Abstract : 2G.12
Numerical investigation of the Caucasian region relief influence on distribution of hydrometeorological fields

Avtandil Kordzadze, Alexandre Surmava, Demuri Demetrashvili
avtokor@ig.acnet.ge
M. Nodia Institute of Geophysics

By numerical integration of the non-adiabatic, non-stationary and non-linear equations of atmosphere hydrothermodynamics the influence of the Caucasian region relief on a space distribution of meteorological fields is investigated. The dimensionless vertical coordinate, which in numerical experiments enables approximate the real relief with high accuracy, is used. The air motions over Caucasian Region in presence of large-scale background western, eastern, northern and southern winds are simulated. It is shown that the action of the relief on the basic four types of large-scale movements can cause essential change of a current field in the lower troposphere and forms mesoscale structures of the wind, temperature, pressure and moisture fields.

Influence of the Caucasian relief on the wind field is especially essential in the low troposphere. In case of the background western wind "blocking" of background current by mountain ridges is received.

In case of the eastern background wind the effect of "blocking" is absent. Air "is soaked up" between the Main and Small Caucasian Ridges and passing through the Likchi Ridge extends above the Kolhida Lowland and Black Sea.In case of flow the Main Caucasian Ridge by southern background wind the cyclonic and anticyclone mesoscale atmospheric vortexis are formed and over a leeside of the Main Caucasian Ridge a inverse flow is obtained. In case of flow of the relief by background northern wind the cyclonic and anticyclone mesoscale atmospheric vortexis are formed only.

For fields of vertical speed, humidity and cloudy systems complex mesoscale structures are received. Their spatial distributions in some cases considerably differ from spatial distributions received by means of numerical weather forecasting models.