1956—2020年海南岛极端降雨气候及旱雨季变化趋势分析

Analysis of the Trend of Extreme Climate and Dry and Rainy Seasons on Hainan Island in the Last 65 Years(1956-2020)

研究围绕国家气象信息中心提供的1956—2020年海南岛5个气象站点的日降雨数据,通过气候要素倾向率法、累计距平法和Mann-Kendall非参数检验法分析诊断其变化特征,并着重检验了旱季(12月—来年3月)与雨季(4月—11月)分界线,以及4月和11月的降雨年际变化。结果表明,海南岛近65年极端降雨量与极端降雨频次都呈现上升趋势,极端降雨事件主要集中在雨季并具有逐年连续性;旱季最长无有效降雨天数呈上升趋势,降雨量增加趋势极小,旱季干旱程度在逐年加剧。4月降雨量呈现上升趋势,11月降雨量呈现下降趋势,旱雨季均呈现前移趋势,即提前到来、提前结束的趋势。对比筛选极端降雨事件前后的4月和11月降雨量,极端降雨对旱雨季划分影响极小。此外,总体降雨量呈上升趋势且增加量集中在雨季。

This study focuses on the daily rainfall data of five meteorological stations on Hainan Island from 1956 to 2020 provided by the National Meteorological Information Center.The climate element tendency rate,cumulative anomaly,and Mann Kendall non-parametric test are employed to analyze their change characteristics.The results showed that the extreme rainfall and the frequency of extreme rainfall on Hainan Island over the last 65 years had shown an increasing trend,with extreme rainfall events concentrated in the wet season and year-to-year continuity.It has the maximum number of days without effective rainfall in the dry season.The increasing trend of rainfall is insignificant,and the dry season drought is increasing year-to-year.Rainfall in April shows an increasing trend,and rainfall in November shows a decreasing trend.The dry and rainy seasons both show a trend towards a forward shift ahead of arrival and end.Comparing the April and November rainfall before and after the screening of extreme rainfall events,extreme rainfall has minor impact on the division of the dry and rainy seasons.In addition,the overall rainfall showed an upward trend and the increase was concentrated in the rainy season.