ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 44 Issue 4 > 2018,44(4):572-581. DOI:10.7519/j.issn.1000-0526.2018.04.011 Prev Next
Analysis of Characteristics and Causes of Precipitation Anomalies over Northern China in Autumn 2017
- Article
- Figures
- Metrics
- Preview PDF
- Reference
- Related
- Cited by
- Materials
Abstract:
The stage characteristics of precipitation over China in the autumn of 2017 is obvious, and the significantly above-normal precipitation over northern China from September to October was mainly influenced by the East Asia circulation pattern anomaly. The distribution of 500 hPa height anomaly field in East Asia was “+-+” from high to low latitude. The polar height field was higher than normal, the polar vortex split and inclined to Northeast Asia, the area between Baikal Lake and Balkhash Lake was under a significantly low trough, and the West Pacific subtropical high was stronger, stretching more westward and northward than normal, which is favorable to the intensive autumn rainfall in West China. In addition, anticyclonic circulation anomaly over Korean Peninsula was conducive to guiding the cold and wet airflow along the easterly path to the area between the Yellow River and the Yangtze River, and to converging with the warm and wet airflow from the Bay of Bengal and the South China Sea. The water vapor flux convergence resulted in precipitation anomalies in the Huanghuai and Jianghuai regions. Further diagnosis shows that the tropical Middle East Pacific sea surface temperature turned cold in autumn, and the Walker circulation in the tropical Pacific increased obviously, which is beneficial to the westward and northward extension of the stronger West Pacific subtropical high. The positive phase of the tropical Indian Ocean dipole in September-October was favorable for the formation of anticyclonic circulation anomalies in the Bay of Bengal, and also beneficial to the westward and northward extension of the West Pacific subtropical high. Therefore, the influence of the external forcing signal of sea surface temperature and the circulation anomaly in the middle and high latitudes over East Asia led to more precipitation over northern China.
Keywords:
Project Supported:
Clc Number:
Mobile website
