西南涡对气溶胶光学厚度变化特征的影响研究

Influences of southwest vortex on aerosol optical depth variation

为研究西南涡对气溶胶光学厚度(AOD)的影响,本研究利用2008-2010年的西南涡个例数据与对应时间段的中分辨率成像光谱仪(MODIS)卫星遥感观测AOD数据,并结合降水量、风速、相对湿度、温度等气象资料进行了分析研究.结果发现,2008-2010年产生干涡31个,强降水涡29个,弱降水涡26个.总体而言,干涡过境后使AOD增加而降水涡过境后使AOD减少,且弱降水涡比强降水涡削减作用强.春季产生的西南涡对AOD的影响最大,夏季产生的干涡过境后会使AOD减少,夏季的弱降水涡过境后会使AOD增加.不同季节产生的不同类型西南涡过境后致使AOD变化的主导气象因子不同.总体而言,较大的风速对AOD具有显著的削减作用;干涡中较小的风速、温度和相对湿度是使AOD增加的主要因素;弱降水涡中较大的风速和产生的降水是使AOD减少的主要因素,但夏季产生的弱降水涡中影响AOD的主要因素是风速、温度和湿度;强降水涡中无明显的主导因素.

In order to study the influence of the southwest vortex on aerosol optical depth(AOD), the southwest vortex case data from 2008-2010, the corresponding AOD data of the medium-resolution imaging spectroradiometer(MODIS) satellite remote sensing, and meteorological data(i.e. precipitation, wind speed, relative humidity and temperature) had been analyzed. It was found that from 2008 to 2010, there were 31 dry vortices, 29 strong precipitation vortices and 26 weak precipitation vortices. In general, the AOD is increased after the dry vortices transiting, and the AOD is decreased after the precipitation vortices transiting. The AOD decreased effect after weak precipitation vortices transiting is stronger than that of the strong precipitation vortices. In spring, the southwest vortices has the greatest impact on AOD. In summer, the AOD decreased after the passage of dry vortices, while increased after the passage of weak precipitation vortices. The dominant meteorological factors causing AOD change are different after the passage of different types of southwest vortices produced in different seasons. Small wind speed, low temperature and low relative humidity in the dry vortices are the main factors contributing to the increase of AOD;the larger wind speed and precipitation in the weak precipitation vortices are the main factors that reduce AOD, but the main factors affecting AOD in the weak precipitation vortices generated in summer are wind speed, temperature and humidity;there is no obvious dominant factor in the strong precipitation vortices.