The clustering of severe and sustained droughts in Southwest China (SWC) during the last decade has resulted in tremendous losses, including crop failure, a lack of drinking water, ecosystem destruction, health problems, and even deaths. Various attempts have been made to explore the variability and causes of drought in SWC. Here, the authors summarize and integrate this accumulated but fragmented knowledge. On the whole, general agreement has been reached on the evolution of drought in SWC, which has become more frequent and intense during the past 50 years and is projected to continue throughout the 21st century. However, it is unclear and even disputable as to what and how sea surface temperatures and circulation oscillation patterns affect the drought condition. Meanwhile, the presence of strong nonlinearity places considerable challenges in both understanding and predicting drought in SWC. Therefore, much remains to be learned concerning the mechanisms responsible for drought disasters in SWC and accurate forecast practice. In addition to pursuing research on factors and processes involved in drought formation, above all, there is an urgent need to develop appropriate strategies and plans for mitigating the threats of drought.
最近十几年，中国西南地区出现了极端干旱事件频发的态势，对当地的农业、水资源、生态系统以及社会经济造成了严重的影响。西南干旱已成为政府和学术界高度关注的热点问题，国内外学者针对中国西南干旱事件开展了一系列的研究工作。虽然该领域的研究进展较快，但仍缺乏综合性和系统性，因此作者对中国西南干旱的科研成果和发展动态进行了系统的归纳和总结，并希望对今后的研究有所启示。目前而言，对西南干旱的研究主要可以分为两类：一是对西南地区过去和未来干旱演变特征的分析和预估，二是对西南干旱事件发生的大尺度环流背景和成因分析。研究表明，过去50年，西南干旱事件发生的频率增加、强度也增强，而且干旱风险在21世纪很可能将继续增加。但是关于西南干旱成因和预估的一些关键问题还存在争议，特别是海洋强迫和大气环流异常影响西南干旱的过程和机制尚不完全清楚。同时，复杂的非线性相互作用对理解和预测西南干旱也构成严峻的挑战。尽管目前对西南干旱事件发生规律和机理的认识有限，但采取措施有效应对干旱的影响已刻不容缓。