An observational study of the effects of aerosols on diurnal variation of heavy rainfall and associated clouds over Beijing–Tianjin–Hebei

Abstract

Abstract. Our previous study found that the observed rainfall diurnal variation over Beijing–Tianjin–Hebei shows the distinct signature of the effects of pollutants. Here we used the hourly rainfall data together with satellite-based daily information of aerosols and clouds to further investigate changes in heavy rainfall and clouds associated with aerosol changes. Because of the strong coupling effects, we also examined the sensitivity of these changes to moisture (specific humidity) variations. For heavy rainfall, three distinguished characteristics are identified: earlier start time, earlier peak time, and longer duration; and the signals are robust using aerosol indicators based on both aerosol optical depth and cloud droplet number concentration. In-depth analysis reveals that the first two characteristics occur in the presence of (absorbing) black carbon aerosols and that the third is related to more (scattering) sulfate aerosols and is sensitive to moisture abundance. Cloud changes are also evident, showing increases in cloud fraction, cloud top pressure, the liquid/ice cloud optical thickness and cloud water path and a decrease in ice cloud effective radius; and these changes are insensitive to moisture. Finally, the mechanisms for heavy rainfall characteristics are discussed and hypothesized.

Distinct impacts on precipitation by aerosol radiative effect over three different megacity regions of eastern China

“…The limited studies regarding the influence of aerosol on precipitation time showed controversial findings in China. Yang et al (2017) found that aerosols show no influence on precipitation time in the Beijing-Tianjin-Hebei region using WRF-Chem model simulations, while Zhou et al (2020) reported that aerosols advance the heavy precipitation start and peak times significantly and prolong the duration of the precipitation in the Beijing-Tianjin-Hebei region. Similar research has been carried out by Guo et al (2016) and Lee et al (2016) in the Pearl River Delta (PRD) region.…”

Global Spatial and Temporal Variation of the Combined Effect of Aerosol and Water Vapour on Solar Radiation

“…Aerosols and water vapour are two major atmospheric components that alter the radiation that reaches the Earth's surface on clear-sky days through scattering and absorption processes [3][4][5]. Their effects on the surface solar radiation are assorted, causing, for example, diurnal and seasonal temperature oscillations [6], changes in the surface energy balance [7] or the water cycle [8][9][10][11]. In addition, atmospheric water vapour influences the radiometric properties of the aerosol and, therefore, their effects on the downwelling surface solar radiation, impacting climate and climate change.…”

Observational Quantification of Aerosol Invigoration for Deep Convective Cloud Lifecycle Properties Based on Geostationary Satellite

“…Aerosols can significantly affect the updrafts, precipitation, and electrification of DCC (Altaratz et al, 2014;Tao et al, 2012;Zhao et al, 2018). Aerosols nucleate a larger number of smaller cloud drops, which leads to delay of rain initiation to greater heights, more evaporation, cooling and moistening aloft at the expense of less evaporation, and cooling at the low levels (Zhou et al, 2020). Dagan et al (2017) and Chua and Ming (2020) showed that the resultant enhanced thermal instability and mixing with more humid ambient air could invigorate the convection.…”