Max Planck Institute for Meteorology, Germany
Edwin P. Gerber
New York University, USA
Coordinators: Elisa Manzini and Edwin Gerber
Committee Members: Amy Butler, Natalia Calvo, Andrew Charlton-Perez, Marco Giorgetta, Adam Scaife, Tiffany Shaw and Shingo Watanabe
Ex-Officio Members: Judith Perlwitz, Lorenzo Polvani and Fabrizio Sassi
DynVar is an international working group on the modelling of the dynamics and variability of the stratosphere-troposphere system. DynVar focuses on the interactions between atmospheric variability, dynamics, and climate change, with a particular emphasis on the two-way coupling between the troposphere and stratosphere. To this end, DynVar promotes the development and use of coupled atmosphere-ocean-sea-ice general circulation models, with the atmospheric component extending to above the stratopause.
The key questions addressed by the activity are:
- How do dynamical processes contribute to persistent model biases in the mean state and variability of the atmosphere, including biases in the position, strength, and statistics of blocking events, storm tracks, and the stratospheric polar vortex?
- How does the stratosphere affect climate variability at intra-seasonal, inter-annual, and decadal time scales?
- What is the role of dynamics in shaping the climate response to anthropogenic forcings (e.g. global warming, ozone depletion) and how do dynamical processes contribute to uncertainty in future climate projections?
DynVar has been active in the assessment of stratospheric mean climate, variability, and change, as well as of the stratosphere-troposphere dynamical coupling in climate models participating in the latest set of climate projections, carried out under the fifth Coupled Model Inter-comparison Project (CMIP5). On discerning the role of the stratosphere on intraseasonal time scales, initiatives within DynVar have focused on the stratospheric seasonal prediction hindcasts produced as part of WGSIP’s Stratosphere Historical Forecast Project (SHFP).
The use of simplified models and more theoretical approaches to build the knowledge of two-way stratosphere-troposphere coupling is also an important component of the activity. DynVar is also extending its focus to tropospheric dynamics, storm tracks, jets, blocking, and their modes of variability, with the aim of reaching a comprehensive understanding of troposphere-stratosphere variability and change. These DynVar activities connect most closely to the WCRP Grand Challenge on Clouds, Circulation, and Climate Sensitivity.
DynVar organises community workshops approximately every 3 years. The next workshop is being held in June 2016 in Helsinki, Finland.
- Intra-seasonal variability, including sudden stratospheric warming; extratropical wave coupling, annular modes, blocking and storm tracks
- Troposphere-stratosphere circulation changes
- ENSO, MJO and QBO interactions, tropical and extra-tropical
Gerber, E. P. and E. Manzini, 2016: The Dynamics and Variability Model Intercomparison Project (DynVarMIP) for CMIP6: assessing the stratosphere–troposphere system. Geosci. Model Dev., 9, 3413-3425
Kidston J., A. A.Scaife, Steven C. Hardiman, Daniel M. Mitchell, Neal Butchart, Mark P. Baldwin and Lesley J. Gray, 2015: Stratospheric influence on tropospheric jet streams, storm tracks and surface weather. Nat. Geosci., 8, 433-450
Barnes, E.A., N.W. Barnes and L.M. Polvani, 2014: Delayed Southern Hemisphere climate change induced by stratospheric ozone recovery, as projected by the CMIP5 models. J. Climate, 27, 852-867.
Gerber, E. P. and S.-W. Son, 2014: Quantifying the Summertime Response of the Austral Jet Stream and Hadley Cell to Stratospheric Ozone and Greenhouse Gases. J. Climate, 27, 5538-5559, doi: 10.1175/JCLI-D-13-00539.1
Lott, F. et al., 2014: Kelvin and Rossby-gravity wave packets in the lower stratosphere of some high-top CMIP5 models. JGR Atmos., 119, 2156–2173, doi: 10.1002/2013JD020797
Manzini, E. et al., 2014: Northern winter climate change: Assessment of uncertainty in CMIP5 projections related to stratosphere-troposphere coupling. JGR Atmos., 119, doi: 10.1002/2013JD021403
Neely, R.R., D.R. Marsh, K.L. Smith, S.M. Davis and L.M. Polvani, 2014: Biases in Southern Hemisphere climate trends induced by coarsely specifying the temporal resolution of stratospheric ozone. Geophys. Res. Lett., 41, doi:10.1002/2014GL061627
Scaife, A. A., et al., 2014: Predictability of the quasi-biennial oscillation and its northern winter teleconnection on sea- sonal to decadal timescales. Geophys. Res. Lett., 41, 1752–1758, doi:10.1002/ 2013GL059160.
