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Warming effect of dust aerosols modulated by overlapping clouds below

Xu, Hui and Guo, Jianping and Wang, Yuan and Zhao, Chuanfeng and Zhang, Zhibo and Min, Min and Miao, Yucong and Liu, Huan and He, Jing and Zhou, Shunwu and Zhai, Panmao (2017) Warming effect of dust aerosols modulated by overlapping clouds below. Atmospheric Environment, 166 . pp. 393-402. ISSN 1352-2310 . http://resolver.caltech.edu/CaltechAUTHORS:20170728-073938165

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Abstract

Due to the substantial warming effect of dust aerosols overlying clouds and its poor representation in climate models, it is imperative to accurately quantify the direct radiative forcing (DRF) of above-cloud dust aerosols. When absorbing aerosol layers are located above clouds, the warming effect of aerosols strongly depends on the cloud macro- and micro-physical properties underneath, such as cloud optical depth and cloud fraction at visible wavelength. A larger aerosol-cloud overlap is believed to cause a larger warming effect of absorbing aerosols, but the influence of overlapping cloud fraction and cloud optical depth remains to be explored. In this study, the impact of overlapping cloud properties on the shortwave all-sky DRF due to springtime above-cloud dust aerosols is quantified over northern Pacific Ocean based on 10-year satellite measurements. On average, the DRF is roughly 0.62 Wm^(−2). Furthermore, the warming effect of dust aerosols linearly increases with both overlapping cloud fraction and cloud optical depth. An increase of 1% in overlapping cloud fraction will amplify this warming effect by 1.11 Wm^(−2)τ^(−1). For the springtime northern Pacific Ocean, top-of-atmosphere cooling by dust aerosols turns into warming when overlapping cloud fraction is beyond 0.20. The variation of critical cloud optical depth beyond which dust aerosols switch from exerting a net cooling to a net warming effect depends on the concurrent overlapping cloud fraction. When the overlapping cloud coverage range increases from 0.2 to –0.4 to 0.6–0.8, the corresponding critical cloud optical depth reduces from 6.92 to 1.16. Our results demonstrate the importance of overlapping cloud properties for determining the springtime warming effect of dust aerosols.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.atmosenv.2017.07.036DOIArticle
http://www.sciencedirect.com/science/article/pii/S1352231017304776PublisherArticle
ORCID:
AuthorORCID
Zhao, Chuanfeng0000-0002-5196-3996
Additional Information:© 2017 Elsevier Ltd. Received 14 March 2017, Revised 18 July 2017, Accepted 19 July 2017, Available online 21 July 2017. This work was supported by the Natural Science Foundation of China (NSFC) under grant 41590874, the National Key Research and Development Program of the Ministry of Science and Technology (MOST) of China (2016YFA0602003), NSFC (Grants 91544217, 41405035 and 41471301), MOST under grant 2015DFA20870, the Postdoctoral Science Foundation of China (2016M601196), and Chinese Academy of Meteorological Sciences under grants 2017Z005 and 2017R001. We are grateful to NASA for make us freely get access to the CALIOP and MODIS data used here. Last, but not least, we would like to thank the editor and three anonymous reviewers for their constructive comments, which help significantly to improve the quality of this manuscript.
Funders:
Funding AgencyGrant Number
Natural Science Foundation of China41590874
Ministry of Science and Technology (China)2016YFA0602003
Natural Science Foundation of China91544217
Natural Science Foundation of China41405035
Natural Science Foundation of China41471301
Ministry of Science and Technology (China)2015DFA20870
Postdoctoral Science Foundation of China2016M601196
Chinese Academy of Meteorological Sciences2017Z005
Chinese Academy of Meteorological Sciences2017R001
Subject Keywords:CALIPSO; Cloud; Dust aerosol; Radiative forcing
Record Number:CaltechAUTHORS:20170728-073938165
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20170728-073938165
Official Citation:Hui Xu, Jianping Guo, Yuan Wang, Chuanfeng Zhao, Zhibo Zhang, Min Min, Yucong Miao, Huan Liu, Jing He, Shunwu Zhou, Panmao Zhai, Warming effect of dust aerosols modulated by overlapping clouds below, Atmospheric Environment, Volume 166, October 2017, Pages 393-402, ISSN 1352-2310, https://doi.org/10.1016/j.atmosenv.2017.07.036. (http://www.sciencedirect.com/science/article/pii/S1352231017304776)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79525
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Jul 2017 14:49
Last Modified:06 Mar 2018 17:36

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