Seasonal Loops Between Local Outgoing Longwave Radiation and Surface Temperature
Name
10.1029-2021GL092978.pdf
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1.74 MB
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Checksum (MD5)
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Author(s)
Richards, Benjamin D. G.
Koll, Daniel D. B.
Cronin, Timothy W.
Date Issued
August 6, 2021
Journal
Geophysical Research Letters
Publisher
American Geophysical Union (AGU)
Citation
Richards, B. D. G., Koll, D. D. B., & Cronin, T. W. (2021). Seasonal loops between local outgoing longwave radiation and surface temperature. Geophysical Research Letters, 48, e2021GL092978.
Version
Author's final manuscript
Abstract
The relationship between outgoing longwave radiation (OLR) and the surface temperature has a major influence on Earth's climate sensitivity. Studies often assume that this relationship is approximately linear, but it is unclear whether the approximation always holds. Here we show that, on seasonal timescales, clear-sky OLR is a multivalued function of local surface temperature. In many places, the OLR-temperature relationship is better approximated by a loop than a line and we quantify the resulting “OLR loopiness”, that is, how much clear-sky OLR varies between different seasons with the same surface temperature. Based on offline radiative calculations, in the tropics OLR loops are mainly caused by seasonal variations in relative humidity that are out of phase with surface temperature; in the extratropics, OLR loops are mainly due to variations in lapse rates. Our work provides a mechanism through which Earth's climate feedback can differ between seasonal and long-term time scales.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2021gl092978
