【摘要】 利用我国586个气象测站的逐日降水资料,在对每个站点极端降水过程阈值进行科学界定的基础上,揭示了近45年我国年和各季极端降水过程频数的线性变化趋势及其年际、年代际变化特征.结果表明:我国年和季节极端降水过程频数主要为趋势性变化,不同地区不同季节趋势性变化差异显著,极端降水量在降水总量的趋势变化中占主导地位;长江中下游、西北地区北部和西南地区西部年极端降水过程频数呈现趋势性增加,而我国华北等地区呈现趋势性减少,并且主要反映的是夏季的特征;年和季节极端降水过程频数具有明显不同的年际和年代际变化特征;我国各季极端降水过程时空变化异常型明显不同,但与极端日降水的时空变化是一致的.更多还原

【Abstract】 The daily precipitation data from 586 stations in China are used in this study. Based on the scientific definition of the thresholds of the annual and seasonal extreme precipitation processes for each station, the numbers of annual and seasonal extreme precipitation processes are calculated, and the linear trend, the annual and decadal variations of the number of annual and seasonal extreme precipitation processes in the recent 45 years are then analyzed. Results show that the spatio-temporal variations of the number of the extreme precipitation processes have significant linear trends; the trends of the number of the extreme precipitation processes vary significantly in different seasons and regions, and the extreme precipitation contributes a lot to the trend of the overall quantity of rainfall. Along the middle and lower reaches of the Yangtze River, in the northern part of Northwest China and the western part of Southwest China, the number of the extreme precipitation processes increase linearly; while in North China, there is an opposite trend. Such a trend distribution shows mainly the characteristics in summer. The number of the extreme precipitation processes of China in different seasons also shows significant variations on interannual and interdecadal scales. For each season, the anomalous patterns of the extreme precipitation processes have distinctive difference, but they are similar to the extreme daily precipitation.更多还原