Baroclinic wave packets in models and observations

Journal Article · Sat May 15 04:00:00 EDT 1993 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1993)050<1413:BWPIMA>2.0.CO;2· OSTI ID:6296632

Lee, S; Held, I M ^[1]

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1. Princeton Univ., NJ (United States)

Coherent baroclinic wave packets are present in the Southern Hemisphere, most clearly in the summer season. These coherent packets are also found in a hierarchy of models of nonlinear baroclinic instability-a two-layer quasigeostrophic (QG) model on a [beta]-plane, a two-level primitive equation (PE) model, and a general circulation model. The flows are chaotic, but the packet itself can remain remarkably coherent, despite the complex evolution of the flow within the packet. In both QG and PE models, the packets become more robust as the supercriticality of the flow is reduced. In both models and the observations, the packets move with a group velocity that is greater than the phase speed of the individual disturbances, so that these disturbances exhibit downstream development. The structure of the baroclinic waves in the packet as a function of longitude resembles the life cycles of sinusoidal baroclinic waves as a function of time. More than one packet can exist in the domain at the same time. In the QG model, the number of packets increased in a systematic way as the length of the channel increases. 28 refs., 16 figs., 1 tab.

• OSTI ID: 6296632
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 50:10; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC CIRCULATION
COMPARATIVE EVALUATIONS
DISTURBANCES
EARTH ATMOSPHERE
EARTH PLANET
EVALUATION
GENERAL CIRCULATION MODELS
MATHEMATICAL MODELS
METEOROLOGY
NONLINEAR PROBLEMS
PLANETS
SOUTHERN HEMISPHERE
SYNTHESIS
WAVE PACKETS