Title: Constraining Aging Processes of Black Carbon in the Community Atmosphere Model Using Environmental Chamber Measurements

Abstract

Abstract The direct radiative forcing of black carbon aerosol (BC) on the Earth system remains unsettled, largely due to the uncertainty with physical properties of BC throughout their lifecycle. Here we show that ambient chamber measurements of BC properties provide a novel constraint on the crude BC aging representation in climate models. Observational evidence for significant absorption enhancement of BC can be reproduced when the aging processes in the four‐mode version of the Modal Aerosol Module (MAM4) aerosol scheme in the Community Atmosphere Model version 5 are calibrated by the recent in situ chamber measurements. An observation‐based scaling method is developed in the aging timescale calculation to alleviate the influence of biases in the simulated model chemical composition. Model sensitivity simulations suggest that the different monolayer settings in the BC aging parameterization of MAM4 can cause as large as 26% and 24% differences in BC burden and radiative forcing, respectively. We also find that an increase in coating materials (e.g., sulfate and secondary organic aerosols) reduces BC lifetime by increasing the hygroscopicity of the mixture but enhances its absorption, resulting in a net increase in BC direct radiative forcing. Our results suggest that accurate simulations of BC aging processes asmore » well as other aerosol species are equally important in reducing the uncertainty of BC forcing estimation.« less

Authors:

Wang, Yuan  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-6657-8401"

Ma, Po‐Lun  ^[2];

• Search DOE PAGES for author "Ma, Po‐Lun"
• Search DOE PAGES for ORCID "0000-0003-3109-5316"

Peng, Jianfei ^[3]; Zhang, Renyi ^[3]; Jiang, Jonathan H.  ^[4];

• Search DOE PAGES for author "Jiang, Jonathan H."
• Search DOE PAGES for ORCID "0000-0002-5929-8951"

Easter, Richard C.  ^[2];

• Search DOE PAGES for author "Easter, Richard C."
• Search DOE PAGES for ORCID "0000-0002-8602-1464"

Yung, Yuk L. ^[1]

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+ Show Author Affiliations

1. Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA, Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
2. Atmospheric Sciences and Global Change Division Pacific Northwest National Laboratory Richland WA USA
3. Department of Atmospheric Sciences Texas A&,M University College Station TX USA
4. Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA

Publication Date:

Tue Oct 23 00:00:00 EDT 2018

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1478671

Alternate Identifier(s):

OSTI ID: 1478672; OSTI ID: 1510717

Report Number(s):

PNNL-SA-139085
Journal ID: ISSN 1942-2466

Grant/Contract Number:  

AC05-76RL01830; 1700727

Resource Type:

Published Article

Journal Name:

Journal of Advances in Modeling Earth Systems

Additional Journal Information:

Journal Name: Journal of Advances in Modeling Earth Systems Journal Volume: 10 Journal Issue: 10; Journal ID: ISSN 1942-2466

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; black carbon; GCM; aging parameterization; environmental chamber; radiative forcing