Effect of aerosols on the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region

Tongqiang Liu; Qiong Liu; Yonghang Chen; Wencai Wang; Hua Zhang; Dui Li; Jun Sheng

doi:10.1016/j.scitotenv.2020.137618

Effect of aerosols on the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region

Sci Total Environ. 2020 Jun 10:720:137618. doi: 10.1016/j.scitotenv.2020.137618. Epub 2020 Feb 28.

Authors

Tongqiang Liu¹, Qiong Liu², Yonghang Chen³, Wencai Wang⁴, Hua Zhang⁵, Dui Li¹, Jun Sheng¹

Affiliations

¹ College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
² College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address: liuqiong@dhu.edu.cn.
³ College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address: yonghangchen@dhu.edu.cn.
⁴ Key Laboratory of Physical Oceanography, College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China.
⁵ State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China.

PMID: 32146402
DOI: 10.1016/j.scitotenv.2020.137618

Abstract

The interaction between aerosols and clouds plays an important role in the climate system. There is still uncertainty about the influences of aerosols on the macro- and micro-physical properties of clouds in the Beijing-Tianjin-Hebei region. The relationships between aerosol optical depth (AOD) and the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region were analyzed based on MODIS/Aqua data from 2007 to 2016. In addition, the ERA-Interim meteorological data was employed to investigate the relationship of AOD and cloud parameters under different meteorological conditions. The results showed that the variation of cloud droplet effective radius (CER) with AOD was in agreement with the Anti-Twomey effect, the main reason was that the increasing aerosol causes the water vapor competition effect among the cloud droplets, which makes the smaller cloud droplets evaporate. The multi-year average AOD was positively correlated with liquid water path (LWP). The relationship between AOD and cloud optical depth (COD) was quite different. When AOD was <0.4 or >0.8, COD increased with the increase of AOD, and when AOD was between 0.4 and 0.8, AOD and COD showed negative correlation. With the increment of AOD, cloud top pressure (CTP) also increased, which indicated that cloud top height decreased. When AOD was <0.3, cloud fraction (CF) was negatively correlated with AOD and conversely, positively correlated when AOD was >0.3. Furthermore, under most meteorological conditions, AOD was positively correlated with cloud macro- and micro-physical properties. Under the conditions of relative humidity ranged from 40% to 80%, there was a negative correlation between AOD and COD.

Keywords: AOD; Cloud macro-parameters; Cloud micro-parameters; Meteorological conditions.