气象科学2024，Vol.44Issue(5)：899-906,8.DOI:10.12306/2023jms.0009
北京地区边界层低空急流的时空发展特征分析
Temporal and spatial characteristics of the low-level boundary layer jet over Beijing
摘要
Abstract
In this study,based on the 2018-2019 Doppler Lidar data and Micaps data,the seasonal variation,diurnal variation and evolution characteristics of the Low-Level Jet(LLJ)in Beijing area were discussed.In addition,the frequency of LLJ in the boundary layer under different weather systems was analyzed statistically.Results show that:(1)the LLJ in the boundary layer over Beijing shows obvious seasonal differences.The daily occurrence frequency of LLJ in spring,summer and winter was 56.2％,52.3％and 54.8％,respectively,and in autumn,it was the highest,which was 79.4％.And the phenomenon of multi-LLJ process in a single day exists in all seasons.The height of LLJ axis shows a single peak state.The frequency of the LLJ in spring and winter is inversely proportional to the height,while the LLJ in autumn and winter mostly occurs within the 200-400 m peak.The intensity of the LIJ in Beijing is mainly weak jet,mainly concentrated around 5-9 m·s-1.The LLJ is weak in spring,autumn and winter,but is stronger in summer.(2)The LLJ in the boundary layer in Beijing shows obvious diurnal variation.Nearly 89.5％of the LLJ occurred at night,and the LLJ occurred during the day mainly concentrated in the morning,with a frequency of 7.6％.Statistics show that this part of the LLJ is mainly the continuation of the night jet.(3)According to its development characteristics,the boundary layer LLJ over Beijing can be divided into five types:meridian type,uplift type,subsidence type,intermittent type and weak wind speed zone type.(4)The weather conditions with multiple jet streams can be divided into six types:high pressure control,high pressure front,high pressure back,high pressure bottom,high pressure top and uniform pressure field,and the LLJ frequency was 11.1％,9.5％,7.9％,6.3％,15.9％and 38.1％.关键词
边界层低空急流/季节特征/日变化特征/急流分型/天气分型Key words
LLJ/seasonal characteristics/diurnal variation characteristics/jet stream classification/weather classification分类
天文与地球科学引用本文复制引用
王嘉鑫,王成刚,严家德,李炬..北京地区边界层低空急流的时空发展特征分析[J].气象科学,2024,44(5):899-906,8.基金项目
国家自然科学基金面上资助项目(41975011) （41975011）
