近47年云贵高原汛期强降水和极端降水变化特征

利用云贵高原159个常规气象站1961～2007年汛期（5～10月）逐日降水量，用百分位法定义站点强降水和极端降水阈值，对强降水和极端降水事件进行了分析研究。结果表明：云贵高原汛期强降水和极端降水阈值地理分布差异较大，与汛期降水量关系不大，而与站点海拔高度显著负相关；1961～2007年汛期降水量变化趋势不明显，但降水日数显著减少，降水有集中的趋势；强降水量和极端降水量具有与汛期降水量相似的年际波动特征，极端降水与汛期降水的相关高于强降水；以强降水量和极端降水量与汛期降水量的比重表征事件的强度，两者均呈显著增加的变化趋势，并在1990年代初期发生了显著增加的突变；强降水和极端降水与夏季季风强弱变化显著负相关。

CHANGE CHARACTERISTICS OF SEVERE RAINFALL AND EXTREMERAINFALL IN FLOOD SEASON OVER YUNNAN GUIZHOU PLATEAUIN RECENT 47 YEARS

Using the daily rainfall data of 159 stations during the flood season (from May to October) in the period of 1961～2007 in Yunnan Guizhou Plateau,the severe rainfall and the extreme rainfall thresholds of different stations was defined by percentile method,and the severe rainfall and the extreme rainfall events were analyzed.The results showed that in geographic distribution features,the thresholds of the severe rainfall and the extreme rainfall events in Yunnan Guizhou Plateau had biggish difference.The correlation of the thresholds with the total precipitation in flood season was not significant,but with the sea level elevation of stations was close negative.The variation trend of the total precipitation in flood season was not obvious in the period of 1961～2007,but the rainfall days displayed a significant decreasing trend,and the precipitation had a concentrating trend.The severe precipitation and the extreme precipitation had similar annual undulation features with the total precipitation in flood season,and the correlation of the extreme precipitation with the total precipitation in flood season was better than the severe precipitation.Using the ratio of the severe rainfall and the extreme rainfall to the total rainfall in flood season indicated the intensity of events.Both of them showed remarkable rising,and occurred a sudden rising change in the beginning of 1990s.There was an obvious anticorrelation between the severe rainfall,the extreme rainfall and the change of summer monsoon intensity.