中国极端降水事件时空特征及其对夏季温度响应

基于中国1951-2014年728个气象站点日降水数据,利用POT抽样、变异点分析、趋势分析、分段回归等方法全面分析中国极端降水事件（量级、频率与发生时间）非平稳性特征及其对夏季温度响应。研究结果发现中国极端降水量级有明显变异特征,但无显著趋势变化,中国极端降水频率则相反。并且中国极端降水次数在全国大部分区域有显著增加趋势。另外,研究还表明变异点对中国极端降水量级和频率趋势特征有明显的改变,对极端降水发生时间趋势特征改变较弱;中国极端降水发生时间在中南部呈显著上升趋势,其他区域趋势性不显著。中国大部分区域夏季温度呈上升或显著上升趋势,且变异特征显著。在转折点前,中国大部分区域如西部干旱区东南部、东部干旱区西南部、华北区、华中区和西南区北部夏季温度呈下降或显著下降趋势;在转折点后,上述区域夏季温度转为上升或显著上升趋势。

Spatiotemporal patterns of extreme precipitation with their responses to summer temperature

Daily precipitation and temperature data at 728 stations covering a period of 1951 to 2014 across China were analyzed to investigate extreme precipitation regimes in terms of spatiotemporal patterns, precipitation magnitude, precipitation frequency, occurrence timing, non-stationarity of extreme precipitation regimes and also their responses to summer temperature changes. The methods adopted in this study are Peak over Threshold (POT) sampling technique, change point analysis, trend analysis and piecewise regression method. Results of this study indicated that magnitude of extreme precipitation events was subject to evident alterations but free of significant trends. However, occurrence rates of extreme precipitation were subject to adverse changing properties when compared to changes in magnitude of extreme precipitation. The entire China was dominated by apparent increase of occurrence rates of extreme precipitation. Besides, change points within magnitude and occurrence rates of extreme precipitation tended to modify the changing tendency therein. However, occurrence timing of extreme precipitation events seemed to be free of impacts from change points. In most regions of China, occurrence time of extreme precipitation events was delayed and no changes in occurrence time of extreme precipitation could be observed in other regions of China.