State of the climate in the Three Gorges Region of the Yangtze River basin in 2020

In 2020, the average air temperature in the Three Gorges Region (TGR) of the Yangtze River basin was 17.2°C, which was close to normal, there were exceptionally fewer days than normal with high temperatures, and the high-temperature events mainly occurred in August. Meanwhile, the average precipitation was 1530.8 mm, which was a remarkable 29% more than usual, and the second-highest since 1961. The precipitation was obviously above-normal in summer, and the precipitation in both June and July was the second-highest of the same period in history. The average number of rainstorm days was higher than normal, and the second-highest since 1961. The average wind speed in the TGR was apparently higher than normal; the average relative humidity was slightly higher than normal; and there were no instances of acid rain, with the rain acidity showing a significant weakening trend over the previous 15 years. In the summer of 2020, the TGR experienced heavy rainstorms and flood disasters. Analysis shows that the frequent southward movement of cold air and abundant warm water vapor from the southwest were the direct causes of the abnormally high precipitation in the TGR from June to July. After the spring of 2020, the continuously high sea surface temperature in the Indian Ocean led to a continuously strong western Pacific subtropical high and its average location being situated more to the south than normal, which might have been an important cause for the abnormal climate conditions in the Yangtze River basin from June to July.