华北北部半干旱地区夏季大气边界层特征的实验研究

2016年7月3—16日在内蒙古自治区科尔沁地区大气科学与大气环境综合实验站开展科尔沁半干旱下垫面大气边界层野外综合观测试验, 利用 GPS大气边界层精细探空资料, 分析华北北部半干旱地区晴天、阴天和雨天等不同天气条件下的大气边界层结构。采取不同的方法和判据对比确定大气边界层高度, 统计实验期间低空急流特征, 并对近地面湍流特征及地表能量收支状况进行初步的探讨。结果表明: 晴天, 白天的大气边界层平均高度约为1790 m, 夜间约为250 m; 阴天和雨天, 白天的大气边界层平均高度约为980 m, 夜间约为430 m。夜间, 近地面层湍流动能与边界层高度有较强的相关性。低空急流多发生在午夜, 平均高度约为390 m, 强度与高度正相关。

Experimental Research on the Characteristics of the Atmospheric Boundary Layer in the Semi-arid North China

A comprehensive experiment on semi-arid underlying surface was carried out at the comprehensive experimental station of atmospheric science and atmospheric environment in Horqin, Inner Mongolia during July 3th to 16th in 2016. Using high-precision GPS sounding data of the atmospheric boundary layer (ABL), the structure of the ABL in the semi-arid North China under different weather conditions (sunny, cloudy and rainy) was analyzed. The atmospheric boundary layer height (ABLH) was determined by different methods and criteria. In addition, the characteristics of low-level jets (LLJs), surface turbulent flux and surface energy budget were discussed. The results indicate that the average height of the ABL is 1790 m during the day while it is 250 m at night when sunny. In the cloudy day, the average ABLH is 980 m in daytime and 430 m at night. The turbulent kinetic energy in the surface layer shows a strong correlation with ABLH at night. LLJs mostly occur at midnight, with an average altitude of approximately 390 m, and there is a positive correlation between the intensity and the altitude of LLJs.