无霾和有霾情况下大气混合层高度的日变化及其特征——基于河北香河站激光雷达的观测

The Diurnal Variation and Characteristics of the Atmospheric Mixed Layer Height in Haze and Non-haze Days——Based on LIDAR Observation in Xianghe,Hebei

利用Mie散射激光雷达EZLidar和自动观测站气象资料对河北香河站2006年8月~2007年11月大气混合层高度（MLH）进行了观测研究,得出了灰霾和非灰霾两种天气大气混合层的日变化特征：1 MLH的日变化同温度、风速的变化密切相关,相关系数分别为0.968、0.580,通过了0.01的置信度检验;2春季的MLH明显高于秋、冬两个季节,秋冬两季混合层的发展相似,MLH较低,大体上秋季的MLH高于冬季;3灰霾天气溶胶含量高,阻挡地面长波辐射向外发射,形成了类似的保温效应,灰霾天大气温度要高于非霾天的温度,且随着时间的增加而增加;4灰霾天属于静稳天气,热力引起的湍流非常弱,风速变化对它的影响更大。热力和机械剪切作用共同影响了灰霾天和非灰霾天MLH的日变化。

The mixed layer height（ MLH） in Xianghe,Hebei was observed and studied based on Mie scattering lidar EZ lidar and automatic observatory meteorological data from August 2006 to November 2007. The diurnal variation of the MLH in haze and fine days are obtained： 1 The diurnal variation of MLH was closely related with the change of air temperature and wind speed,with the correlation coefficient was 0. 968 and 0. 580 respectively,and passed the test of confidence level of 0. 01; 2 MLH in spring was obviously higher than that in autumn and winter,the development of mixed layer was similar in autumn and winter,in general,MLH was higher in autumn than winter; 3 The high loading of aerosol in haze weather prevented the ground long-wave radiation from emitting outward,the heat preservation effect made the temperature in haze days higher than that in fine days and the difference increased over time; 4 As the haze weather was in a state of static stability and the turbulence caused by heat was very weak,the change of wind speed had a greater impact on the development of MLH. The diurnal variation of MLH in haze and fine days were affected both by thermal and mechanical shearing action.