Impact of aerosols on precipitation from deep convective clouds in eastern China

Abstract

We analyzed the impact of aerosols on precipitation based on 3 years of 3-hourly observations made in heavily polluted eastern China. The probability of precipitation from different cloud types was calculated using International Satellite Cloud Climatology Project cloud data and gauge-based hourly precipitation data. Because deep convective clouds have the largest precipitation probability, the influence of aerosols on the precipitation from such clouds was studied in particular. Aerosol properties were taken from the Modern-Era Retrospective Analysis for Research and Applications Aerosol Reanalysis data set. As aerosol optical depth increased, rainfall amounts from deep convective clouds increased at first and then decreased. The descending part of the trend is likely due to the aerosol radiative effect. Downwelling solar radiative fluxes at the surface decreased as aerosol optical depth increased. The decrease in solar radiation led to a decrease in ground heat fluxes and convective available potential energy, which is unfavorable for development of convective clouds and precipitation. The tendencies for lower cloud top temperatures, lower cloud top pressures, and higher cloud optical depths as a response to larger aerosol optical depths suggest the invigoration effect. Vertical velocity, relative humidity, and air temperature from the National Centers for Environmental Prediction Climate Forecast System Reanalysis were sorted to help investigate if the trends are dependent on any environmental conditions. How dynamic and microphysical factors strengthen or mitigate the impact of aerosols on clouds and precipitation and more details about their interplay should be studied further using more observations and model simulations.

Declining frequency of summertime local‐scale precipitation over eastern China from 1970 to 2010 and its potential link to aerosols

“…Intriguingly, there exhibits a boomerang pattern for the variation of the LSP frequency with aerosol loading, indicative of a nonlinear relationship between LSP and aerosols: positive first and negative after. This phenomenon is consistent with the boomerang shape revealed by satellite observations [ Koren et al ., ; Wang et al ., ], surface observations [ Jiang et al ., ], and theoretical calculations [e.g., Feingold et al ., ; Rosenfeld et al ., ].…”

Aerosol and monsoon climate interactions over Asia

“…Using a combination of satellite and ground‐based measurements, Jiang et al . [] examined the influences of aerosol on precipitation via altering surface fluxes, atmospheric stability, and aerosol invigoration. They found evidence of these mechanisms, as well as the dependence on rainfall regimes.…”

Multiscale Variability of Meiyu and Its Prediction: A New Review

“…It was noted that changes in urbanization (Fu, 2003) and atmospheric composition (Ramanathan & Feng, 2009) associated with anthropogenic factor can alter the monsoon rainfall. And heavy rain has been found to increase with increasing aerosol loading through aerosol indirect effects on deep convective clouds (e.g., Fan et al, 2013; Jiang et al, 2016; Li et al, 2011; Qian et al, 2009; Rosenfeld et al, 2008; Yang & Li, 2014), due to invigoration of convection and/or enhanced ice microphysical processes. Different from the observed trend in total rainfall, both the frequency and amount of light rain have decreased in eastern China from 1956 to 2005, suggesting that the significantly increased aerosol concentrations produced by air pollution are at least partly responsible for the decrease in light rain events (Guo et al, 2017; Qian et al, 2009; Yang et al, 2013).…”