宁夏典型沙尘天气条件下气溶胶分布特征研究

Temporal and Spatial Distribution of Atmospheric Aerosol in Typical Dusty Weather over Ningxia

利用2006-2010年期间云—大气气溶胶激光雷达红外探索卫星(CALIPSO)星载激光雷达(CALIOP)数据和宁夏地区常规气象观测资料,分析研究了典型沙尘天气条件下宁夏地区大气气溶胶光学性质的分布特征。结果表明:CALIPSO资料能有效地反映宁夏地区沙尘气溶胶相关特性的垂直分布特征。在沙尘天气下,处于贺兰山背风坡海拔较高区域的沙尘可以被抬升到对流层中层以上,近地层大气中主要以粗粒子为主,不规则的非球形气溶胶随着高度的增加而增加,高层大气中以波长比在0.4~2.0之间的粗粒子为主、退偏比在0.4以上的不规则非球形气溶胶在7 km、10 km左右高度出现极大值,这与沙尘天气下湿度垂直分布廓线相一致。在晴空天气条件下,退偏比均在0.2以下,波长比主要在0.2~0.4之间,且两者出现频率随高度的变化较小。在沙尘天气下宁夏地区气溶胶光学厚度主要分布在0.60~2.00之间,晴空天气下主要分布在0.33~0.43之间。

By using the CALIPSO data and the observation data from 2006 to 2010,the temporal and spatial distribution of atmospheric aerosols in different condition over Ningxia was analyzed. The results showthat the CALIPSO can effectively detect the distribution of dusty aerosol. Under the dust- storm weather condition,in the leeward slope of Helan Mountain,the dust in the highest area can be up to the middle of tropospheric layer,the coarse particle proportion is given priority to,the non- spherical particle present increasing trend with the altitude increasing,in the higher layer,the particle which is non- spherical and coarse is the maximum,which is same as the relative humidity profile. In the sunny day,the value of the depolarization ratio was less than 0. 2,the value of wavelength ratio between 0. 2 and 0. 4 is given priority to,the depolarization ratio and wavelength ratio in each range were constant with the change of height. In the dust- storm weather condition,the value of Aerosol Optical Depth( AOD) is between 0. 6 and 2. 0. In the sunny day,the value of AOD is between 0. 33 and0. 43.