Mechanisms of low-frequency variability in a simple model with orography

Journal Article · Mon Mar 15 04:00:00 EST 1993 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1993)050<0878:MOLFVI>2.0.CO;2· OSTI ID:6438375

Robinson, W A ^[1]

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1. Univ. of Illinois, Urbana (United States)

Mechanisms of low-frequency variability are examined in an extended run of a two-level nonlinear global model with a single isolated mountain. The presence of the mountain modifies the low-frequency behavior, compared with that in a zonally homogeneous model, in two ways. First, slow variations in the zonally averaged circulation, the zonal index, are manifest as variability in the train of stationary waves generated by the orography. Second, trains of low-frequency Rossby waves are modified by their propagation through the model's zonally asymmetric time-mean flow. These eddies become meridionally elongated at the jet entrance and zonally elongated at its exit, allowing them to extract energy barotropically from the mean flow in the jet exit.

• OSTI ID: 6438375
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 50:6; ISSN JAHSAK; ISSN 0022-4928
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC CIRCULATION
CLIMATE MODELS
GEOGRAPHY
MATHEMATICAL MODELS
METEOROLOGY
MOUNTAINS
VORTICES