Cloud Cells from Satellite Measurements and Convective Energy Balance during the Cold Air Invasion in the Atmosphere over the Black Sea
In this paper we perform a case study of cold air invasion during winter in the Black Sea Region in January 2010. Using WRF numerical model we simulated intensive convection over the sea on January 25 and verified the modeling results using satellite data on cloudiness, cloud top temperature, and humidity. It was shown that according to both the modeling results and the satellite data there was mixed convection over the sea, but convective cells dominated and played the main role in the mixing in the atmospheric boundary layer (ABL). It was shown that the model captured the increase of cloud top height over the sea. Using spectral analysis of vertical moisture flux fields we showed that the model correctly reproduced the horizontal size of cloud structures near the shore. It was found out from the modeling results and satellite pictures that horizontal size of convective cells over the sea increased downwind. Also, we studied main terms in the convective kinetic energy (CKE) equation. In particular, we considered CKE generation in the ABL due to pressure pulsations and buoyancy, as well as its decrease due to turbulent dissipation and convective advection.