European Conference on Applications of Meteorology/ EMS Annual Meeting Meteorological conditions of ice and snow accretion in the southern and central regions of Ukraine Khomenko Inna, Odessa State Environmental University, Ukraine

In order to study conditions of atmospheric icing near the surface such as glaze, soft and hard rime, snow accretion, the data for 39 stations of Ukraine are used for period of 1996-2007. Database contains temperature, wind speed and wind direction in the beginning of icing accretion and at the moment that the accretion reached maximum in the size.

Vinnytsia region Kirovohrad region Mykolayv region Kherson region Odessa region

Classification of sites according to the severity of icing Intensity of icing is calculated according the formula (1) after integration of formula (1) we obtained (1) (2) collision efficiency, liquid water mass/unit volume, sticking efficiency, wind speed, freezing efficiency, cross-sectional area of object.

Classification of sites of Ukraine according to the severity of icing

Frequency distribution of surface temperature in the beginning of the atmospheric icing near the surface The most glaze events (about 87%) are connected with the narrow negative temperature from 0 to -4 C. GLAZE 51% In a half of these cases the slightly negative temperatures are observed from -1 to 0. 87% 7

Frequency distribution of surface temperature in the beginning of the atmospheric icing near the surface HARD RIME 32% For the hard rime the more wide temperature interval (-8…-1) is typical. 82% 32% from these cases are associated with temperatures from -6 to -4. 8

in which 74% of all the soft rime cases occur. Frequency distribution of surface temperature in the beginning of the atmospheric icing near the surface The soft rime events are distributed almost evenly in the interval -20…-6, in which 74% of all the soft rime cases occur. SOFT RIME The most cases take place under -16…-10 temperature. 58% 74% 9

Approximately 90% of the wet snow cases Frequency distribution of surface temperature in the beginning of the atmospheric icing near the surface WET SNOW 93% Approximately 90% of the wet snow cases are related with the -1…+1 C interval. 10

Frequency distribution of wind direction in the beginning of atmospheric icing near the surface The most number of hard and soft rime cases are reported under calm (soft rime 38%, hard rime 25%). For the hard rime the remaining cases are distributed evenly in the other graduations. And for the soft rime the north direction with the highest frequency is obtained. 14%

Frequency distribution of wind direction in the beginning of atmospheric icing near the surface Frequency of the glaze cases under the calm is significant. 66% 8% 60% For the glaze surface wind is characterized by high occurrence frequency of north, north-east, east and south-east directions with the maximum for north-east and east directions.

Frequency distribution of in the duration of accretion of ice. Frequency distribution of wind direction at the moment, in which the icing accretion reached maximum in size Frequency distribution of the wind direction are almost unchangeable in the duration of accretion of ice.

Frequency of occurrence of glaze in the beginning of the event as a function air temperature and wind speed

Frequency of occurrence of hard rime in the beginning of the event as a function air temperature and wind speed

Frequency of occurrence of soft rime in the beginning of the event as a function air temperature and wind speed

Frequency of occurrence of wet snow in the beginning of the event as a function air temperature and wind speed

The further steps: similar technique is applied to the other regions of Ukraine; application of regression analysis to the wind-temperature plot, obtained for different types of icing, and dividing the icing into different areas by temperature and wind speed for different regions of Ukraine; classification of the territory of Ukraine, using the site icing index.