Research On The Relationship Between The Changes Of Ozone In East Asia And The Precipitation In Yunnan

In this paper, monthly precipitation data of122stations of Yunnan in1979-2012and the reanalysis data in1979-2012provided by the European Information Center are used to analyze the changing characteristics of the precipitation of Yunnan and the changing characteristics of the ozone in East Asia and to analyze the relationship between the ozone abnormal variations in East Asia and the precipitation of Yunnan area and at the same time changes of SAH(South Asia High), which affect the precipitation of Yunnan. The following conclusions has been drawn:In the past decade, the precipitation of Yunnan was decreasing as a whole, especially in summer and autumn period which accounted for a large majority of annual precipitation, especially in the eastern and southern of Yunnan.The mainly characteristics of regional variation of total ozone is that the mean and standard deviation are large in high latitudes,and decrease in the summer and autumn, but increasing weakly around the Tibetan Plateau from June to October. The large mean of ozone concentration is range form1to100hPa, especially in10hPa, but100hPa is the biggest change level compare with the low-level region.The SVD analysis of the ozone in East Asia and the precipitation of Yunnan shows that the best correlation level of ozone is from100hPa to200hPa at the same period or one month in advance of precipitation in Yunnan, especially100hPa ozone in the same period, better correlation month are2,3,5,7and8, the critical area of ozone is northeast corner of Tibetan Plateau:95°E-115°E,38°N-48°N and the southeast corner:90°E-110°E,12°N-22°N.Compare the past few decades average monthly change of the total ozone and SAH’s shows that their distribution in the opposite positional relationship, where the ozone weaker but SAH is stronger, which is more obvious manifestation in East Asia, and their center almost at the same place. There are obvious differences of SAH between positive and negative anomalies years of ozone. SAH is weaker in the years of ozone positive anomalies, and Yunnan is located outside the center of high pressure, which is easy to produce precipitation due to the high pressure convection beyond the center. In contrast, SAH is stronger in the years of ozone negative anomalies, and Yunnan is in the control the center of high pressure, which is not easy to rain. There are also obvious differences for SAH and ozone between June to September. The beginning and perish time of the positive changes of SAH is about two weeks followed the positive changes of ozone changed, beginning and disappeared.The corresponding changes of SAH followed with the changes of the ozone in East Asia will affect the precipitation in Yunnan. So the changes of SAH can be roughly considered as the reason of the perfect correlation of the ozone in East Asia and the precipitation in Yunnan.