Heating, moisture, and water budgets of tropical and midlatitude squall lines: Comparisons and sensitivity to longwave radiation

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1993)050<0673:HMAWBO>2.0.CO;2· OSTI ID:6779888

Tao, W K; Simpson, J; Chou, M D; Sui, C H; Ferrier, B; Pickering, K ^[1]; Lang, S ^[2]; Scala, J ^[3]

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1. NASA, Goddard Space Flight Center, Greenbelt, MD (United States)
2. Science Systems and Applications, Inc., Greenbelt, MD (United States)
3. National Research Council, Washington, DC (United States)

A two-dimensional, time-dependent, nonhydrostatic numerical cloud model is used to estimate the heating (Q[sub 1]), moisture (Q[sub 2]), and water budgets in the convective and stratiform regions for a tropical and a midlatitude squall line (EMEX and PRE-STORM). The model is anelastic and includes a parameterized three-class ice-phase microphysical scheme and longwave radiative transfer processes. A quantitative estimate of the impact of the longwave radiative cooling on the total surface precipitation and on the development and structure of these squall lines is presented. The vertical eddy moisture fluxes are a major contribution to the model-derived Q[sub 2] budgets in both squall cases. The vertical eddy heat flux is important for the PRE-STORM case due to the stronger vertical velocities in the PRE-STORM convective cells. The convective region plays an important role in the generation of stratiform rainfall for both cases. The transfer of condensate from the convective region became less important than the time in the stratiform water budget of the PRE-STORM system as it developed from its initial stage, such that the relative contribution to the stratiform water budget made by the horizontal transfer of hydrometeors from the convective region is similar at the mature stages of both systems. Longwave radiative cooling enhanced the total surface precipitation about 14% and 31% over a 16-h simulation time for the PRE-STORM and EMEX cases. The relative contribution to the stratiform water budget from the convective region is more sensitive to the longwave radiative cooling for the PRE-STORM case than for the EMEX case. The effect of radiative cooling is shown to increase as systems age in both cases. It was determined that the Q[sub 1] and Q[sub 2] budgets in the convective and stratiform regions are only quantitatively, not qualitatively, altered by the inclusion or exclusion of longwave radiative transfer processes. 55 refs., 9 figs., 5 tabs.

• OSTI ID: 6779888
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 50:5; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC PRECIPITATIONS
CLIMATE MODELS
CONVECTION
COOLING
ENERGY TRANSFER
HEAT FLUX
HEAT TRANSFER
HEATING
MASS TRANSFER
MATHEMATICAL MODELS
MOISTURE
RADIATIVE COOLING
TESTING
TROPICAL REGIONS
TWO-DIMENSIONAL CALCULATIONS
VALIDATION