不同RCP情景下未来汉江流域气象干旱变化趋势预估研究

采用来自国际比较计划CMIP5的5个全球气候模式(GCMs)数据，同时这些模式数据也是跨行业影响模式比较计划(ISIMIP)采用的气候模式数据，以RCP2.6和RCP8.5两种情景下的日降雨预估数据，计算了汉江流域不同时段的标准化降水指数(SPI)，以此作为预估未来干旱变化趋势的主要依据。以汉江流域22个气象站点的降雨量观测数据(1960~2004年)和2020~2059年气候模式数据，对比分析了这两个时期干旱事件发生的严重程度、次数和历时特征。结果表明：在干旱严重程度方面，轻度干旱和中度干旱有减轻的趋势，但严重干旱有加重的趋势。由于不同GCMs模拟能力的差异性，对干旱事件的发生次数和历时的分析有一定差异，但总体仍表现为干旱次数减少和历时减短的趋势。通过对比历史时期降水观测数据和GCMs模式预估数据评估结果，表明HadGEM2-ES模式对降水的拟合性最好，而GFDL-ESM2M和IPSL-CM5A-LR在干旱方面表现出较好的模拟能力。

Research on Projection of Meteorological Droughts in the Hanjiang River Basin Under Different RCPs Scenarios

In this paper the daily precipitation data from five global climate models (GCMs), which are all from CMIP5 and also the input in the Inter-Sectoral Impact Model Inter-comparison Project (ISIMIP), under RCP2.6 and RCP8.5 scenarios respectively in the Hanjiang River Basin is used to project the drought changes in the area through Standard Precipitation Index (SPI) at different time scales. Based on the observed data from 22 meteorological stations in Hanjiang River Basin in 1960-2004, and the GCM data in 2020-2059, three characters related to the drought events in these two durations, including drought severity, frequency and duration are compared and analyzed. Results show that in the drought severity the light or moderate drought events will happened less while the severe drought events can arise more often. As to the frequency and duration it is difficult to draw an identical conclusion from different GCMs. Anyway there is a general tendency in less frequency and shorter duration in the future. Through the comparison between the historical observed data and GCM generated data, HadGEM2-ES shows better performance in the rainfall simulation while GFDL-ESM2M and IPSL-CM5A-LR have better results in the less-rainfall namely drought analysis.