Drought is one of the natural disasters with the widest global impact. The anomalous drought and heatwave event that occurred in the Yangtze River Basin in summer of 2022 is not only of high intensity but also of long duration, it is a rare and significant drought event leading to very serious socioeconomic impacts in China. In view of the extreme nature of this event, this paper reveals the possible influence of atmospheric circulation and external forcing anomalies on this drought event based on an objective analysis of the evolutionary characteristics of this event. It is found that the meteorological drought index and soil moisture monitoring results consistently indicate that this drought event started to appear in June, developed rapidly in July, and further expanded and intensified in both extent and intensity in August. At the same time, the overall temperature in the basin was high, with the number of high temperature days exceeding 40 days in some areas. In addition, anomaly of evapotranspiration over the basin in summer was the second highest on record since 1960, second only to the high temperature drought event in 2013, which further exacerbated the degree of water deficit in the Yangtze River Basin. From the perspective of circulation characteristics, the abnormal intensifying and westward extension of the western Pacific subtropical high pressure, the small area and weak strength of the polar vortex and the intensifying and eastward shift of the South Asian high pressure in summer jointly led to weak water vapor transport conditions and prevailing sinking air currents in the Yangtze River Basin, making the overall conditions unfavorable for the occurrence of precipitation. The persistence of the La Niña event, the appearance of negative Indian Ocean Dipole (IOD) and the persistence of the negative snow cover anomaly in the northwestern Tibet Plateau in spring may be the main external forcing factors leading to the circulation anomaly in this summer.

Drought is one of the natural disasters with the widest impact and the most serious economic losses in China, which directly threatens the country’s food security and socio-economic development. The understanding and research on drought will help to improve the national capacity of drought prevention and mitigation. Since 1949, China’s research on drought meteorology has achieved fruitful results. Based on the research results of the scientific research project group related to drought meteorology carried out by the Key Open Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration since the 21st century, through the achievement retrieval, this paper summarizes the new progress in drought monitoring technology, drought temporal and spatial distribution, drought disaster-causing characteristics, drought disaster risk and its response to climate warming, as well as drought disaster risk management and defense technology. At the same time, based on the frontier development trend of drought meteorology research, on the basis of strengthening the comprehensive drought observation test in drought prone areas under the background of climate change, this paper puts forward that China’s drought meteorology research in future should study quantitatively the formation mechanism of drought from different dimensions and scales, build a new comprehensive drought monitoring method of multi-source data fusion and multi-method combination, reveal the mechanism of drought disaster-causing and evaluate scientifically the drought disaster risk, putting forward the executable risk management strategies. This work is of positive significance to promoting drought meteorological research in China.

According to “the Regulations on Monitoring and Evaluation of Regional Important Processes” issued by China Meteorological Administration in 2019, the basic situations of China’s climate and main meteorological disasters in summer 2021 are comprehensively analyzed based on the meteorological observation data of more than 2400 ground stations in China from 1961 to 2021. The results are as follows: (1) In the summer of 2021, both the average temperature and the average precipitation were higher than that in the same period of the previous years. The rainy season in the north started earlier with enhanced intensity, while it delayed in the south with weakened intensity. These two factors, together with the decreased number of landing typhoons, contributed to the fact that the summer precipitation zones dominated North China. (2) In the summer of 2021, China’s climate conditions were generally worse than normal, the situation of meteorological disasters was complicated and severe, accompanied with frequent occurrences of extreme weather and climate composite events, including flood, heat wave and drought, and moreover, the disasters exhibited periodic and regional features. The number of regional rainstorm processes was 4.9 times lower than that in previous summers, but the extremeness was much stronger. North China, Huanghuai, Jianghan and other places have suffered from severe rainstorms and floods consecutively. Regional high temperature occurred frequently and periodically. The number of regional high temperature processes was 3.4 times higher than that in previous summers, which mainly impacted Huanghai, Jiangnan, South China, the east of Northwest China, the west of Inner Mongolia and the south of Xinjiang. Meteorological droughts appeared in the south and the north simultaneously, with significant regional, periodic and compounding characteristics. And the number of regional drought processes was 1.1 times higher than that in previous summers. South China and Northwest China witnessed the compound development of high temperature and drought.

Considering the different disaster-pregnant environment, population density and economic condition, the drought disaster chain models in southwest and south China were constructed respectively by using history data and record of references. Here, the disaster-pregnant environment includes climate background, underlying surface, landforms, soil and river network. And on this basis that the transmission characteristics of disaster on separate disaster chains were analyzed. The results show that the drought disaster chain structure is similar in southwest and south China, but their transfer process of disaster on the two chain is different. There are obvious regional characteristics of disaster transfer on their chain. The incipient drought can cause crop drought in southwest China, while moderate drought can cause crop drought in south China. In southwest China, the moderate drought can lead to some problems such as people and livestock drinking water difficult and livestock forage shortage, but these corresponding problems can be generated by the severe drought in south China. Being the difference in disaster-pregnant environment, the rock desertification phenomenon appears in southwest China under the severe drought condition, but the probability of rock desertification is small in south China except for north Guangxi. In the same region, as far as the various disaster-affected bodies are concerned, the threshold of drought degree transmitting is different. For example, shipping problems usually result from the moderate drought, and forest fire and pest disaster are often led by the severe drought, while soil degradations appear in the extreme drought.