Multi-Source Data Based Investigation of Aerosol-Cloud Interaction Over the North China Plain and North of the Yangtze Plain

Although great progress has been made in the study of aerosol-cloud interactions (ACIs), representation of ACI is still the largest uncertainty in current weather and climate models. In this study, the ACI over the North China Plain and north of the Yangtze Plain is investigated using multi-source data including satellite, ground-based, reanalysis, and fusion data. The effects of aerosol characteristics (PM2.5, PM10, and PM2.5/PM10 ratio), atmospheric conditions including liquid water path (LWP) and lower tropospheric stability (LTS), and drizzle on ACI are analyzed. Results suggest that both aerosol characteristics and atmospheric conditions can affect cloud effective radius (re), but drizzle in clouds plays a decisive role on ACI. In the case of fixed LTS and LWP, the average cloud droplet re increases first and then fluctuates for all clouds examined with the increase of PM2.5 concentration. The PM2.5 concentration corresponding to the turning point of re increases with the increasing LWP due to the increased chance of collision and coalescence. In contrast, the average cloud droplet re and PM2.5 concentration show a negative correlation for clouds without drizzle, which is mainly caused by competition of water vapor. The quantitative ACI results show that the values of the aerosol first indirect effect are negative for most cases when considering all clouds examined, but positive when only considering clouds without drizzle.

Automated summary

This study investigates aerosol-cloud interactions over the North China Plain and north of the Yangtze Plain, finding that aerosol characteristics, atmospheric conditions, and drizzle all have impacts on cloud effective radius. Results show that the aerosol first indirect effect is negative for most cases when considering all clouds, but positive when only considering clouds without drizzle.