近50年辽宁省极端气候事件的趋势变化及空间特征

为明确辽宁省近50年极端气候事件的趋势变化特征以及时空分布情况,本文以辽宁省1964—2015年逐日平均气温、最低气温、最高气温以及降水数据为基础,选取省域范围内的23个气象站点,依据世界气象组织(WMO)确定的"气候变化检测和指标",选取适用于研究区的8个极端气温指数和4个降水指数,采用线性趋势法、Mann-Kendall突变检验法及反距离加权插值法,分析近50年来辽宁省极端气温和降水事件的时空演变特征。结果表明:时间尺度上,表征极端高温事件的极端最高温、夏日日数、暖昼、暖夜日数逐渐增多且在未来一段时间具有持续上升趋势;极端低温事件指数如霜冻日数、冷昼数、冷夜数均表现为下降趋势变化;极端降水指数除普通日降水强度较为平稳外均呈上升趋势,辽宁省极端降水事件增加。空间尺度上,极端最高温、最低温、霜冻日数、夏日日数呈由北向南递减的规律,冷夜、冷昼、暖夜、暖昼数呈不规律分布。与降水量相关的极端降水指数呈南高北低,东高西低的格局。

Trend variation and spatial characteristics of extreme climate events in Liaoning Province in recent 50 years

In order to define the characteristics of the trend variation and the temporal-spatial distribution of the extreme climate events in Liaoning Province in recent 50 years，23 meteorological stations in the province are selected on the basis of the data of the annual daily mean temperature，lowest temperature，highest temperature and precipitation from 1964 to 2015，while 8 extreme temperature indexes and 4 precipitation indexes adaptable for the study area are chosen in accordance with the Climate Change Detection and Index confirmed by the World Meteorological Organization (WMO)，and then the temporal-spatial evolution characteristics of the extreme temperature and precipitation events in Liaoning Province in recent 50 years are analyzed herein with linear trend method，Mann-Kendall mutation test and inverse distance weighted interpolation method. The result shows that from temporal scale，the characterizing extreme high temperature events，such as extreme high temperature，day number of summer，day numbers of both warm day and warm night，are to be gradually increased with continuous increasing trends in a period of time in the future and all the indexes of the extreme low-temperature events，i. e. number of frost days，number of cold days， and number of cold nights，present the variations of decreasing trends，while all the extreme precipitation indexes exhibit increasing trends except the more smooth precipitation intensity of common day，thus the extreme precipitation events in Liaoning Province are increased. On the spatial scale，the extreme highest temperature，lowest temperature，frost days，day number of summer show the laws of descending from the north to the south，while cold nights，cold days，warm nights and warm days show the irregular distributions. The extreme precipitation indexes related to precipitation show the patterns of high in the south and low in the north as well as high in the east and low in the west.