基于MCI的河南干旱时空变化特征分析

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》干旱标准，计算得到各站点近48年逐日气象干旱综合指数（MCI）。基于MCI指数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：近48年来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；近48年来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，除冬季外其它三个季节干旱发生的范围有逐渐加大的趋势。

Characteristics of spatiotemporal variation of drought in Henan based on Meteorological Drought Composite Index

According to the meteorological industry standard of classification of meteorological drought, daily meteorological drought composite index(MCI) of 110 stations in Henan from 1971-2018 were calculated using historic daily air temperature and rainfall. Based on MCI index, the annual and seasonal characteristics were analyzed in this paper, 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, in recent 48 years, the annual average drought days in Henan Province presented the gradual increase from south to north. The annual average drought days of light and moderate grades in north areas were more than that in south areas. Seasonally, the average drought days in spring, summer and winter were more in north that in south. In Recent 48 years, the ratio of drought stations changed greatly. The frequency of regional drought was the highest in this area. The drought areas in Henan Province showed an increasing trend, especially in spring, summer and autumn seasons.