The variation of cloud amount and light rainy days under heavy pollution over South China during 1960\u20132009

Chuanbo Fu,Li Dan

doi:10.1007/s11356-017-0510-4

Abstract

The ground observation data was used to analyze the variation of cloud amount and light precipitation over South China during 1960–2009. The total cloud cover (TCC) decreases in this period, whereas the low cloud cover (LCC) shows the obvious opposite change with increasing trends. LCP defined as low cloud cover/total cloud cover has increased, and small rainy days (< 10 mm day−1) decreased significantly (passing 0.001 significance level) during the past 50 years, which is attributed to the enhanced levels of air pollution in the form of anthropogenic aerosols. The horizontal visibility and sunshine duration are used to depict the anthropogenic aerosol loading. When horizontal visibility declines to 20 km or sunshine duration decreases to 5 h per day, LCC increases 52% or more and LCP increases significantly. The correlation coefficients between LCC and horizontal visibility or sunshine duration are − 0.533 and − 0.927, and the values between LCP and horizontal visibility or sunshine duration are − 0.849 and − 0.641, which pass 0.001 significance level. The results indicated that aerosols likely impacted the long-term trend of cloud amount and light precipitation over South China.

Highlights

Interaction between aerosol, cloud, and precipitation has become one of the frontiers in the atmospheric science (Lohmann and Lesins 2002; Penner et al 2004)
It was argued that surface observations of cloud amount and light precipitation were influenced by the aerosol indirect effect over South China (Duan and Liu 2011)
The result shows that an obvious opposite change trends for total cloud cover (TCC) and low cloud cover (LCC) were found during the past 50 years over South China

Summary

Introduction

Interaction between aerosol, cloud, and precipitation has become one of the frontiers in the atmospheric science (Lohmann and Lesins 2002; Penner et al 2004). High concentration of aerosol particles in the cloud retards the process of warm rain effectively. The main method currently used to study the aerosol effect on cloud and precipitation depends on the satellite data (Ferek et al 1998; Rosenfeld 2000; Heymsfield and Environ Sci Pollut Res (2018) 25:2369–2376. Yin and Chen (2007) used a dynamic cloud model with detailed microphysics of both warm and ice phase processes, and found that dust aerosol could transform to cloud condensation nucleus (CCN) and ice nucleus (IN), affected cloud and precipitation. The aim of this study is to explore the impact on light precipitation and cloud amount by aerosol particles over South China in the past 50 years. Statistic methods of regression analysis, tendency fit, and correlation analysis (Wei 2007) were used in this study

Result analysis

Findings

Conclusions and discussions