干旱形成机制与预测理论方法及其灾害风险特征研究进展与展望

Progress and prospect of the research on drought formation,prediction,and related risk assessment

在全球变暖背景下,干旱事件发生的频率和强度不断增大、影响不断加重,干旱发生规律的异常性和机制的复杂性也更为突出,对干旱形成机制、预测理论方法及灾害风险变化规律等方面都提出了新的挑战,也制约了当前干旱预测、预警及其灾害防控能力的提高。近年来,在国家重点基础研究发展计划(973计划)课题等多个国家级项目支持下,已在干旱灾害形成机制与预测理论方法及其风险特征方面取得了一系列新成果。通过动力诊断、数值模拟和田间试验等方法,开展了干旱形成的多因子协同作用和多尺度叠加机制、干旱致灾过程的逐阶递进特征,以及干旱灾害风险分布演化的主控因素等方面的研究。对如下几方面的新进展进行了系统总结归纳:(1)厘清了全球变暖背景下青藏高原热力、海温、夏季风、遥相关等多因子对干旱形成的作用机制。(2)发现了降水亏缺时间尺度和农作物不同生长阶段的干旱敏感性规律。(3)揭示了变暖背景下典型区域干旱灾害风险分布及其变异的新特征;构建了干旱灾害风险新概念模型。(4)研发了东亚季风区的季节和次季节干旱集成预测系统。在总结归纳已取得研究成果的基础上,对未来干旱形成机制及其灾害风险科学研究进行了展望,提出了5个重点研究方向:(1)多因子联动及其多尺度叠加效应对干旱形成的影响;(2)系统整合人类活动和决策以及相关反馈的气候模式研究;(3)揭示陆-气耦合和大气环流协同作用对干旱的影响;(4)认识干旱灾害对粮食安全和生态安全影响的关键过程;(5)提高不同气候情景下干旱预估的准确度。

Under the background of climate warming,the frequency and intensity of droughts are increasing.The regularity of drought occurrence and the complexity of its formation mechanism are becoming more prominent,which poses new challenges to the mechanism study on drought formation,the theory and method of drought prediction and changes in disaster risk.They also restrict improvements on current drought prediction,early warning,disaster prevention and control ability.In recent years,with the support of several national projects such as the National Key Basic Research and Development Program(973 Program),a series of new achievements have been made in the studies of formation mechanism,prediction theory and risk characteristics of drought disaster.This paper systematically summarizes recent progress in the following aspects:(1)Clarified the mechanism of Qinghai-Xizang plateau heating,sea temperature,summer monsoon,remote correlation and other factors on the formation of drought.(2)Found the sensitivity of crops at different growth stages and temporal drought scale to precipitation deficit.(3)Revealed new characteristics of drought disaster risk distribution and variation in typical regions under the background of warming,and constructed a new conceptual model of drought disaster risk.(4)Developed the integrated forecast system of seasonal and sub-seasonal drought in East Asian monsoon area.On the basis of summarizing the existing research results,future research on drought formation mechanism and disaster risk is proposed,and five key research directions are put forward:(1)influences of multi-factor linkage and multi-scale superposed effect on drought formation;(2)studies on climate models that systematically integrate human activities and decisions with their associated feedbacks;(3)effects of land-atmosphere coupling and atmospheric circulation on drought;(4)knowledge of the key process of drought disaster impact on food security and ecological security;(5)research on improving the accuracy of drought prediction under different climate scenarios in the future.