Global Synoptic Dynamic Model (GSDM)

Here are the current Papers & Articles under the research topic Global Synoptic Dynamic Model (GSDM). Click on the title of a paper you are interested in to go straight to the full paper.

What is the GSDM and how does it help with subseasonal weather forecasts?
A YouTube Presentation by leading meteorologist Ed Berry at the American Meteorology Society - Student Chapter,  College of DuPage, on 28th March 2018.
Outline:
Leading meteorological scientists Ed Berry and Dr Klaus Weickmann jointly developed their GSDM (Global Synoptic Dynamic Model) while they were working at NOAA in the late 1990s and early 2000s. They also devised the GWO (Global Wind Oscillation) as a way of plotting and measuring the amounts of relative global AAM (Atmospheric Angular Momentum), frictional torque and mountain torque at different phases of the cycle. They became leaders in this specialist area which has been used to assist in understanding global weather patterns and upcoming changes up to a few weeks ahead. Regretfully they retired from NOAA several years ago and weren't replaced. Klaus Weickmann has fully retired from all activity but Ed Berry continues his excellent work and in 2018 he gave this excellent presentation to the AMS. This is a one hour seminar with clear charts and explanations, ending with a Q&A session.

Global Synoptic Dynamic Model (GSDM)
NOAA publication - an overview written by Weickmann and Berry, 2008.
No abstract. Discusses the Global Wind Oscillation (GWO), Atmospheric Angular Momentum (AAM), including GWO Phases and interaction with the MJO.

A Synoptic–Dynamic Model of Subseasonal Atmospheric Variability
Published Feb 2007 by Klaus Weickmann and Edward Berry
Abstract:
A global synoptic–dynamic model (GSDM) of subseasonal variability is proposed to provide a framework for real-time weather–climate monitoring and to assist with the preparation of medium-range (e.g., week 1–3) predictions. The GSDM is used with a regional focus over North America during northern winter. A case study introduces the time scales of the GSDM and illustrates two circulation transitions related to eastward-moving wave energy signals and their connection to remote tropical forcing. Global and zonal atmospheric angular momentum (AAM) is used to help define the synoptic evolution of the GSDM components and to link regional synoptic variations with physical processes like the global mountain and frictional torque. The core of the GSDM consists of four stages based on the Madden–Julian oscillation (MJO) recurrence time. Additionally, extratropical behaviors including teleconnection patterns, baroclinic life cycles, and ∼monthly oscillations provide intermediate and fast time scales that are combined with the quasi-oscillatory (30–70 day) MJO to define multiple time-/space-scale linear relationships. A unique feature of the GSDM is its focus on global and regional circulation transitions and the related extreme weather events during periods of large global AAM tendency.

The tropical Madden-Julian Oscillation and the Global Wind Oscillation
Published June 2008 by Klaus Weickmann; Edward Berry
Abstract:
The global wind oscillation (GWO) is a subseasonal phenomenon encompassing the Madden-Julian Oscillation (MJO) and mid-latitude processes like meridional momentum transports and mountain torques. A phase space is defined for the GWO following the approach of Wheeler and Hendon (2004) for the MJO. In contrast to the oscillatory behavior of the MJO, two red noise processes define the GWO. The red noise spectra have variance at periods that bracket the 30-60 day band generally used to define the MJO. The MJO and GWO correlation accounts for 25% of their variance and cross-spectra show well-defined phase relations. However, considerable independent variance still exists in the GWO. During MJO and GWO episodes, key events in the circulation and tropical convection derived from composites can be used for monitoring and for evaluating prediction model forecasts, especially for weeks 1-3. A case study during April-May 2007 focuses on the GWO and two ~30 day duration orbits with extreme anomalies in GWO phase space. The MJO phase space projections for the same time were partially driven by mountain torques and meridional transports. The case reveals the tropical-extratropical character of subseasonal events and its role in creating slowly evolving planetary-scale circulation and tropical convection anomalies.