影响中国及关键经济区热带气旋降水的气候趋势及极端性特征

本文利用中国气象局上海台风研究所整编的《热带气旋年鉴》(1951~2010年)最佳路径资料,分析影响我国和关键经济区热带气旋(TC)降水量、降水强度以及不同等级降水TC频数的气候变化趋势,研究结果表明,影响全国的TC总降水量的年际变化幅度大,年际差异显著。长江三角洲、珠江三角洲地区影响TC过程雨量年极值自1970年代开始缓慢上升,表明近年来TC引起的极端性降水存在增加的可能。全国范围内自1970年代开始,过程雨量大于250 mm的TC频数也在增加,但长江三角洲、珠江三角洲地区发生极端性降水的TC频数并没有明显的增长。TC造成的24小时降水极值的气候变化趋势不明显,但是1980年代全国范围内的24小时降水极值存在跃变。长江三角洲、珠江三角洲地区日降水极值超过250 mm的TC频数自1980年代开始有缓慢增加趋势。全国范围、长江三角洲及珠江三角洲内TC小时降雨量年极值呈现振荡的周期变化,而在年代际上没有明显的变化趋势。

Climatic Trends and Extremes of Tropical Cyclone Precipitation Affecting China and Its Key Economic Zones

In this study, 1951-2010 Tropical Cyclone (TC) Yearbook data from the Shanghai Typhoon Institute/China Meteorological Administration were used to investigate the evolution of precipitation characteristics of TCs that affect China and key economic zones, including the total precipitation and precipitation intensity, as well as the frequency of TCs of different precipitation grades. The results show that interannual variations in the total precipitation amount of TCs affecting China have been significant over the past 60 years. The annual maximum precipitation of TCs affecting the Yangtze River Delta and the Pearl River Delta have slightly increased since the 1970s, which means that the maximum precipitation due to TCs has possibly increased in recent years. Since the 1970s, the frequency of TCs in China with precipitation of more than 250 mm has increased, while the frequency of TCs affecting both deltas has not. The climate tendency of maximum precipitation in 24 h due to TCs is insignificant, but jumped during the 1980s. The frequencies of TCs with daily maximum precipitation of more than 250 mm affecting the Yangtze River Delta and the Pearl River Delta have slowly increased since the 1980s. The frequencies of TCs with hourly maximum precipitation affecting China and both deltas show periodic variation, but no significant decadal change.