Sources of Intermodel Spread in the Lapse Rate and Water Vapor Feedbacks
Abstract
Abstract Sources of intermodel differences in the global lapse rate (LR) and water vapor (WV) feedbacks are assessed using CO2 forcing simulations from 28 general circulation models. Tropical surface warming leads to significant warming and moistening in the tropical and extratropical upper troposphere, signifying a nonlocal, tropical influence on extratropical radiation and feedbacks. Model spread in the locally defined LR and WV feedbacks is pronounced in the Southern Ocean because of large-scale ocean upwelling, which reduces surface warming and decouples the surface from the tropospheric response. The magnitude of local extratropical feedbacks across models and over time is well characterized using the ratio of tropical to extratropical surface warming. It is shown that model differences in locally defined LR and WV feedbacks, particularly over the southern extratropics, drive model variability in the global feedbacks. The cross-model correlation between the global LR and WV feedbacks therefore does not arise from their covariation in the tropics, but rather from the pattern of warming exerting a common control on extratropical feedback responses. Because local feedbacks over the Southern Hemisphere are an important contributor to the global feedback, the partitioning of surface warming between the tropics and the southern extratropics is a key determinantmore »
- Authors:
-
- Lawrence Livermore National Laboratory, Livermore, California
- Department of Atmospheric Sciences, and School of Oceanography, University of Washington, Seattle, Washington
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE; National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
- OSTI Identifier:
- 1633937
- Alternate Identifier(s):
- OSTI ID: 1438795
- Report Number(s):
- LLNL-JRNL-739332
Journal ID: ISSN 0894-8755
- Grant/Contract Number:
- AC52-07NA27344; NNX13AN49G
- Resource Type:
- Published Article
- Journal Name:
- Journal of Climate
- Additional Journal Information:
- Journal Name: Journal of Climate Journal Volume: 31 Journal Issue: 8; Journal ID: ISSN 0894-8755
- Publisher:
- American Meteorological Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; Climate change; Climate sensitivity; Climate models
Citation Formats
Po-Chedley, Stephen, Armour, Kyle C., Bitz, Cecilia M., Zelinka, Mark D., Santer, Benjamin D., and Fu, Qiang. Sources of Intermodel Spread in the Lapse Rate and Water Vapor Feedbacks. United States: N. p., 2018.
Web. doi:10.1175/JCLI-D-17-0674.1.
Po-Chedley, Stephen, Armour, Kyle C., Bitz, Cecilia M., Zelinka, Mark D., Santer, Benjamin D., & Fu, Qiang. Sources of Intermodel Spread in the Lapse Rate and Water Vapor Feedbacks. United States. https://doi.org/10.1175/JCLI-D-17-0674.1
Po-Chedley, Stephen, Armour, Kyle C., Bitz, Cecilia M., Zelinka, Mark D., Santer, Benjamin D., and Fu, Qiang. Fri .
"Sources of Intermodel Spread in the Lapse Rate and Water Vapor Feedbacks". United States. https://doi.org/10.1175/JCLI-D-17-0674.1.
@article{osti_1633937,
title = {Sources of Intermodel Spread in the Lapse Rate and Water Vapor Feedbacks},
author = {Po-Chedley, Stephen and Armour, Kyle C. and Bitz, Cecilia M. and Zelinka, Mark D. and Santer, Benjamin D. and Fu, Qiang},
abstractNote = {Abstract Sources of intermodel differences in the global lapse rate (LR) and water vapor (WV) feedbacks are assessed using CO2 forcing simulations from 28 general circulation models. Tropical surface warming leads to significant warming and moistening in the tropical and extratropical upper troposphere, signifying a nonlocal, tropical influence on extratropical radiation and feedbacks. Model spread in the locally defined LR and WV feedbacks is pronounced in the Southern Ocean because of large-scale ocean upwelling, which reduces surface warming and decouples the surface from the tropospheric response. The magnitude of local extratropical feedbacks across models and over time is well characterized using the ratio of tropical to extratropical surface warming. It is shown that model differences in locally defined LR and WV feedbacks, particularly over the southern extratropics, drive model variability in the global feedbacks. The cross-model correlation between the global LR and WV feedbacks therefore does not arise from their covariation in the tropics, but rather from the pattern of warming exerting a common control on extratropical feedback responses. Because local feedbacks over the Southern Hemisphere are an important contributor to the global feedback, the partitioning of surface warming between the tropics and the southern extratropics is a key determinant of the spread in the global LR and WV feedbacks. It is also shown that model Antarctic sea ice climatology influences sea ice area changes and southern extratropical surface warming. As a result, model discrepancies in climatological Antarctic sea ice area have a significant impact on the intermodel spread of the global LR and WV feedbacks.},
doi = {10.1175/JCLI-D-17-0674.1},
journal = {Journal of Climate},
number = 8,
volume = 31,
place = {United States},
year = {Fri Mar 23 00:00:00 EDT 2018},
month = {Fri Mar 23 00:00:00 EDT 2018}
}
https://doi.org/10.1175/JCLI-D-17-0674.1
Web of Science
Works referencing / citing this record:
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Climatology Explains Intermodel Spread in Tropical Upper Tropospheric Cloud and Relative Humidity Response to Greenhouse Warming
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