基于MCI的河南干旱时空变化特征分析

Characteristics of Spatiotemporal Variation of Drought in Henan Based on Meteorological Drought Composite Index

利用1971-2018年河南110个气象站点逐日逐日气温和降水量等资料,根据《气象干旱等级》国家标准(GB/T 20481-2017),计算得到各站点(1971-2018年)逐日气象干旱综合指数(MCI)。基于MCI分析了历年平均干旱日数、各等级干旱年平均干旱日数、各季节平均干旱日数和干旱站次比的年变化、季节变化特征。结果表明:1971-2018年,河南年平均干旱日数整体趋势自南向北逐渐增加,轻旱、中旱等级干旱年平均日数呈北多南少趋势,春季、夏季和冬季平均干旱日数呈北多南少趋势;干旱站次比的变化范围较大,区域性干旱在该地区出现的频率最高,河南干旱发生的范围有加大的趋势,除冬季外,其他三个季节干旱发生范围呈逐渐加大的趋势。

According to the National Standard GB/T 20481-2017 of classification of meteorological drought, daily meteorological drought composite index(MCI) were calculated using historic daily data of 110 weather stations in Henan from 1971 to 2018. Then the annual and seasonal characteristics were analyzed, including the annual average drought days, the average drought days in different grades, the average drought days in each season and the ratio of drought stations. The results showed that, from 1971 to 2018, the annual average drought days in Henan Province presented the gradual increase from south to north. The annual average days of light drought and moderate drought in north areas were more than those in south areas. Seasonally, the average drought days in spring, summer and winter were more in north areas and lese in south areas. There were large variation ranges of the ratio of drought stations. Regional drought had high occurrence in Henan.The drought areas in Henan Province present an increasing trend, especially in spring, summer and autumn seasons.