Future pattern of Asian drought under global warming scenario

Abstract

This study investigates the effect of global warming on drought patterns over Asia at the end of the twenty-first century by a multi-model ensemble method based on daily precipitation data of 15 coupled climate models simulations under SRES A1B scenario, thereby assessing the consistency of responses among different models. The projected precipitation climatology was translated into the change in drought climatology using the effective drought index. The results of the models were consistent in that they project an increase in the mean and the standard deviation of precipitation over most of Asia, and the increase was considerably greater in higher latitude areas. Therefore, it is expected that in future, drought over most of Asia will occur less frequently with weaker intensity and shorter duration than those prevalent currently. However, two special regions were detected. One was the Asian monsoon regions (AMRs: South Asia and East Asia), which showed a greater increase in the standard deviation of precipitation than the mean precipitation, with an amplified seasonal precipitation cycle. As a result, part of the AMRs exhibited slight increases in drought properties such as frequency and intensity. The other region was West Asia. The region showed decreased mean precipitation, especially in its northern part (Syria and its vicinity), and more frequent droughts were projected for this region with enhanced drought intensity and lengthened drought duration. The worsening trends in drought patterns over both regions were more significant in extreme drought, the likelihood of which is relatively higher in summer in West Asia and from spring to summer in the AMRs.