苏州城区大气边界层低空急流特征分析

利用2012年苏州城区风廓线雷达的观测资料,从低空急流个例分析入手,选取1、4、7、10月四个典型月份,分析该地区边界层低空急流的时空分布及强度变化特征。结果表明:冬春两季低空急流发生频率最高,夏季出现频率最低。在4个典型月份里低空急流均表现出日落后出现频率升高,夜间保持稳定,日出后出现频率降低的特征。全年有80%的低空急流分布在900 m以下高度上,冬、夏季平均高度最低。全年低空急流风速70%以上集中在4~12 m·s~(-1),小于4 m·s~(-1)和大于20 m·s~(-1)的低空急流出现频率较低。

Analysis on low-level jet in atmospheric boundary layer in Suzhou

Based on the wind profile radar observation data of Suzhou in 2012, the four typical months (January, April, July and October) were selected to study the temporal-spatial distribution and intensity variation of planetary boundary low-level jet from the aspect of case analysis on low-level jet. Results show that the low-level jet occurred most in winter and spring and least in summer. The frequency of low-level jet increased after sunset, remained stable at night, then decreased after sunrise. 80% low-level jets occurred below 900 m height, and the mean height of occurrence was the lowest in summer and winter. More than 70% low-level jet amounted to 4-12 m·s^-1. The low-level jet smaller than 4 m·s^-1 and greater than 20 m·s^-1 rarely happened.