Title: Impacts of Suppressing Excessive Light Rain on Aerosol Radiative Effects and Health Risks

Abstract

Global climate models (GCMs) have been used widely to study radiative forcing and health risks of aerosols. A recent study using two GCMs found that light rain plays a dominant role in controlling aerosol loading. However, “too much light rain and too little heavy rain” is a longstanding bias in GCMs. It is unclear how much light rain affects aerosol-cloud-radiation interactions and health risks from air pollution. Here, in this work, we show that, with the correction of the rainfall intensity spectrum in the National Center for Atmospheric Research Community Atmosphere Model version 5.3 by introducing a stochastic deep convection scheme, the reduced frequency of light rain (1–20 mm d^-1) results in changes of aerosol direct radiative effects (DRE) of up to -0.5 ± 0.03 W/m² and aerosol cloud radiative effects (CRE) of up to -0.9 ± 0.03 W/m². The total (CRE + DRE) radiative effects of light rain-mediated aerosol changes exceed the present-day anthropogenic forcing of aerosols relative to preindustrial levels from the Coupled Model Intercomparison Project (CMIP5&6) models. However, the correction of the rainfall intensity spectrum has little effect on anthropogenic aerosol forcing (defined as the radiative perturbation due to changes in aerosol concentrations between the industrial eramore » and preindustrial levels). Due to increased exposure to fine particulates (PM_2.5), the estimated global total premature mortality is much higher than previously estimated, by 300,000 ± 60,000 deaths per year, and is more severe in populous regions such as India and China. The findings in this study highlight the need to understand uncertainties in radiative effects and health risks of aerosols due to simulation biases of precipitation in GCMs.« less

Authors:

Wang, Yong  ^[1];

• Search DOE PAGES for author "Wang, Yong"
• Search DOE PAGES for ORCID "0000-0002-5831-9466"

Xia, Wenwen  ^[1];

• Search DOE PAGES for author "Xia, Wenwen"
• Search DOE PAGES for ORCID "0000-0002-4615-6188"

Zhang, Guang J.  ^[2];

• Search DOE PAGES for author "Zhang, Guang J."
• Search DOE PAGES for ORCID "0000-0002-9712-5226"

Wang, Bin  ^[3];

• Search DOE PAGES for author "Wang, Bin"
• Search DOE PAGES for ORCID "0000-0001-7374-3786"

Lin, Guangxing  ^[4]

• Search DOE PAGES for author "Lin, Guangxing"
• Search DOE PAGES for ORCID "0000-0002-5443-3915"

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+ Show Author Affiliations

1. Tsinghua Univ., Beijing (China)
2. Scripps Institution of Oceanography, La Jolla, CA (United States)
3. Tsinghua Univ., Beijing (China); Chinese Academy of Sciences (CAS), Beijing (China)
4. Chinese Academy of Sciences (CAS), Beijing (China)

Publication Date:

Tue Apr 26 00:00:00 EDT 2022

Research Org.:

Univ. of California, San Diego, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); National Key Research and Development Program of China; National Natural Science Foundation of China (NSFC)

OSTI Identifier:

1978551

Grant/Contract Number:  

SC0022064; 2017YFA0604000; 41975126

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research: Atmospheres

Additional Journal Information:

Journal Volume: 127; Journal Issue: 9; Journal ID: ISSN 2169-897X

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; stochastic deep convection parameterization; light rainfall; aerosol radiative effects; aerosol health risks