基于可变模糊评价模型的长江上游气象干旱评价

Comprehensive Assessment of Meteorological Drought Based on the Variable Fuzzy Evaluation Model in the Upper Reaches of Yangtze River Basin

为全面评价长江上游流域的气象干旱状况,利用该流域1953~2012年的气温、降水资料,选取标准化降水指数(SPI)、连续无雨日(CDD)、相对湿润度指数(M)3种气象干旱指标,建立可变模糊数学模型,并应用Mann-Kendall检验法和小波分析方法分析了该流域长期气象干旱的时空变化特征。结果表明,流域气象干旱程度总体呈加重趋势;季节上冬、春连旱较为严重,秋旱有显著加重趋势,预计今后出现秋、冬、春连旱的可能性大;气象干旱存在20年左右的长周期以及6~8年左右的短周期;年际及季节空间分布规律均为自东向西逐渐加重。研究成果可为深入认识区域长期气象干旱演变特征提供参考,对西南等地区的抗旱减灾工作具有重要意义。

In order to comprehensively evaluate the meteorological drought in the upper reaches of the Yangtze River, based on the temperature and precipitation data from 1953 to 2012, a variable fuzzy model was established by choosing three drought indices including Standardized Precipitation Index, Consecutive Rainless Days and Relative Humidity Index. Moreover, the characteristics of spatial-temporal variation in the study region were analyzed by Mann-Kendall and wavelet analysis methods. The results show that the meteorological drought in this basin becomes more severe; The drought intensity in winter and spring was more severe, and the drying trend was more obvious in autumn; It was predicted that the drought from winter to spring was especially likely to happen. The annual change of the meteorological drought show 20 years long cycle and 6-8 years short cycle; The annual and seasonal spatial distribution patterns were both characterized as a gradually increasing trend from east to west. Therefore, the research findings can provide a more comprehensive drought evaluation system and play an important role in making drought resistance strategy in southwest China and other regions.