loading page

Analysis of the Characteristics of the Boundary Layer Jet in the Middle reaches of the Yangtze River during the Meiyu season
  • +5
  • Chunguang Cui,
  • Wen zhou,
  • Hao Yang,
  • Xiaokang Wang,
  • Yi Deng,
  • Xiaofang Wang,
  • Guirong Xu,
  • Jingyu Wang
Chunguang Cui
Institute of Heavy Rain, China Meteorological Administration
Author Profile
Wen zhou
Institute of Heavy Rain, China Meteorological Administration

Corresponding Author:zhouwen_zhouw@163.com

Author Profile
Hao Yang
Institute of Heavy Rain, China Meteorological Administration´╝îWuhan
Author Profile
Xiaokang Wang
Institute of Heavy Rain, China Meteorological Administration
Author Profile
Yi Deng
Georgia Institute of Technology
Author Profile
Xiaofang Wang
Institute of Heavy Rain, China Meteorological Administration
Author Profile
Guirong Xu
Institute of Heavy Rain, China Meteorological Administration
Author Profile
Jingyu Wang
Institute of Heavy Rain, China Meteorological Administration
Author Profile

Abstract

The Low-level Jet (LLJ) in the Yangtze River Basin during the Meiyu season is analyzed and studied mostly as the atmospheric circulation background of precipitation, which cannot adequately reflect the characteristics of the jet itself. In this paper a fusion of sounding observations and precipitation data from Wuhan Station during the Meiyu season in 2010 are used to analyze the characteristics of the LLJ in the middle reaches of the Yangtze River. The results show that: the vertical structure of the LLJ is characterized by the predominance of a Boundary-layer Jet (BLJ) with an occurrence height concentrated in the 300-1200 m. The BLJ occurs most frequently at 22:00 at night, but most strongly at 01:00 at night, with resultant wind velocities exceeding 14 m/s. A Synoptic-system-related Low-Level Jet (SLLJ) occurs most frequently at 07:00 during the day, but most strongly at 10:00, with resultant wind velocities exceeding 12 m/s. For both the BLJ and SLLJ, the wind direction is characterized by southwesterly winds. However, the wind direction of the SLLJ is more westerly relative to the BLJ, and the northeasterly direction of the SLLJ occurs significantly more frequently. The analysis of four typical cases of heavy precipitation in the middle reaches of the Yangtze River shows that before the onset of heavy precipitation, a LLJ exists in the precipitation center and at its south side. The SLLJ is dominated by southwesterly winds, and the BLJ has more southerly wind component with the BLJ developing earlier than the SLLJ.