Recently, Dr. Qi Wei, Associate Professor Feng Lian, Associate Professor of School of Environmental Science and Engineering, Southern University of Science and Technology, and Dr. Qi Wei, a chair professor, have been working in geophysical Research Letters (GRL), Environmental Research Letters (ERL), Journal of Hydrology (JoH), and Journal of Geophysical Research: Atmospheres (JGR-A) has published a series of scientific papers on the study of extreme hydrological events and the effects of extreme climate on hydrological processes.
The article, published in GRL, examines the probability of simultaneous extreme drought events in major food-producing countries around the world under global climate change (Figure 1). The results show that: 1. Under extreme climate scenarios, the probability of moderate and severe drought events occurring simultaneously between countries will increase by two times and three times, respectively; 2. Under extreme climates, the probability of moderate and severe drought events between China and the United States, Brazil and Russia will be at least 6% and 5%, respectively; 3. Compared with other climate scenarios, the probability of simultaneous occurrence of severe drought events will be reduced by 2% under the RCP2.6 scenario.
Figure 1 Probability of simultaneous drought in major food-producing countries of the world
The article published in ERL examines the potential changes in flood risk in the Yangtze River Basin (Figure 2) and its influencing factors. The researchers first coupled the hydrological model WEB-DHM-S with the hydrodynamic model CaMa-Flood to form a hydrological hydrodynamic coupling model WEB-DHM-SG that can be used at the global scale; then, the researchers used the WEB-DHM-SG model for flood risk analysis in the Yangtze River Basin. The results show that rapid economic development is the main reason for the increase in potential flood risk in the Yangtze River Basin, and the flood risk caused by extreme weather events has a tendency to decrease without considering economic development.
Figure 2 Spatial distribution of potential flood risk in the middle and lower reaches of the Yangtze River
The article published in JGR-A focuses on the main influencing factors of ice and snow melting in the source areas of southwest rivers and the impacts of extreme climate change (Figure 3). The results show that: 1. The average annual melting of glaciers in the southwest river source area from 1982 to 2011 was 0.32 m w.e., and it was in an accelerating stage; 2. The melting of ice and snow contributed 17.6% of the annual runoff of the southwest river source area (10% from snowmelt and 7.6% from glacier melting), under the influence of extreme climate, this contribution will be reduced to 11.9% in the next 30 years; 3. Temperature, downward long-wave radiation, humidity and wind speed determine the overall trend of glacier melting. Solar radiation affects fluctuations in the rate of glacier melting.
Figure 3 Contribution of melting ice and snow to runoff in the source area of the southwest river
The article published in JoH examines the changes in snowmelt and its effects in northeast China under the influence of extreme climates (Figure 4). The results show that: 1. The rate of winter warming in northeast China is faster than that of spring, and in the 30-year period of 2030-2059, the rate of winter warming will be twice that of spring, and the contribution of snowmelt to spring average and maximum runoff will be reduced by at least 39% and 23% respectively compared with the historical period, and the soil moisture will be reduced by at least 7%; 2. Under extreme climate scenarios, the peak contribution of spring snowmelt to runoff will be advanced from April to March, and the contribution of snowmelt to runoff in May will be reduced to almost zero.
Figure 4 Changes in the contribution of spring snowmelt to runoff in northeast China
Qi Wei, research assistant professor of Liu Junguo's team, is the first author of the 4 papers, Feng Lian is the sole corresponding author of the 4 papers, Liu Junguo and Zheng Chunmiao, chair professors of the Southern University of Science and Technology, Professor Zheng Yi, associate professors Kuang Xingxing and Shi Haiyun, associate professor Tian Yong, associate professor Tian Yong, professor of the Swiss Federal Institute of Water Science and Technology (EAWAG), Chen Deliang, chair professor of the University of Gothenburg in Sweden, Wang Lei, researcher of the Institute of Tibetan Studies of the Chinese Academy of Sciences, and Yao Yingying, associate professor of Xi'an Jiaotong University, are co-authors, and SUSTech is the first unit of the 4 papers. The above research work has been supported by the Strategic Pilot Project of the Chinese Academy of Sciences and the National Natural Science Foundation of China.