华南前汛期起止日期的确定及降水年际变化特征分析

利用国家气候中心提供的华南地区74测站1957—2001年的逐日降水资料和NCEP/NCAR再分析资料，对华南前汛期雨季开始期与结束期的定义标准作了改进；研究了华南前汛期降水雨量、雨日的年际变化特征以及变化趋势的空间分布特征；用小波分析法分析华南前汛期降水的周期分布特征。分析结果发现：45年来前汛期开始期总体上呈现偏早趋势，而结束期具有偏晚的趋势，两者的年际变化十分显著；45年来华南全区总雨量、雨日呈正趋势变化，且两者的空间分布特征非常相似。华南前汛期内雨量、雨日总体上呈现增长趋势并且具有明显的年际变化特征，存在准2年、3～5年、6～8年的振荡周期。

ANALYSIS OF THE DEFINITION OF THE ONSET AND ENDING DATES OF THE ANNUALLY FIRST RAINY SEASON IN SOUTH CHINA AND ITS INTERANNUAL VARIATION CHARACTERISTICS

Based on the daily precipitation data of 74 observational stations in South China from 1957 to 2001 and NCEP/NCAR reanalysis data, the definitions of the onset and ending dates for the annually first rainy season in South China are studied. According to the result, the interannual variations and spatial patterns of the changing trend of rainfall and rainy days during the time are also investigated on the basis of the wavelet and trend coefficient analysis. The conclusions are as follows. The onset date has ...