Ukrainian Hydrometeorological Research Institute, Kyiv - Ukraine
This contribution presents results of numerical simulation of meso- and microstructure of winter frontal mixed clouds and precipitation fields. The two-dimensial time-depended numerical models with detailed microphysics were constructed. Initial cross-sections of frontal systems were based on rawinsondes and aircraft data.
The fronts under study exibit a complex system of large-scale whirls occpying lower layers of troposphere and connected with them updraft-downdraft parsels. Maximum values of updraft speeds reach tens of cm/s.
When updraft parcels are located at small hights (T > -25 °C) the ice nucleation and precipitation formation have insufficient efficiency, the total liquid water content can reach 1 mm.
In case of high updraft parcels ( T < -31 °C) and high concentration of ice nuclei precipitation formation processes are very intensive. After of 4-6 hours of cloud evolution the complete crystallization takes place and the precipitation rate can reach tens mm/h.
Thus it is possible to identify heavy precipitation mesosones using satellite data by high, thick very dense crystal parcels (bands).