RESULTS OF NUMERICAL SIMULATION OF MARINE STRATOCUMULUS CLOUDS

N. F. Veltishchev and A. I. Lebedev

Results of numerical simulation of marine stratocumulus clouds are presented under an a priori specified rate of radiative cooling of their tops. It is found that the quasistationary convective flows developing in the upper part of the boundary layer as a result of cloud top radiative cooling can exist only under conditions of diurnal modulation of radiative heat fluxes at the cloud top: its nighttime cooling and daytime heating. The model integration for a time period up to ten days showed that, under a periodic regime of radiative excitation of convective flow, cloud layer thickness, cloud liquid-water content, and cloud boundary and inversion base positions are almost independent on time. Vertical distribution of heat fluxes due to water vapor condensation, cloud particle evaporation, and convective mixing supports temperature inversion, rather than destroys it; this leads to a long lifetime of stratocumulus cloud layers under temperature and humidity stratification typical of the subtropical oceanic areas with a comparatively low water temperature in the cold oceanic currents.

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