Gravity waves

Activity leaders

Joan Alexander
NWRA, Colorado Research Associates Division (CoRA), USA
moc.a1552949274rwn.a1552949274roc@d1552949274naxel1552949274a1552949274

Kaoru Sato
University of Tokyo, Earth and Planetary Science, Japan
pj.ca1552949274.oyko1552949274t-u.s1552949274.spe@1552949274uroak1552949274

Fuqing Zhang
Penn State University, Center for Advanced Data Assimilation and Predictability Techniques, USA
ude.u1552949274sp@gn1552949274ahzf1552949274

Overview

The SPARC Gravity Wave Activity in recent years has placed a focus on the role of gravity waves in driving the general circulation of the stratosphere. While planetary-scale Rossby wave-driving clearly dominates the stratospheric circulation, small biases in the zonal-mean zonal winds can have very signifcant effects on Rossby wave propagation. Parameterized gravity wave (GW) drag in climate models is a primary tool used to reduce zonal-mean wind biases, and hence small-scale GWs can have larger impacts by helping to shape the propagation pathways of the more dominant Rossby waves.  In the tropical stratosphere, GWs also play a dominant role in driving the quasi-biennial oscillation. This gives small-scale GWs an important role in regional climate patterns by shaping teleconnection pathways.

GWs have additional roles in long-range weather forecasting through their influence on planetary wave propagation and sudden stratospheric warmings.  Improving the realism of these processes in global models requires realistic GW drag forces and their changes over the broad range of timescales for weather and climate applications.

Current high resolution global models can resolve GWs, at least partly. In relation to this, new issues regarding high resolution global models have emerged. Scale-aware parameterizations are needed, those that scale down parameterized GW forces as resolution improves, in order to avoid double counting the GW effect. However, resolvability of GWs and GW drag in models with different dynamical cores (e.g. spectral models versus grid models) is itself a complex and interesting issue and another area of active research.

Current activities

A new project called New Quantitative Constraints on Orographic Gravity Wave Stress and Drag: Satisfying Emerging Needs in Seasonal-to-Subseasonal and Climate Prediction was launched in summer of 2018.  The project was selected for funding as an International Team by the International Space Science Institute.  Further information about this project can be found at http://www.issibern.ch/teams/consonorogravity/

 

gravity Wave event seen from satellite
High-resolution 3D satellite retrieval of an Andean OGW event in the stratosphere (left) and analysis of the vector momentum flux (“MF”) or stress (center & right). [Wright et al. 2017]

Future plans

The 5th quinquennial SPARC Gravity Wave Symposium will be held 27 September—1 October 2021 in Frankfurt, Germany.  The meeting will be co-hosted by the MS-GWaves Project, with local organization led by Professor Ulrich Achatz of Goethe-Universitaet Frankfurt.  Meeting participants will be invited to submit manuscripts to a special AMS Collection on Multi-Scale Dynamics of Gravity Waves.  Watch this page for further announcements in advance of the meeting.

Published results

Journal publications:

de la Cámara, A. and F. Lott, 2015: A parameterization of gravity waves emitted by fronts and jets. Geophys. Res. Lett., 42, doi:10.1002/2015GL063298.

Plougonven, R., A. Hertzog, and M. J. Alexander, 2015: Case studies of nonorographic gravity waves over the Southern Ocean emphasize the role of moisture. J. Geophys. Res., 120, 1278-1299.

Sato, K. and M. Nomoto, 2015: Gravity wave-induced anomalous potential vorticity gradient generating planetary waves in the winter mesosphere. J. Atmos. Sci., 72, 3609-3624. doi: dx.doi.org/10.1175/JAS-D-15‐0046.1

Scheffler, G., and M. Pulido, 2015: Compensation between resolved and unresolved wave drag in the stratospheric final warnings of the Southern Hemisphere. J. Atmos. Sci., 72, doi: dx.doi.org/10.1175/JAS‐D-14‐0270.1

Geller, M.A., M.J. Alexander, P.T. Love, J. Bacmeister, M. Ern, A. Hertzog, E. Manzini, P. Preusse, K. Sato, A.A. Scaife and T. Zhou, 2013: A Comparison between Gravity Wave Momentum Fluxes in Observations and Climate Models. J. Climate, 26, No. 17, 6383-6405

Alexander, M. J., M. Geller, C. McLandress, S. Polavarapu, P. Preusse, F. Sassi, K. Sato, S. Eckermann, M. Ern, A. Hertzog, Y. Kawatani, M. Pulido, T. Shaw, M. Sigmond, R. Vincent, and S. Watanabe, 2010: Recent Developments on Gravity Wave Effects in Climate Models, and the Global Distribution of Gravity Wave Momentum Flux from Observations and Models. Q. J. Roy. Meteorol. Soc., 136, 1103-1124

SPARC activity updates:

SPARC Newsletter No. 48, 2017, pp 22-25: Report on the SPARC Gravity Wave Symposium, May 16-20, Pennsylvania State University, United States, Zhang, F., M. J. Alexander, and K. Sato.

SPARC Newsletter No. 44, 2015, p. 9: Gravity Wave Dynamics and Climate: An Update from the SPARC Gravity Wave Activity, M. Joan Alexander and Kaoru Sato.

SPARC Newsletter No. 37, 2011, p. 18: Report on the Chapman Conference on Atmospheric Gravity Waves and Their Effects on General Circulation and Climate, M. Joan Alexander, Kevin Hamilton, and Kaoru Sato.

SPARC Newsletter No. 35, 2010, p. 17: A report on the SPARC Gravity Wave Activity, M. Joan Alexander.

SPARC Newsletter No. 31, 2008, p. 6: New SPARC Project: Gravity Wave Momentum Budget for Global Circulation Studies, M. Joan Alexander.

SPARC Newsletter No. 28, 2007, p. 26: Report on the Gravity Wave Retreat, 26 June – 7 July 2006, Boulder, Colorado, USA, J. H. Richter, M. A. Geller, R. R. Garcia, H.-L. Liu, F. Zhang.

Meetings

2016 SPARC Gravity Wave Symposium
16-20 May 2016
The Atherton Hotel and Pennsylvania State University, State College, Pennsylvania, USA.

Website for further information

http://www.issibern.ch/teams/consonorogravity/