Progress and prospect on the study of causes and variation regularity of droughts in China

Droughts are one of the most serious and extensive natural disasters in the world. As a typical monsoon climate area, China is particularly affected by drought disasters. A great deal of researches on droughts have been carried out in the world, and studies have been evolved from qualitative and presentative understandings to quantitative descriptions of objective characteristics and in-depth exploration of the formation mechanism. Since the founding of the People's Republic of China, considerable progresses have been made in the field of drought research from sporadic studies of some major drought events to gradual integration with international drought studies. However, there is no objective and clear understanding of scientific progresses of drought research and the insight of the development direction of drought research is insufficient. Based on comprehensive understanding of the current status of international drought research, this paper systematically reviews the history of drought research in China since the founding of the People's Republic of China, summarizes important progresses on drought research in China, and divides the progress into four major stages: Characteristics and spatial and temporal distributions of drought events, formation mechanisms and change regularities of droughts, drought disaster risks, and occurrences of flash droughts. This paper also summarizes important achievements of drought researches in China in view of the characteristics of drought events, the spatial and temporal distribution of droughts, the change rules of droughts, the causes of droughts, the influencing mechanisms of droughts, the formation process of drought risks, the response of droughts to climate warming and the particularity of sudden droughts. Moreover, in combination with the international cutting-edge studies and hotspot issues and development trend of drought research, this paper scientifically analyzes the weaknesses and problems of drought researches in China, and proposes that China needs to make breakthroughs on six major scientific issues in the future, including the multi-factor synergetic effect on drought formation, the effect of land-atmosphere interaction on drought formation and development, the identification, monitoring and prediction of flash droughts, the transmission rules and non-uniform characteristics among various types of droughts, the effect of critical impacting period on agricultural drought development, the complexity of drought response to climate warming, and the scientific assessment of drought disaster risks on the basis of strengthening the comprehensive drought science experiment research in typical areas frequently affected by droughts.