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GASS-YoTC Vertical Structure & Physical Processes
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GASS-YoTC : Vertical Structure and Physical Processes of Weather & Climate

A Global Model Evaluation Project*

A Joint Research Activity by the GEWEX Atmosphere System Study (GASS) and WCRP-WWRP/THORPEX Year of Tropical Convection (YOTC) Activity & WGNE MJO Task Force 

To Get Data - contact the "Project Contacts" listed below.

For additional information goto data "Download Guide" link to the left. 

Synopsis: The initial* objective of this project is to characterize, compare and evaluate the heating, moistening and momentum mixing processes associated with the Madden-Julian Oscillation (MJO) that are produced by our global weather and climate models, with a particular focus on their vertical structure. The initial goal is to improve our understanding of the role that convection, cloud, radiative and dynamic processes play in the development and evolution of the MJO in order to achieve better fidelity of the MJO in our global prediction models. The experimental framework takes advantage of the known links between biases seen in short-range forecasts and long-term climate simulations. Making use of the ECMWF YOTC analysis and profiling products from contemporary satellites (e.g. TRMM, CloudSat, Calipso, AIRS), along with a set of systematic and complementary model experiments, this experiment allows characterization, comparison and evaluation of the vertical processes associated with the MJO produced by global models. Three types of simulations have been carried out:

  1. Twenty-year climate simulations that provide a characterization of the models’ intrinsic capabilities at representing MJO variability. Model simulations from both ocean-coupled global models as well as those that use specified SSTs have been contributed. Output includes global information on vertical structure/processes at six-hourly resolution so that adequate information is available for investigating multi-scale interactions.
  2. A series of daily initialized hindcasts for two MJO events within the YOTC period, specifically the two successive MJO events during boreal winter 2009-10 (i.e. YOTC events E and F). A principal focus of this component of the experiment is on providing highly detailed and comprehensive (e.g. every time step) model output over a select near-equatorial Indian Ocean / western Pacific Ocean domain for the initial two days of the hindcasts. This provides the information needed to scrutinize and analyze the detailed evolution of the model MJO as it progresses from a state near the observed one to the model’s intrinsic variability. This hindcast component providse the framework from which one or more analogous cases can be examined from the DYNAMO/CINDY field program that took place in boreal winter 2011-12.
  3. Twenty-day hindcasts of the same events as in (2), over a broader range of initialization dates, with output every three hours over a global or 50N-50S domain.  This component analyses the performance of the model's MJO as a function of forecast lead time, as well as the relationship between the evolution of MJO skill with lead time and the evolution of biases in simulated diabatic processes.  Hindcast components (2) and (3) will provide the framework from which analogous cases can be examined from the DYNAMO/CINDY field program taking place in boreal winter 2011-12.

For all three types of simulations, basic prognostic fields (e.g., temperature, winds, geopotential height), surface fluxes and sub-grid physics tendencies for temperature, moisture and momentum have been archived.  For simulations (1), all fields are global. For simulations (3), all fields are available over at least a 50N-50S latitude, 0-360 longitude domain; many fields are available globally.  For simulation (2), timestep output is available over the Indo-Pacific warm pool region (10S-10N, 60E-180).

Initail analyses of the theree components and a synthesis can be found in Jiang et al. (2015), Xiavier et al. (2015), Klingaman et al. (2105a) and Klingaman et al. (2015b), respectively.

In addition to the overall goal for the project stated above, it is expected that the detailed analysis of physical tendencies of heat, moisture and momentum from the model experiments will be used to define one or more follow-on projects involving process models, as well as to possibly inform needs for future field experiments and observing systems.

Project Sponsors:  GEWEX GASS, WCRP-WCRP/THORPEX YOTC, WGNE MJO Task Force.   See additional Acknowledgments below.    

Project Organizers: Jon Petch & Prince Xavier (UKMO; & lead for component 2), Steve Woolnough and Nicholas Klingaman (U. Reading; & lead for component 3), Duane Waliser and Xianan Jiang (JPL/UCLA; & lead for component 1). 

