Analysis of dangerous weather events’ dynamics in Kharkiv for 2006-2015

The article covers features of the geographical location, natural conditions, technogenic and architectural planning features of the territories of Kharkiv city, which form a unique microclimate. The high-pressure zone crosses the area of the city, which is reflected in the anti-cyclonic activity. The big city increases the air temperature. This is facilitated by the work of transport, as well as thermal emissions from industrial enterprises, significant heating of buildings and asphalt covering. The city's climate is formed as a result of the interaction of large-scale atmospheric processes and the underlying surface. The repeatability dynamics of dangerous weather events in Kharkiv for 2006 - 2010 was analyzed, the total number and frequency of precipitation was 707 cases. The intensity of the rain according to the general indicators is maximal in May and minimal in February and January. This indicates the softness of the climate during the five-year period under research and the activity of the warm fronts in the winter. Taking into account the characteristics of the area, as well as the interaction of the air mass with the underlying surface of the city, it can be argued that the manifestation of the internal massive thermal thunderstorms is clearly expressed in Kharkiv. During the study of the number of fog events in Kharkiv it was established that this atmospheric event and the number of its cases are closely linked with industry, gas pollution and large buildings of the city. The highest repetition intensity of heavy snowfalls was found in the winter and in early March, due to the manifestation of the cyclone. In the next five years of 2011-2015, it was found that the number of atmospheric events differed from the previous period. We observe a significant decrease in rain frequency in winter, due to the fact that during this period anticyclones were active on the territory of Kharkiv and the cold fronts with cold and severe winters prevailed. The repeatability of the rain has increased in the spring and summer. Due to this factor also increased the number of thunderstorms. In winter, there is also a significant increase in the frequency of foggy days, due to the fact that the cold air dominated in the city, and the underlying surface was warmer, the city developed a network of heating, a large number of highways and industrial enterprises. Formation of the ice-crusted ground in 2011-2015 led to significant changes in the frequency of cases occurring in December and January. The number of blizzards has doubled. The repeatability dynamics of dangerous weather events in Kharkiv city for 2006-2015 has been analyzed and it has been established that during the studied period most of them were heavy rains, thunderstorms and fogs. Changes of the air temperature are characterized by unevenness, which also influenced the formation of dangerous weather events. The Icelandic minimum is a major factor influencing the manifestation of heavy rains in the summer, and heavy snowfalls in the winter, and fogs throughout the year. The Siberian maximum was clearly manifested in the winter, which formed a frosty and sunny weather with low temperatures. But alternation with cyclones led more and more to the formation of ice-crusted ground. The study of the repeated dangerous weather events has a scientific interest for the research of the climate of Kharkiv, as well as for construction climatology and for practical gardening consideration in the city.