china is positive, there is less precipitation in the Yangtze-Huaihe River Basin, while more precipitation in the southeast and northeast of China; vice versa. The relationship between the second mode of summer rainfall in eastern China and summer land surface thermal anomalies of Eurasia shows that, when summer land surface thermal anomaly of east and west of Lake Baikal is positive, while which is negative in northeastern China, then there is less precipitation in southeastern China and middle of Inner Mongolia, while more precipitation in the rest area of eastern China; vice versa.(3) When land surface thermal anomaly in the middle of mid-latitudes of Eurasia in May is negative, while land surface thermal anomaly in northwestern India in May is positive, then the pressure over middle and west of mid-latitudes of Eurasia is abnormally low in summer, while the pressure over the rest of Eurasia is abnormally high in summer, and there is abnormal southward wind in most parts of eastern China; Yangtze-Huaihe River Basin with less water vapor, and the upward movement is weak, while the rest of estern China with more water vapor, and upward movement is strong; Therefore, there is less precipitation in Yangtze-Huaihe River Basin, while more precipitation in the rest of estern China; vice versa. When land surface thermal anomaly in middle of high latitudes of Eurasia in May is negative, while land surface thermal anomaly in north of Indochina in May is positive, then the pressure over estern mid-latitudes of Eurasia is abnormally low in summer, while the pressure over southern Eurasia is abnormally high in summer, and there is abnormal southward wind in most parts of eastern China; southeastern China and eastern part of northwestern China with less water vapor, and the upward movement is weak, while the rest of estern China with more water vapor, and upward movement is strong; Therefore, there is less precipitation in southeastern China and eastern part of northwestern China, while more precipitation in the rest of estern China; vice versa.