Abstract:

ENSO is one of the most significant signal to the mutual coupling between the atmosphere and the sea.In this paper the response characteristics of the extreme rainfall over eastern China(the areas to the east of 100°E) in different seasons to the ENSO were studied by taking the use of the percentile method to define the extreme precipitation，and the possible reasons in the air properties were also analyzed by the use of moist potential vorticity(MPV) because of its own characteristics.The results showed that the threshold of the extreme rain reached the heavy rain standard in most areas in the summer since it was a rainy season itself and achieved only moderate rain in the winter.The frequency of the seasonal extreme precipitation showed its special distribution characteristics that in the spring the extreme rain mostly occured in the south area and in the summer the areas along the coast and in the southwest showed more extreme rain.While in the autumn it was the most area of the westsouth which had more extreme rain,and the northeast of the Neimeng province occured less in each season.When it came to the ENSO,it had another pattern.The extreme rainfall differed significantly over the east area of the Northern China in the warm and cold years，respectively the negatively anomaly filed and the positive anomaly field．In the spring and summer of the following year of Einino，it had nearly the same distribution that the north exsited more and the south exsited a complex distribution that there was a great value over the south area of the Yangtze River valley.In the autumn of the following year，constrasting to the spring and the summer，the big value shifted apparently and it was main over the northern region；and in the winter of the following year of Einino，it mainly had less．However，it nearly presented an adverse distribution pattern in the following year of Lanina.According to the study above we could conclude that in the summer of the following year,the extreme precipitation distribution differed from spatial distribution of the precipitation.In addition,the spring and summer of the following year of the cold year had a higher reliability,while in the autumn and winter it was the following year of the warm year which was more credible.The corresponding MPV could well reflect the atmospheric stability of the north area，especially over the Northern China,that is to say the MPV showed a positive anomaly field over the Northern China in the summer of the warm year and a negative anomaly field in the summer of the cold year.However,because of the many factors affecting the extreme precipitation,only taking the advantage of the changes of the atmospheric nature can not well be the fine basis of the extreme precipitation forcast in the lowlatitude region