华东地区登陆台风降水变化的初步研究

Preliminary Study on Variations of Landfalling Tropical Cyclone Rainfall over East China

利用华东地区129站1954—2004年逐日降水量资料,用降水客观分离的方法及其改进方案对登陆该地区的台风降水(tropical cyclone precipitation;TCP)进行分离;再用方差分析、气候趋势系数和线性回归等方法,分析TCP的气候特征,并与总降水的相应特征比较。结果表明:华东地区登陆台风降水量空间分布不均匀,福建东南沿海地区最大,具有向西北方向递减的趋势,这种趋势与地形等因素有关;TCP的年际变化明显,9 a和15 a周期显著;TCP年代际变化表现为20世纪50年代最多,70年代前开始减少,比华北地区台风降水减少出现的时间提早10 a;TCP与总降水两者的时间演变特点差异较大。

The landfalling tropical cyclone precipitation （TCP） over East China was partitioned from the daily rainfall observations at 129 stations during 1954--2004 by the Objective Synoptic Analysis Technique and its advanced scheme. The climate characteristics of TCP were analyzed with variance analysis, trend coefficient and linear regression technique, followed by comparison with those of annal total rainfall in East China. Results show that the spatial distribution of TC rainfall is not uniform in East China with the highest rainfall occurring in southeast Fujian Province, and the decreasing feature of TCP from southeast to northwest is related with the terrain and other factors. The interannual oscillation of TCP volume is evident with marked 9-year and 15-year periods, and the inter-decadal variability of TCP is that the maximum occurred in the 1950s, and then decreased before the 1970s,which is 10 years earlier than the time in North China. The climate characteristic of total precipitation is greatly different from that of TCP. Thus it makes sense to extract TCP from total precipitation before making long-range precipitation prediction.