The Characteristic And Mechanism Of Climate Changes During The Last 50 Years In Liaoning Province

In this paper, climatic changes of precipitation and air temperature, factors affecting summer rain fall and characteristics of high temperature hazards in Liaoning Province were studied based on climate data including precipitation and air temperature data of 39 observational stations in Liaoning province between 1961 and 2004, together with those of Shenyang, Fuxin, Dandong between 1951 and 2004, and 2°x2°sea surface temperature data, 5°x5°500hPa height data, and 5 parameters of subtropical high provided by China Meteorological Center. Tendency analysis, vector EOF expansion, correlation analysis were carried out in this study. The statistical results show that:1. both yearly and quarterly precipitation in Liaoning Province decreased slightly.2. the pattern of yearly and seasonal precipitation in Liaoning province can be divided into three regions, which are mainly in east-west direction.3. The main factors affecting summer precipitation in Liaoning province is the inner remote correlations between the summer atmospheric circulation and that of winter of the last year. The latitude of west pacific subtropical high and the longitude of its west point have critical influence on drought and flood interchanges. The development and mature phase of ENSO circulation tends to lead to less summer precipitation in Liaoning Province, and weak phase of ENSO leads to more summer precipitation. During La Nina years, if sunspot reach its high, Liaoning province has less summer precipitation and drought hazard, and there is more precipitation and flood hazard as sunspot reaches its low and the latitude of subtropical is much higher.4.The climatic tendency of air temperature of Liaoning province is that both yearly and seasonal average air temperature show slight increase, especially for winter air temperature, while spring, summer, autumn air temperature increase only a little.5.High temperature hazards mainly exist in West Liaoning, the east-west high in mid-latitude is the main weather pattern during these events.