内蒙古气溶胶光学厚度时空特征及其气象因子响应研究

Study on the Space-Time Characteristics of Aerosol Optical Thickness and Its Meteorological Factor Response in Inner Mongolia

随着大气环境的恶化,愈来愈多的研究学者研究了很多关于气溶胶的研究。影响大气环境的因素雾霾其实上可以说是由各种原因所形成的气溶胶。气溶胶光学厚度(aerosol optical thickness, 简称AOT)或(aerosol optical depth, 简称AOD)表示的是电磁波在单位截面的垂直气柱上的透过率,可以用气溶胶来表示空气中的混浊程度。AOD作为气候与环境变化的关键性因子,它所能够影响的气象要素有很多。本文利用MODIS气溶胶产品数据,分析了2017年至2020年内蒙古地区气溶胶光学厚度时空分布特征,再结合National Oceanic and Atmospheric Administration (NOAA)气象数据,进一步分析了气溶胶光学厚度对气象因子的响应,从而得知以下结论:1) 在空间分布上:气溶胶光学厚度高值分布在兴安盟、通辽、赤峰东部区和阿拉善、鄂尔多斯等西部区,内蒙古东西两端,北纬47˚以南,其主要原因为此地区沙漠较多,远离海洋,湖泊干枯,湿地消失,植被退化,周围群山环抱,生物多样性减少,常年干旱多降雨少;低值分布在巴彦淖尔到锡林郭勒盟的中部区和高纬度呼伦贝尔地区,其主要原因为这部分地区常年下雨的次数多,草原多,人类活动也比较其他城市少。植被覆盖度高,生物多样性,从而导致空气污染少。2) 在时间分布上:气溶胶光学厚度高值主要分布在3、4、5、6月份,其主要原因为沙尘暴季节、植被覆盖返青期从而导致污染程度高;低值主要分布8、9、10月份,其主要原因为植被生长期,覆盖度高从而空气质量好。3) 对气象因子的响应上:风速对气溶胶光学厚度的影响最高,正相关,即风速越大气溶胶光学厚度越高;降水和气溶胶光学厚度,表现弱相关,即降水量越大气溶胶光学厚度越高;相对湿度跟气溶胶表现为显著负相关,空气湿度越高,空气质量好,从而气溶胶光学厚度的值就低。

With the deterioration of the atmospheric environment, more and more researchers have studied aerosols. Aerosol optical thickness (AOT) or aerosol optical depth (AOD) is the rate of penetration of electromagnetic waves on vertical columns of the unit cross-section, which can be used to indicate the degree of turbidity in the air. Using MODIS aerosol product data, this paper analyzes the space-time distribution characteristics of aerosol optical thickness in Inner Mongolia from 2017 to 2020, and then combines NOAA meteorological data to further analyze the response of aerosol op-tical thickness to meteorological factors, so as to learn the following conclusions: 1) In the spatial distribution: The high value of aerosol optical thickness is distributed in Xing’an League, Tongliao, Chifeng East and Alashan, Ordos and other western regions, Inner Mongolia east and west ends, north latitude 47 degrees south. The main reason is that the desert in this area is more far from the ocean, full of dry lakes, lost wetlands and degraded vegetation, surrounded by mountains, with reduced biodiversity, year-round drought and less rainfall;The low values is in the central region of Bayangar to Xilin Guolemen and the high-latitude Hulun Buir region. The main reason is that in this area, there is more rainfall and grassland, and human activities are less than other cities, and high vegetation cover and biodiversity lead to less air pollution. 2) In the time distribution: aerosol opti-cal thickness is mainly distributed in March, April, May and June. The main reasons are sandstorm season, vegetation yellowing period leading to high pollution levels;The low values are mainly distributed in August, September and October, and the main reason is the vegetation growth period, high coverage and good air quality. 3) Response to meteorological factors: Wind speed has the highest effect on aerosol optical thickness, significantly positive correlation, that is, the higher the wind speed, the higher the aerosol optical thickness. There is a weak correlation between precipitation and aerosol optical thickness, that is, the greater the precipitation, the higher the aerosol optical thickness. There is a significant negative correlation between relative humidity and aerosol. The higher the air humidity is, the better the air quality is, so the value of aerosol optical thickness is lower.