基于REOF分析的江西主汛期降水趋势的区域特征

Regional Characteristics of Precipitation Trend in the Major Flood Season Based on REOF Analysis in Jiangxi

摘要: 采用旋转经验正交展开方法，对江西省主汛期(4~6月)降水进行分区，在此基础上运用线性趋势法、Mann-Kendall检验法与Morlet小波分析法，研究各分区主汛期降水的长期演变规律。结果表明：江西省主汛期降水量场可以划分为2个区域，即赣北与赣南，赣北主汛期降水无明显趋势；赣南主汛期降水存在减小的趋势，倾向率约为−17 mm/10 a，赣南主汛期降水在20世纪80年代末至今下降趋势显著，最近一次突变时间在1976年左右。周期分析表明，35 a为赣北主汛期降水系列第1主周期，赣北主汛期降水的中小周期分别为11 a，6 a和3 a；43 a为赣南主汛期降水系列第1主周期，赣南主汛期降水中小尺度对应17 a、25 a、6 a、4 a、10 a周期。

Abstract: This paper used REOF analysis method to classify the standardized rainfall anomaly field during major flood season (April to June) in Jiangxi, and then used linear trend method, Mann-Kendall test method and Morlet wavelet analysis method to analyze long-term trends of precipitation in each sub-district. Evidence reveals that, the standardized rainfall anomaly field in the major flood season in Jiangxi is classified into two districts, north Jiangxi and south Jiangxi. There is no obvious trend of precipitation in the major flood season in north Jiangxi; precipitation in the major flood season of south Jiangxi is decreasing with a tendency rate of 17 mm/10 a in the long run, an evident downtrend has been happening since the end of 1980s, the recent mutation is around 1976. The wavelet analysis suggests that, 35 a is the first main period of the major flood season precipitation series in northern Jiangxi, 11 a, 6 a and 3 a are its meso-micro scale periods. 43 a is the first main period of the major flood season precipitation series in south Jiangxi, and 17 a, 25 a, 6 a, 4 a and 10 a are its meso-micro scale periods.