TITLE

Planetary Waves, Cyclogenesis, and the Irregular Breakdown of Zonal Motion over the North Atlantic

AUTHOR(S)
Roebber, Paul J.
PUB. DATE
November 2009
SOURCE
Monthly Weather Review;Nov2009, Vol. 137 Issue 11, p3907
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Numerous observational and modeling studies have suggested the importance of cyclogenesis to the breakdown of the zonal flow and the maintenance of atmospheric blocks, whereas other studies have shown that low-frequency dynamics are sufficient to produce and maintain these patterns. Experiments with a simple model of the general circulation and empirical evidence obtained from reanalysis and cyclone tracking data are used to develop a conceptual understanding of this irregular response. The model’s results and observational data are consistent with the idea that the North Atlantic flow response to cyclone forcing is preconditioned by the state of the hemispheric circulation. A characteristic hemispheric flow configuration reminiscent of the shedding of a potential vorticity (PV) filament and tightening of the PV gradient is particularly responsive to cyclogenesis, with the likelihood of below 10th percentile North Atlantic zonal flow under these conditions increased by a factor of 2.37 for each cyclone event. A second characteristic pattern, reminiscent of the PV wave-breaking anticyclonic roll up, responds in an opposite way to cyclogenesis, with a decrease in the likelihood of below 10th percentile zonal flow by a factor of 0.67. This perspective is connected to the decades of research on blocking and opens an opportunity for the development of medium-range forecast model postprocessors that might provide probabilistic forecasts of North Atlantic flow transitions.
ACCESSION #
45301996

 

Related Articles

  • Forced Disturbances in a Zero Absolute Vorticity Gradient Environment. Choboter, Paul F.; Brunet, Gilbert // Journal of the Atmospheric Sciences;5/1/2000, Vol. 57 Issue 9, p1406 

    Presents information on a study which investigated the effect of forcing on the evolution of Rossby waves in a zero potential vorticity gradient environment. Advantages of using isentropic potential vorticity in describing the dynamics of the atmosphere; Numerical methods; Results and...

  • Interpreting the Opposition between Two Block-Onset Forcing Mechanisms. Li Dong; Colucci, Stephen J. // Journal of the Atmospheric Sciences;Jun2007, Vol. 64 Issue 6, p2091 

    The opposition between two block-onset forcing mechanisms, previously identified in midtropospheric analyses over the Southern Hemisphere midlatitudes, is analytically interpreted with an idealized model. These mechanisms are the interaction (Finter) between deformation and potential vorticity...

  • The Role of Rossby Wave Breaking in Shaping the Equilibrium Atmospheric Circulation Response to North Atlantic Boundary Forcing. STRONG, COURTENAY; MAGNUSDOTTIR, GUDRUN // Journal of Climate;Mar2010, Vol. 23 Issue 6, p1269 

    The role of Rossby wave breaking (RWB) is explored in the transient response of an atmospheric general circulation model to boundary forcing by sea ice anomalies related to the North Atlantic Oscillation (NAO). When the NCAR Community Climate Model, version 3, was forced by an exaggerated sea...

  • How Large-Scale and Cyclogeostrophic Barotropic Instabilities Favor the Formation of Anticyclonic Vortices in the Ocean. Perret, Gaëële; Dubos, Thomas; Stegner, Alexandre // Journal of Physical Oceanography;Feb2011, Vol. 41 Issue 2, p303 

    Large-scale vortices, that is, eddies whose characteristic length scale is larger than the local Rossby radius of deformation Rd, are ubiquitous in the oceans, with anticyclonic vortices more prevalent than cyclonic ones. Stability or robustness properties of already formed shallow-water...

  • Vortices and Rossby waves in cylinder wakes on a parabolic β-plane observed by altimetric imaging velocimetry. Afanasyev, Y. D.; Rhines, P. B.; Lindahl, E. G. // Physics of Fluids;Aug2008, Vol. 20 Issue 8, p086604 

    Intense vortices in the wake of a circular cylinder are investigated in a rotating parabolic (polar) β-plane fluid. This system has a background potential vorticity (PV) field that supports Rossby waves and causes vortices to migrate and radiate. A method for imaging rotating flows, which we...

  • Planetary Wave Breaking and Tropospheric Forcing as Seen in the Stratospheric Sudden Warming of 2006. Coy, Lawrence; Eckermann, Stephen; Hoppel, Karl // Journal of the Atmospheric Sciences;Feb2009, Vol. 66 Issue 2, p495 

    The major stratospheric sudden warming (SSW) of January 2006 is examined using meteorological fields from Goddard Earth Observing System version 4 (GEOS-4) analyses and forecast fields from the Navy Operational Global Atmospheric Prediction System–Advanced Level Physics, High Altitude...

  • Nonlinear interaction of small-scale Rossby waves with an intense large-scale zonal flow. Manin, Dmitrii Yu.; Nazarenko, Sergey V. // Physics of Fluids;Mar1994, Vol. 6 Issue 3, p1158 

    The system of Rossby waves is unstable with respect to modulations. This instability results in the generation of a large-scale zonal flow with zero mean vorticity. It is shown that in both stable and unstable situations, a finite-time singularity formation takes place in the system. Such a...

  • Diminutive Frontal Waves—A Link between Fronts and Cyclones. Hewson, Tim D. // Journal of the Atmospheric Sciences;Jan2009, Vol. 66 Issue 1, p116 

    A number of recent publications have dealt with cyclone identification and tracking. Following on, this paper extends the typical cyclone life cycle back in time to embrace a new feature called a “diminutive frontal wave.” One aim is to improve predictability by extending tracks....

  • Centrifugal-Dissipative Instability of Rossby Vortices and Their Cyclonic–Anticyclonic Asymmetry. Chefranov, S. G. // JETP Letters;3/25/2001, Vol. 73 Issue 6, p274 

    A new linear centrifugal-dissipative mechanism is proposed that explains the vortex asymmetry observed, in particular, in the structure of low-frequency anticyclonic Rossby vortices. It is shown that the relevant centrifugal-dissipative instability, which spontaneously breaks the chiral symmetry...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics