ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 49 Issue 10 > 2023,49(10):1267-1276. DOI:10.7519/j.issn.1000-0526.2023.072001 Prev Next
Features and Possible Causes of Abnormal Climate over China in Spring 2023
- Article
- Figures
- Metrics
- Preview PDF
- Reference
- Related
- Cited by
- Materials
Abstract:
In the springtime (March to May, MAM) of 2023, the mean temperature in China was 11.5℃, the seventh highest in history since 1961. The temperature in most of China was higher than normal except that in Xinjiang, the western part of Northwest China and Tibet was lower than normal. The national average precipitation was 132.7 mm, which is 7.4% less than normal. The precipitation showed a feature of “more in the north and less in the south”, with more precipitation in North China, Huanghuai Region and QinghaiTibeteau Plateau but significantly less in Northeast China, the eastern part of the region south the Yangtze River, South China, and Southwest China. In the spring (MAM) of 2023, a “two ridges and one trough” circulation was found to be distributed in the middle and high latitudes of Eurasia. In the middle troposphere, the positive height anomaly center was at the Ural Mountains area, the negative height anomaly center was from the Lake Baikal to Lake Balkhash area, and the 〖JP2〗geopotential height field was posi〖JP〗tive anomaly over Northeast Asia. The western Pacific subtropical high was weaker than normal. In the lower troposphere, an abnormal cyclonic circulation maintained in the tropical western Pacific, while in its north there was an abnormal anticyclone circulation. The high ridge index in Northeast Asia in MAM 2023 was 1.7, exceeding one standard deviation. It is the fourth highest index since 1961, and is favorable for more precipitation in northern China. Affected by the anticyclone circulation, the area to the north of the Yangtze River had an abnormally strong southeasterly wind, which was conducive to the transport of the warm and wet water vapor from the Northwest Pacific to the northern region of China. A weak La Ni〖AKn~D〗a event began in September 2021 in the equatorial central and eastern Pacific and lasted until March 2023. In April 2023, the sea surface temperature (SST) in the equatorial central and eastern Pacific began to shift to a warmer phase. In MAM 2023, precipitation in northern China was affected by the evolution of SST in the equatorial Pacific. The composite analysis showed that in the spring when the SST changed from cold to warm, the circulation anomaly of “two ridges and one trough” was prone to appear in the midlatitude region of Eurasia, and the cold air blowed southward influencing China. Meanwhile, the anticyclone anomaly was found over East Asia, making the southeast wind anomaly prevail in northern China, and more water vapor was transported from the Northwest Pacific to northern China, providing favorable conditions for more precipitation in the region.
Keywords:
Project Supported:
Clc Number:
Mobile website
