December 1, 1994Journal of Applied Meteorology
Impact of Land-Surface Moisture Variability on Local Shallow Convective Cumulus and Precipitation in Large-Scale Models
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Discussion
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Implication
Numerical simulation study reveals land-surface moisture variations enhance shallow convective precipitation, indicating landscape heterogeneity drives local cloud formation and rainfall.
Key Points
- To determine how land-surface moisture variability and landscape discontinuities influence the initiation of shallow convective cumulus clouds and the intensity and distribution of precipitation.
- Conducted numerical experiments using a high-resolution mesoscale cloud model to simulate shallow convection over heterogeneous surfaces.
- Evaluated the impact of varying land-surface forcing wavelengths against the local Rossby radius of deformation under different atmospheric thermodynamic structures and background winds.
- Landscape moisture discontinuities accelerated cloud onset and enhanced shallow convective precipitation, exhibiting the strongest effects in relatively dry atmospheres.
- Peak precipitation occurred when the wavelength of land-surface moisture forcing matched the local Rossby radius of deformation.
- Horizontal precipitation distribution was modulated by random turbulent thermal cells and sea-breeze-like mesoscale circulations, with maximum precipitation directly tracking normalized maximum latent heat flux.
Cite This Study
Chen et al. (1994) studied this question.