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Responses of Compound Daytime and Nighttime Warm-Dry and Warm-H Events to Individual Anthropogenic ForcingsDaytime heat is often associated with reduced soil moisture and cloud cover, while nighttime heat is connected to high humidity and increased cloud cover. Due to these differing mechanisms, compound daytime and nighttime heat events may respond differently to major anthropogenic forcings (greenhouse gases, anthropogenic aerosols, land-use and land-cover change). Here, we use GISS ModelE2.1-G historical single-forcing runs from 1955 to 2014 to examine how individual anthropogenic forcings affect compound heat events—specifically warm daytime and nighttime temperatures compounded with dry precipitation or high humidity conditions. We show that greenhouse gases alone amplify the natural frequency of warm-dry events by 1.5–5 times and warm-humid events by 2–9 times in tropical and extratropical latitudes. Conversely, aerosols and land-use/land-cover change reduce the frequency of these events, resulting in more modest increases and in some regions, declines, in the historical 'all-forcings' scenario. Individually, aerosol effects are stronger and more widespread compared to land-use, oftentimes reducing the natural frequency of these events by 60%–100%. The responses of these compound events are primarily driven by changes in daytime and nighttime temperatures through large-scale warming via greenhouse gases and cooling from aerosols and land-use/land-cover change. However, changes in warm-dry events are amplified in regions with concurrent precipitation declines (e.g. Central America, Mediterranean regions) and warm-humid events are amplified by global concurrent humidity increases. Additionally, we find differences between daytime and nighttime compound responses in the historical experiment that can be traced back to the individual forcings. In particular, aerosols produce a greater cooling effect on daytime relative to nighttime temperatures, which notably results in a historical reduction of Northern Hemisphere daytime warm-dry events relative to natural conditions. Our analysis provides a more comprehensive understanding of the significant impacts of different anthropogenic climate forcings on daytime and nighttime warm-dry and warm-humid events, informing future risk and impact assessments.
Document ID
20220009149
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Felicia Chiang ORCID
(Goddard Institute for Space Studies New York, New York, United States)
Benjamin I Cook
(Goddard Institute for Space Studies New York, New York, United States)
Sonali McDermid
(New York University New York, New York, United States)
Kate Marvel
(Columbia University New York, New York, United States)
Gavin A Schmidt
(Goddard Institute for Space Studies New York, New York, United States)
Larissa S Nazarenko
(Columbia University New York, New York, United States)
Maxwell Kelley
(Goddard Institute for Space Studies New York, New York, United States)
Date Acquired
June 9, 2022
Publication Date
July 22, 2022
Publication Information
Publication: Environmental Research Letters
Publisher: IOP Publishing
Volume: 17
Issue: 8
Issue Publication Date: August 1, 2022
e-ISSN: 1748-9326
Subject Category
Meteorology And Climatology
Funding Number(s)
WBS: 509496.02.80.01.15
CONTRACT_GRANT: 80HQTR21CA005
CONTRACT_GRANT: 80NSSC20M0282
Distribution Limits
Public
Copyright
Public Use Permitted.
Technical Review
External Peer Committee
Keywords
Anthropogenic forcings
compound climate events
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