Seviour W.J.M., S.C. Hardiman, L.J. Gray, N. Butchart, C. MacLachlan and A.A. Scaife, 2014: Skillful seasonal prediction of the Southern Annular Mode and Antarctic ozone. J. Clim., 27, 7462-7474, DOI: 10.1175/JCLI-D-14-00264.1.
Shaw, T. A., J. Perlwitz, O. Weiner, 2014: Troposphere-stratosphere coupling: Links to North Atlantic weather and climate, including their representation in CMIP5 models. J. Geophys. Res., 10.1002/2013JD021191
Simpson, I.R., T.A. Shaw, and R. Seager, 2014: A Diagnosis of the Seasonally and Longitudinally Varying Midlatitude Circulation Response to Global Warming. J. Atmos. Sci., 71, 2489-2514, DOI: 10.1175/JAS-D-13-0325.1
Kawatani, Y., and K. Hamilton, 2013: Weakened stratospheric quasibiennial oscillation driven by increased tropical mean upwelling. Nature, 497, doi:10.1038/nature12140 See also corrigendum.
Hardiman, S.C., N. Butchart, and N. Calvo, 2013: The morphology of the Brewer–Dobson circulation and its response to climate change in CMIP5 simulations. Q.J.R. Meteorol. Soc., DOI: 10.1002/qj.2258
Charlton-Perez, A. J., M. Baldwin, T. Birner, R.X. Black, A.H. Butler, N. Calvo, N.A. Davis, E.P. Gerber, N. Gillett, S. Hardiman, J. Kim, K. Krüger, Y.-Y. Lee, E. Manzini, B.A. McDaniel, L. Polvani, T. Reichler, T.A. Shaw, M. Sigmond, S.-W. Son, M. Toohey, L. Wilcox, S. Yoden, B. Christiansen, F. Lott, D. Shindell, S. Yukimoto, S. Watanabe, 2013: On the lack of stratospheric dynamical variability in low-top versions of the CMIP5 models. J. Geophys. Res. Atmos., 118, 2494–2505, doi:10.1002/jgrd.50125
Reichler, T., J. Kim, E. Manzini, and J. Kröger, 2012: A stratospheric connection to Atlantic climate variability. Nature Geoscience, Letters, 5, 783-787. DOI 10.1038/ngeo1586.
Gerber, E.P., A. Butler, N. Calvo, A. Charlton-Perez, M. Giorgetta, E. Manzini, J. Perlwitz, L. M. Polvani, F. Sassi, A.A. Scaife, T. A. Shaw, S.-W. Son, S. Watanabe, 2012: Assessing and Understanding the Impact of Stratospheric Dynamics and Variability on the Earth System. Bulletin of the American Meteorological Society 93: 845-859.
SPARC activity updates:
SPARC Newsletter No. 41, 2013, p. 40: Report on the 3rd SPARC DynVar Workshop on Modelling the Dynamics and Variability of the Stratosphere-Troposphere System, by E. Manzini et al.
SPARC Newsletter No. 36, 2011, p. 19: Report on the SPARC DynVar Workshop 2 on Modelling the Dynamics and Variability of the Stratosphere-Troposphere System, by E. Manzini et al.
SPARC Newsletter No. 32, 2009, p. 13: SPARC Dynamics and Variability Project (DynVar): Plans and Status, by P.J. Kushner et al.
SPARC Newsletter No. 29, 2007, p. 9: The SPARC DynVar Project: A SPARC Project on the Dynamics and Variability of the Coupled Stratosphere-Troposphere System, by P.J. Kushner et al.