Project Contacts: Prince Xavier, Nicholas Klingaman, Xianan Jiang

The GASS-YoTC Vertical Structure & Physical Processes Multi-model Experiment was supported
by the World Climate Research Program and World Weather Research Program and organized
by the GEWEX Global Atmospheric System Studies (GASS) subproject and the YoTC/WGNE 
Madden-Julian Oscillation Task Force.  IT support and data services hosted by the NASA Jet Propulsion Laboratory.
Please cite Petch et al. (2011), and/or other relevant studies in References, to refer to the model experiment and dataset.
Support for D. Waliser  was provided by the U.S. National Science Foundation and the NASA Modeling, Analysis and  Prediction (MAP) program.  Support for X. Jiang was provided by the U.S. National Science Foundation and NOAA Climate Program Office (CPO) Modeling, Analysis, Predictions, and Projections (MAPP) Program. Support for N. Klingaman and S. Woolnough was provided by the National Centre for Atmospheric Science, a Natural Environment Research Council collaborative centre.
Jiang, X., D. E. Waliser, P. K. Xavier, J. Petch, N. P. Klingaman, S. J. Woolnough, B. Guan, G. Bellon, T. Crueger, Charlotte DeMott, C. Hannay, H. Lin, W. Hu, D. Kim, C.-L. Lappen, M.-M. Lu, H.-Y. Ma, T. Miyakawa, J. A. Ridout, S. D. Schubert, J. Scinocca, K.-H. Seo, E. Shindo, X. Song, C. Stan, W.-L. Tseng, W. Wang, T. Wu, K. Wyser, X. Wu, G. J. Zhang, and H. Zhu (2015), Vertical Structure and Physical Processes of the Madden-Julian Oscillation: Exploring Key Model Physics in Climate Simulations, Journal of Geophysical Research, 10.1002/2014JD022375.
Klingaman, N. P., S. J. Woolnough, X. Jiang, D. Waliser, P. K. Xavier, J. Petch, M. Caian, C. Hannay, D. Kim, H.-Y. Ma, W. J. Merryfield, T. Miyakawa, M. Pritchard, J. A. Ridout, R. Roehrig, E. Shindo, F. Vitart, H. Wang, N. R. Cavanaugh, B. E. Mapes, A. Shelly, and G. Zhang (2015a), Vertical structure and physical processes of the Madden–Julian Oscillation: Linking hindcast fidelity to simulated diabatic heating and moistening, Journal of Geophysical Research, 10.1002/2014JD022374.

Klingaman, N. P., X. Jiang, P. K. Xavier, J. Petch, D. Waliser, and S. J. Woolnough (2015b), Vertical structure and physical processes of the Madden–Julian oscillation: Synthesis and summary, Journal of Geophysical Research, 10.1002/2015JD023196.
Petch, J., D. Waliser, X. Jiang, P. K. Xavier, and S. Woolnough, 2011: A Global Model Intercomparison of the Physical Processes Associated with the Madden-Julian Oscillation. GEWEX News, August, pp 5.
Xavier, P. K., J. C. Petch, N. P. Klingaman, S. J. Woolnough, X. Jiang, D. E. Waliser, M. Caian, S. M. Hagos, C. Hannay, D. Kim, J. Cole, T. Miyakawa, M. Pritchard, R. Roehrig, E. Shindo, F. Vitart, and H. Wang (2015), Vertical structure and physical processes of the Madden-Julian Oscillation: Biases and uncertainties at short range, Journal of Geophysical Research, 10.1002/2014JD022718.


For more information, please see the project wiki page or the  WCRP/WWRP-Thorpex YOTC web site.

*It is worth stressing that due to the global and extensive nature of the model output, this experimental data set can be utilized for a wide variety of other weather and climate phenomena and we encourage its use for such purposes.


Last Update: Sept. 14, 2016, 6:47 p.m. by Duane Waliser
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