Numerical study of stratified airflow over mesoscale heat sources with application to Carolina coastal frontogenesis

Journal Article · Sun Dec 01 04:00:00 EST 1996 · Monthly Weather Review

DOI:https://doi.org/10.1175/1520-0493(1996)124<2807:ANSOSA>2.0.CO;2· OSTI ID:484434

Xie, L; Lin, Y L ^[1]

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1. North Carolina State Univ., Raleigh, NC (United States)

This paper presents the results from a numerical investigation of the responses of stratified airflow to prescribed near-surface mesoscale axisymmetric (circular) and elongated (elliptical) heat sources under uniform basic wind conditions using a simple three-dimensional model. Model results indicate that the structure of the response depends on the Froude number (Fr = V/NH) and the Rossby number (Ro = V/fL) associated with an axisymmetric thermal forcing, where H and L are the vertical and horizontal scales of the heat source, V the wind speed, N the Brunt-Vaeisaelae frequency, and f the Coriolis parameter. However, the response to an elongated thermal forcing depends not only on the Froude and Rossby numbers, but also on the ratio of the alongstream scale (L{sub s}) to the cross-stream scale (L{sub n}) of the heat source, which are determined by the horizontal shape of the heat source and the direction of the basic flow. When L{sub s}/L{sub n} is less than 1, that is, the heat source is elongated in the cross-stream direction, the response resembles that of two-dimensional solutions. However, when this ratio is > 1, that is, the heat source is elongated in the alongstrem direction, the response appears quite different. In this case, the heat-induced vertical motion is primarily upward but confined to the lower atmosphere. The horizontal distribution of surface sensible heat fluxes observed off the Carolina coast often appears to be elongated along the Gulf Stream front. These surface heat sources can induce coastal frontogenesis. 33 refs., 14 figs., 1 tab.

• DOE Contract Number: FG09-85ER60376
• OSTI ID: 484434
• Journal Information: Monthly Weather Review, Journal Name: Monthly Weather Review Journal Issue: 12 Vol. 124; ISSN MWREAB; ISSN 0027-0644
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
99 GENERAL AND MISCELLANEOUS
AIR FLOW
COASTAL REGIONS
HEAT FLUX
HEAT SOURCES
HURRICANES
MATHEMATICAL MODELS
METEOROLOGY
NUMERICAL ANALYSIS
STORMS
STRATIFICATION