三种气象干旱指数在四川省的适用性分析

Applicability Analysis of Three Meteorological Drought Indices in Sichuan Province

受气候和地形等多种因素影响,气象干旱指数在不同地区有着不同的表现。位于长江上游地区的四川省地貌条件复杂,气候类型多样,在使用气象干旱指数进行干旱监测前需要评估其适用性。利用四川省34个气象站点1987~2016年间日降水和日平均气温数据,基于SPI、SPEI和2017年新版国标文件中增加的MCI指数,利用时间序列和空间插值等方法主要对四川省1987~2010年间的干旱过程和干旱年份进行了分析,借助建立的RMSE指标和评分法重点研究了多时间尺度指数反映的干旱强度、干旱范围等与实际旱情的符合度。结果表明:(1)总体上MCI最好,SPI与SPEI效果接近;具体月尺度上,MCI、SPI 3(3个月)、SPEI 3(3个月)是适用性排名的前三位。(2)川东部盆地适合用MCI,川西南山地适合用SPEI 3,川西北高原适合用SPI 6(6个月)或SPI 1(1个月)。(3)SPI、SPEI、MCI指数在川东部盆地的监测误差最小,川西南山地次之,川西北高原最大。

Affected by climate, topography and other factors, meteorological drought index has different performance in different areas. Sichuan Province, located in the upper reaches of the Yangtze River, has complex geomorphic conditions and diverse climate types. Its applicability needs to be evaluated before using the meteorological drought index for drought monitoring. In this paper, we used the daily precipitation and daily mean temperature data of 34 meteorological stations in Sichuan Province from 1987 to 2016. Based on SPI index, SPEI index and MCI index(added in the new national standard document of 2017), by using some methods of time series analysis and spatial interpolation, the drought processes and drought years from 1987 to 2010 were analyzed. By means of the established RMSE(Root Mean Square Error) index and scoring method, the consistency of drought intensity and drought range reflected by multi-time scale indices was mainly studied. The results show that:(1) In general, applicability of MCI index is the best and SPI index is close to the SPEI index;On a specific monthly scale, MCI, SPI 3(3 months), SPEI 3(3 months), are the top three in the applicable ranking.(2) From the perspective of geographical division, the eastern Sichuan Basin is suitable for MCI index, the southwest mountainous area of Sichuan is suitable for SPI 3 index and the northwest Sichuan Plateau is suitable for two indices of SPI 6(6 months) and SPI 1(1 month).(3) The monitoring error of SPI, SPEI and MCI index in eastern Sichuan Basin is the smallest, followed by that in the southwest mountainous area of Sichuan, and the largest in the northwest Sichuan Plateau.