Black Carbon Increases Frequency of Extreme ENSO Events

Journal Article · Sun Dec 01 00:00:00 EST 2019 · Journal of Climate

DOI:https://doi.org/10.1175/JCLI-D-19-0549.1· OSTI ID:1573871

Lou, Sijia ^[1]; Yang, Yang ^[2]; Wang, Hailong ^[1]; Lu, Jian ^[1]; Smith, Steven J. ^[3]; Liu, Fukai ^[4]; Rasch, Philip J. ^[1]

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1. Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington
2. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China
3. Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, Maryland
4. Physical Oceanography Laboratory/CIMST, Ocean University of China, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China

El Niño–Southern Oscillation (ENSO) is the leading mode of Earth’s climate variability at interannual time scales with profound ecological and societal impacts, and it is projected to intensify in many climate models as the climate warms under the forcing of increasing CO₂ concentration. Since the preindustrial era, black carbon (BC) emissions have substantially increased in the Northern Hemisphere. But how BC aerosol forcing may influence the occurrence of the extreme ENSO events has rarely been investigated. In this study, using simulations of a global climate model, we show that increases in BC emissions from both the midlatitudes and Arctic weaken latitudinal temperature gradients and northward heat transport, decrease tropical energy divergence, and increase sea surface temperature over the tropical oceans, with a surprising consequential increase in the frequency of extreme ENSO events. A corollary of this study is that reducing BC emissions might serve to mitigate the possible increasing frequency of extreme ENSO events under greenhouse warming, if the modeling result can be translated into the climate in reality.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); National Natural Science Foundation of China (NSFC)
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1573871
• Alternate ID(s): OSTI ID: 1580514
• Report Number(s): PNNL-SA-141442
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Vol. 32 Journal Issue: 23; ISSN 0894-8755
• Publisher: American Meteorological Society
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ENSO
Climate models
Aerosol radiative effect
Primary aerosol