天津市郊区冬季大气边界层风、温场结构与特征

利用天津市郊区探空观测资料,对该地区冬季大气边界层内的风场、温度场结构与特征进行研究.结果表明,测试期间风向随着高度增加呈顺时针旋转, 由东风、东南风逐渐右转,转为西南风、西风,遵循Eckman螺线的规律;不同高度层风速日变化规律不同.一般来说,在较低高度风速白天变大,夜晚变小,而较高处则相反;接地逆温大约在20:00开始生成,随着时间的增加,逆温逐渐加强,平均逆温厚度在02:00达到最大值;混合层高度在早晨厚度较薄,午后混合层厚度较厚,有利于污染物的扩散;天津市市区10m和100m高度层风速的日变化规律与郊区相同,200m高度层风速日变化规律不同;市区与郊区相比,不同高度层风速随着时间起伏变化较小.

Structures and characteristics of the atmospheric boundary layer in winter of the Tianjin suburb

Based on the observation data that have been obtained, the vertically characteristic of wind field and temperature field in winter of Tianjin city have been studied. The results showed that, during the testing time, the direction of wind as the height increased a clockwise rotation, by East, Southeast gradually turn right, turn to the southwest wind, west wind, following the Eckman spiral pattern; different height level wind changed in the appearance of different laws daily. In general, at low height the wind speed was bigger at the day than the night, but at the more height was contrast; the grounding inverse temperature generated about 20:00. With increasing of the time the inverse temperature enhanced, and on the 02:00 of the second day, the inverse temperature were the most; the height of the mixed boundary was thinner in the early morning, thicker in the afternoon, which was beneficial to the spread of pollutants. The daily variation of the wind speed were the same between the urban and the suburban of the same height at 10m and 100m; but it was different at the 200m; the urban wind speed fluctuation was smaller than the suburb with time daily.