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Multimodel assessment of the upper troposphere and lower stratosphere: Tropics and global trends

Gettelman, Andrew and Hegglin, Michaela and Son, S.-W. and Kim, J. and Fujiwara, M. and Birner, T. and Kremser, S. and Rex, M. and Añel, A.J. and Akiyoshi, H. and Austin, J. and Bekki, S. and Braesicke, P. and Brühl, C. and Butchart, N. and Chipperfield, M. and Dameris, M. and Dhomse, S. and Garny, H. and Hardiman, S.C. and Jöckel, P. and Kinnison, D.E. and Lamarque, J.F. and Mancini, E. and Marchand, M. and Michou, M. and Morgenstern, O. and Pawson, S. and Pitari, G. and Plummer, D.A. and Pyle, J.A. and Rozanov, E. and Scinocca, J.F. and Shepherd, T.G. and Shibata, K. and Smale, D. and Teyssèdre, H. and Tian, W. (2010) Multimodel assessment of the upper troposphere and lower stratosphere: Tropics and global trends. Journal of Geophysical Research, 115 (D00M08), pp. 1-22. DOI: 10.1029/2009JD013638.

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Official URL: http://www.agu.org/journals/jd/jd1020/2009JD013638/2009JD013638.pdf

Abstract

The performance of 18 coupled Chemistry Climate Models (CCMs) in the Tropical Tropopause Layer (TTL) is evaluated using qualitative and quantitative diagnostics. Trends in tropopause quantities in the tropics and the extratropical Upper Troposphere and Lower Stratosphere (UTLS) are analyzed. A quantitative grading methodology for evaluating CCMs is extended to include variability and used to develop four different grades for tropical tropopause temperature and pressure, water vapor and ozone. Four of the 18 models and the multi�model mean meet quantitative and qualitative standards for reproducing key processes in the TTL. Several diagnostics are performed on a subset of the models analyzing the Tropopause Inversion Layer (TIL), Lagrangian cold point and TTL transit time. Historical decreases in tropical tropopause pressure and decreases in water vapor are simulated, lending confidence to future projections. The models simulate continued decreases in tropopause pressure in the 21st century, along with �1K increases per century in cold point tropopause temperature and 0.5�1 ppmv per century increases in water vapor above the tropical tropopause. TTL water vapor increases below the cold point. In two models, these trends are associated with 35% increases in TTL cloud fraction. These changes indicate significant perturbations to TTL processes, specifically to deep convective heating and humidity transport. Ozone in the extratropical lowermost stratosphere has significant and hemispheric asymmetric trends. O3 is projected to increase by nearly 30% due to ozone recovery in the Southern Hemisphere (SH) and due to enhancements in the stratospheric circulation. These UTLS ozone trends may have significant effects in the TTL and the troposphere.

Document Type:Article
Title:Multimodel assessment of the upper troposphere and lower stratosphere: Tropics and global trends
Authors:
AuthorsInstitution or Email of Authors
Gettelman, AndrewNCAR, Boulder, CO, USA
Hegglin, MichaelaUni Toronto, Toronto, Ontario, CND
Son, S.-W.McGill Univ., Montreal, Quebec, CND
Kim, J.McGill Univ., Montreal, Quebec, CND
Fujiwara, M.Hokkaido Univ., Sapporo, J
Birner, T.Colorado State Univ., Fort Collins, CO, USA
Kremser, S.FU Berlin
Rex, M.AWI Potsdam
Añel, A.J.UNSPECIFIED
Akiyoshi, H.UNSPECIFIED
Austin, J.UNSPECIFIED
Bekki, S.UNSPECIFIED
Braesicke, P.UNSPECIFIED
Brühl, C.UNSPECIFIED
Butchart, N.UNSPECIFIED
Chipperfield, M.UNSPECIFIED
Dameris, M.DLR-PA
Dhomse, S.UNSPECIFIED
Garny, H.DLR-PA
Hardiman, S.C.UNSPECIFIED
Jöckel, P.UNSPECIFIED
Kinnison, D.E.UNSPECIFIED
Lamarque, J.F.UNSPECIFIED
Mancini, E.UNSPECIFIED
Marchand, M.UNSPECIFIED
Michou, M.UNSPECIFIED
Morgenstern, O.UNSPECIFIED
Pawson, S.UNSPECIFIED
Pitari, G.UNSPECIFIED
Plummer, D.A.UNSPECIFIED
Pyle, J.A.UNSPECIFIED
Rozanov, E.UNSPECIFIED
Scinocca, J.F.UNSPECIFIED
Shepherd, T.G.UNSPECIFIED
Shibata, K.UNSPECIFIED
Smale, D.UNSPECIFIED
Teyssèdre, H.UNSPECIFIED
Tian, W.UNSPECIFIED
Date:2010
Journal or Publication Title:Journal of Geophysical Research
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:115
DOI:10.1029/2009JD013638
Page Range:pp. 1-22
Status:Published
Keywords:TTL, chemistry-climate models, CCMVal
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: Jana Freund
Deposited On:27 Oct 2010 17:19
Last Modified:23 Jan 2014 11:36

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