1959～2013年海南岛降水事件变化特征

Change Features of Precipitation Events in Hainan Island from 1959 to 2013

运用均匀分布在海南岛的7个国家标准气象站1959~2013年逐日降水量观测数据,采用一元线性趋势、5 a滑动趋势、Mann-Kendall检验、Morlet小波分析、反距离空间插值(IDW)等方法 ,对海南岛大雨和暴雨日数和强度的时空变化特征进行研究。结果表明:(1)尽管大雨和暴雨不是海南岛的主要降水形式,但大雨和暴雨雨量对年降水量的贡献较大,合计超过65%。(2)海南岛平均大雨和暴雨日数在中部山区多、西部沿海少;大雨强度各地差异小,暴雨强度则于西部沿海最强。(3)过去55 a,大雨强度波动减弱趋势微弱,暴雨强度增强趋势显著;大雨和暴雨日数自21世纪以来增多趋势明显。大雨强度、暴雨日数和强度分别在1984年、2004年和1988年前后发生突变。大雨日数和强度的变化周期分别集中在12 a和21 a左右;暴雨日数和强度的变化周期均集中在7、14、21 a左右。(4)大雨日数呈增多趋势的区域主要分布在海南岛东北部和南部,大雨强度于中部山区以北区域呈减弱趋势;暴雨日数增多趋势最明显的区域分布在海南岛西北部和南部,而暴雨强度在东北部和南部增强趋势最明显。

The spatial and temporal variati on of days and intensity of heavy and extreme rainfall were analyzed based on daily precipitation data of seven national standard meteorological stations which were evenly distributed in Hainan Island from 1959 to 2013 by using methods of linear trend, five-years moving trend, Mann-Kendall,Morlet wavelet and Inverse Distance Weighted（ IDW for short）. The results indicated that（i） heavy and extreme rainfall days on a small proportion, however contributed significantly to the annual precipitation for the island during the past 55 years.（ii） The days of heavy rainfall and extreme rainfall were more in middle mountain area of the island than in the western part. Precipitation intensity of heavy rainfall in various places was more uniform,meanwhile extreme rainfall intensity was highest in the western part of the island.（iii） The intensity of heavy rainfall presented a slight decreasing trend while the extreme rainfall intensity had increased significantly during the past 55 years. Both the days of heavy and extreme rainfall had become higher apparently since the early twenty-first century. The heavy rainfall intensity, extreme rainfall days and intensity mutated in 1984, 2004 and1998, respectively. The main cycles of heavy rainfall days and intensity had quasi-periods of 12 years and 21 years respectively, and those of extreme rainfall days and intensity both had quasi-periods of 7 years, 14 years and 21 years.（iv） The increasing rates of heavy rainfall days, extreme rainfall days and intensity were the largest in the northeast and south, northwest and south, and northeast and south of the island respectively, while the decreasing heavy rainfall intensity mainly located in the north of the island.