Weather and climate are important factors that affect economic and social development. The National Climate Center (NCC) of China releases an annual climate report every year, which comprehensively reflects the achievements and progress in climate system monitoring and climate impact assessment in China. This series of reports has been published in Atmospheric and Oceanic Science Letters for four consecutive years since 2019, with the “State of China's climate in 2021” the most recently published.

Dr. Li Wei, Director of the Climate Services Division of the NCC, summarizes and classifies the main characteristics of China’s climate as well as high-impact weather and climate events in 2021 as follows: “After 2020, China’s climate in 2021 showed obvious warm and wet characteristics again. The annual mean air temperature was 10.5℃ over China, which was 1.0℃ above the climatology of 1981–2010 and broke the historical record since 1951. Annual precipitation in China was 672.1 mm, which was 6.7% above normal. Meanwhile, annual precipitation in northern China was more than 40% above normal, and ranked second highest since 1951.”

According to the report, in 2021, the annual climate anomaly in China was generally worse than normal, waterlogging was more serious than drought, and extreme weather and climate events occurred frequently. The rainstorm intensity in the rainy season was strong and featured significant extremes. For instance, torrential rain in Henan Province caused severe economic losses and human fatalities. The maximum hourly rainfall in Zhengzhou City broke the historical record for mainland China. Continuous precipitation in the Yellow River basin induced autumn floods. Heat waves occurred more frequently than normal, with their duration in southern China being longer than normal in summer and autumn. Phased drought was obvious and caused serious impacts in South China. The number of generated and landfalling typhoons was lower than normal. However, Typhoon In-fa broke the record for the longest overland duration since 1949 and affected a wide area. Extreme winds induced by severe convective weather occurred frequently, with serious consequences. The number of cold waves was more than normal, which caused extreme low temperature in many places. Sandstorms appeared earlier than normal in 2021, and the number of strong dust storm processes was more than normal.

A particular feature of 2021 was that the rainy season in South China and Southwest China, and the mei-yu season, all started later and ended earlier than normal, with deficient precipitation. Conversely, the rainy season in North China, the autumn rains in West China, and the rainy season in Northeast China all started earlier and ended later than normal, with abundant rainfall. For example, from 1 January to 29 September 2021, the average precipitation in Beijing was 862.9 mm, which was 68.9% more than that in the same period in normal years, which ranked the highest for the same period since 1961. The consequences of this excessive rainfall are illustrated in the photograph below.

Jinhai Lake, Pinggu District, Beijing, in early September. Due to abundant precipitation, the water level of the lake rose significantly, with some steps of the sightseeing steps submerged, and some trees on the shore flooded to the trunk. (Credit by Li Wei)

“According to statistics from the Ministry of Civil Affairs, the affected crop area and number of human fatalities and missing persons in 2021 decreased significantly, and direct economic losses were slightly smaller, as compared to the average in the past decade,” concludes Li.

Link:

https://doi.org/10.1016/j.aosl.2022.100211

Citation:

Wei Li, Shanshan Zhao, Yu Chen, Ling Wang, Wei Hou, Yundi Jiang, Xukai Zou, Shuai Shi, 2022. State of China's climate in 2021. Atmospheric and Oceanic Science Letters, https://doi.org/10.1016/j.aosl.2022.100211