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Impact of stratospheric variability on tropospheric climate change

Dall'Amico, Mauro and Stott, Peter A. and Scaife, Adam A. and Gray, Lesley J. and Rosenlof, Karen H. and Karpechko, Alexey Yu. (2010) Impact of stratospheric variability on tropospheric climate change. Climate Dynamics, 34, pp. 399-417. Springer. DOI: 10.1007/s00382-009-0580-1.

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Official URL: http://www.springerlink.com/content/nw420867510ht627/fulltext.pdf


An improved stratospheric representation has been included in simulations with the Hadley Centre HadGEM1 coupled ocean atmosphere model with natural and anthropogenic forcings for the period 1979–2003. An improved stratospheric ozone dataset is employed that includes natural variations in ozone as well as the usual anthropogenic trends. In addition, in a second set of simulations the quasi biennial oscillation (QBO) of stratospheric equatorial zonal wind is also imposed using a relaxation towards ERA-40 zonal wind values. The resulting impact on tropospheric variability and trends is described. We show that the modelled cooling rate at the tropopause is enhanced by the improved ozone dataset and this improvement is even more marked when the QBO is also included. The same applies to warming trends in the upper tropical troposphere which are slightly reduced. Our stratospheric improvements produce a significant increase of internal variability but no change in the positive trend of annual mean global mean near-surface temperature. Warming rates are increased significantly over a large portion of the Arctic Ocean. The improved stratospheric representation, especially the QBO relaxation, causes a substantial reduction in near-surface temperature and precipitation response to the El Chichón eruption, especially in the tropical region. The winter increase in the phase of the northern annular mode observed in the aftermath of the two major recent volcanic eruptions is partly captured, especially after the El Chichón eruption. The positive trend in the southern annular mode (SAM) is increased and becomes statistically significant which demonstrates that the observed increase in the SAM is largely subject to internal variability in the stratosphere. The possible inclusion in simulations for future assessments of full ozone chemistry and a gravity wave scheme to internally generate a QBO is discussed.

Document Type:Article
Title:Impact of stratospheric variability on tropospheric climate change
AuthorsInstitution or Email of Authors
Dall'Amico, MauroMauro.DallAmico@dlr.de
Rosenlof, Karen H.UNSPECIFIED
Karpechko, Alexey Yu.UNSPECIFIED
Journal or Publication Title:Climate Dynamics
Refereed publication:Yes
In Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 399-417
Keywords:Simulations of recent climate with natural and anthropogenic forcings assessed by the IPCC 2007 AR4 - Observed ozone distributions - Quasi-biennial oscillation (QBO) of stratospheric equatorial zonal wind - Variability and trends at the tropopause and in the troposphere - Response to the volcanic eruptions of El Chichón and Mt. Pinatubo
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EO - Erdbeobachtung
DLR - Research area:Space
DLR - Program:W EO - Erdbeobachtung
DLR - Research theme (Project):W - Vorhaben Atmosphären- und Klimaforschung (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Atmospheric Dynamics
Deposited By: Mauro Dall Amico
Deposited On:05 Aug 2009 12:16
Last Modified:12 Dec 2013 20:41

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