Research On Tibetan Plateau Winter And Spring Atmospheric Heat Source Anomaly Influence The Early Summer Rainfall In Yunnan

Based on122stations early summer (may and June) precipitation data from1961to2013in Yunnan province and1961-2013NCEP/NCAR daily and mean monthly reanalysis data, the distribution and changes of atmospheric heat source in the Tibetan Plateau are analyzed. Using EOF method, the Tibetan plateau atmospheric heat source in winter and spring are analyzed, as well as the early summer rainfall in Yunnan; winter and spring atmospheric heat source anomaly of the Tibetan plateau and the relationship with the early summer rainfall in Yunnan are analyzed by using the methods of SVD and synthetic analysis, and preliminary discussion on the relationship between the soil humidity and atmospheric heat source in Tibetan plateau. The results show that:(1) The Tibetan plateau atmospheric heat source in winter is mainly the heat sink, western plateau in February turn from a heat sink into a heat source at first, and the eastern one month later. In spring, the Tibetan plateau region mainly control by heat source1. Winter and spring atmospheric heat source EOF the first modal in southwest to northeast and things on both sides of the phase change of oblique wave train type, coefficient of time sequence is given priority to decade variability.(2) Early summer precipitation in Yunnan province shows the south more north less distribution. May precipitation has a tendency to rise, June rain is falling. The spatial and temporal variations of May and June precipitations are not synchronous, and the years that picked out by the positive and negative anomalies are not the same.(3) Yunnan May precipitation and Tibetan plateau atmospheric heat source over the same period negatively correlated in the northwest and southeast, positively correlated in the middle, the best correlation regions of the Tibetan plateau in the middle and the west. Yunnan May precipitation and the early stage of the atmospheric heat source from northwest plateau to the east is ’+-+’ distribution, the consistency lasts for some time. Synthesis analysis is consistent with SVD the first modal distribution.(4) Yunnan June precipitation in positive and negative anomaly has little relationship with the winter plateau atmospheric heat source.In positive anomaly year, spring atmospheric heat source on the northwest Tibetan Plateau has one abnormal negative anomaly signal, but in negative anomaly year, the negative anomaly is in the central plateau, and positive anomaly in the east. (5) Winter and spring Tibetan plateau atmospheric heat source anomalies do have effects on Yunnan May precipitation, and they can be used as a predictor. But they have no significant effects on Yunnan precipitation in June.