基于REOF分析的广东前汛期降水趋势的区域特征

采用旋转经验正交展开(REOF)方法,对广东48站前汛期降水标准化距平场进行客观分区,在此基础上对各区区域平均前汛期降水的长期演变趋势进行了讨论。结果表明:广东省前汛期降水量场可以划分为4个区域,即粤东区、粤中区、粤西北区以及雷州半岛区。该4区前汛期降水量线性趋势不显著,年代际变化特征明显。进入21世纪以来,除雷州半岛区降水持续减少外,其余各区出现明显增加。而20世纪90年代以来粤东区和粤中区旱涝发生更为频繁。

Regional Characteristics of Precipitation Trend in Pre Flood Season Based on REOF Analysis in Guangdong

Based on the REOF analysis and the classification of the standardized rainfall anomaly field in the pre flood season in Guangdong,the long-term trends of the regionally-averaged rainfall are studied.Evidence reveals that,the precipitation field in the pre flood season can be clustered to 4 regions,East Guangdong,North Guangdong,Central Guangdong and Southwest Guangdong.The linear trend of the pre flood season precipitation in each region is not prominent,while the features of the inter-decadal change are obvious.From the beginning of the 21 century,the precipitation in pre flood season shows a remarkable increase except for the continuous decrease in Southwest Guangdong.And the flood and drought becomes more frequent in East Guangdong and Central Guangdong since 1990s.