The convective boundary layer (CBL) over domains with meso-γ-scale (2-20 km) heterogeneity is characterized by preferentially located, organized rolls of characteristic size equivalent to the length-scale of the heterogeneity. Additionally, random turbulent thermals also develop when the length-scale of the heterogeneity exceeds 5-10 km. This is due to a complex interaction between the horizontal pressure gradient generated by the heterogeneity and the buoynacy forcing. Consequently, the corresponding wavelet spectrum exhibits two peaks - one representing the turbulent thermals at a characteristic scale of about 1.5 times the CBL height and another denoting the organized eddies at a scale similar to that of the heterogeneity. This implies that subgrid-scale parameterizations in models with grid size larger than 5-10 km, which account only for random turbulence, are inadequate for heterogeneous domains. Also, this study may provide a more objective classification of scales of atmospheric processes.
|Original language||English (US)|
|Number of pages||4|
|Journal||Geophysical Research Letters|
|State||Published - Feb 15 2000|
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)