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The influence of external forcing on subdecadal variability of regional surface temperature in CMIP5 simulations of the last millennium

Le, Thanh LU ; Sjolte, Jesper LU and Muscheler, Raimund LU (2016) In Journal of Geophysical Research: Atmospheres 121(4). p.1671-1682
Abstract
We use Granger causality to investigate the influences of external forcings on subdecadal variability of regional near-surface air temperature (SAT) in past millennium simulations (period 850–1850 A.D.) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Our results strengthen the conclusion for robust influence of volcanic forcing on SAT during preindustrial times of the last millennium. The SAT response to solar variations is detected in tropical and subtropical regions. In other regions, this response is weak. The impact of greenhouse gases (GHGs) radiative forcing to regional SAT is weak and uncertain. This is most probably due to the low amplitude of the variations in GHGs and hence weak GHGs forcing during the... (More)
We use Granger causality to investigate the influences of external forcings on subdecadal variability of regional near-surface air temperature (SAT) in past millennium simulations (period 850–1850 A.D.) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Our results strengthen the conclusion for robust influence of volcanic forcing on SAT during preindustrial times of the last millennium. The SAT response to solar variations is detected in tropical and subtropical regions. In other regions, this response is weak. The impact of greenhouse gases (GHGs) radiative forcing to regional SAT is weak and uncertain. This is most probably due to the low amplitude of the variations in GHGs and hence weak GHGs forcing during the preindustrial millennium. The low agreement between models in simulating the impacts of solar variations on SAT in several regions suggests the different dynamical responses in these models, possibly associated with inaccurate parameterization of the processes related to solar forcing. Our analysis suggests that internal climate variability played a more significant role than external forcings in short-term SAT variability in the regions of the North Atlantic, the North Pacific, the Arctic, the Antarctic Peninsula, and its surrounding oceans. The possibility of long-term impacts of external forcings on SAT and the uncertainties that might be contained due to effects of internal climate modes other than El Niño–Southern Oscillation underscore the necessity for a more detailed understanding of the dynamical response of SAT to external forcings. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Journal of Geophysical Research: Atmospheres
volume
121
issue
4
pages
1671 - 1682
publisher
Wiley-Blackwell
external identifiers
  • scopus:84959450224
  • wos:000372977900019
ISSN
2169-8996
DOI
10.1002/2015JD024423
language
English
LU publication?
yes
id
7520cfe8-fbbc-4584-963d-fd188de15b24
date added to LUP
2016-06-19 15:16:15
date last changed
2017-01-01 08:28:28
@article{7520cfe8-fbbc-4584-963d-fd188de15b24,
  abstract     = {We use Granger causality to investigate the influences of external forcings on subdecadal variability of regional near-surface air temperature (SAT) in past millennium simulations (period 850–1850 A.D.) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Our results strengthen the conclusion for robust influence of volcanic forcing on SAT during preindustrial times of the last millennium. The SAT response to solar variations is detected in tropical and subtropical regions. In other regions, this response is weak. The impact of greenhouse gases (GHGs) radiative forcing to regional SAT is weak and uncertain. This is most probably due to the low amplitude of the variations in GHGs and hence weak GHGs forcing during the preindustrial millennium. The low agreement between models in simulating the impacts of solar variations on SAT in several regions suggests the different dynamical responses in these models, possibly associated with inaccurate parameterization of the processes related to solar forcing. Our analysis suggests that internal climate variability played a more significant role than external forcings in short-term SAT variability in the regions of the North Atlantic, the North Pacific, the Arctic, the Antarctic Peninsula, and its surrounding oceans. The possibility of long-term impacts of external forcings on SAT and the uncertainties that might be contained due to effects of internal climate modes other than El Niño–Southern Oscillation underscore the necessity for a more detailed understanding of the dynamical response of SAT to external forcings.},
  author       = {Le, Thanh and Sjolte, Jesper and Muscheler, Raimund},
  issn         = {2169-8996},
  language     = {eng},
  month        = {02},
  number       = {4},
  pages        = {1671--1682},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of Geophysical Research: Atmospheres},
  title        = {The influence of external forcing on subdecadal variability of regional surface temperature in CMIP5 simulations of the last millennium},
  url          = {http://dx.doi.org/10.1002/2015JD024423},
  volume       = {121},
  year         = {2016},
}