Stochastic Modeling of the Process of Realization of the Precipitation-strong wind complex in the Territory of Georgia

Abstract

Georgia is characterised by dangerous natural meteorological events—extreme temperatures, heavy rainfall, blizzards, fog, strong and hurricane winds, etc., which create emergencies, cause significant material damage, and often cause human casualties. These events frequently occur together, compounding their effects and worsening the situation. The simultaneous occurrence of such events, in particular, strong winds and heavy rainfall, has not been studied for the territory of Georgia. This article looks at the likelihood of the most dangerous combinations of heavy rain and strong winds using probability theory, including the chances of these events happening at the same time, the chances of one event happening, the chances of both events happening if one occurs, and how these chances change over time and space in Georgia. The duration of recurrence periods of catastrophic rainfall and hurricane risk in the different physical geographical conditions of Georgia is also studied. The research utilised observational data from 21 weather stations of the National Environmental Agency, spanning from 1961 to 1990, to analyse strong winds and hurricane-related precipitations. It was identified that the maximum probability of the simultaneous occurrence of a complex of heavy rain and storms on the territory of Georgia is on the Likhi range (Mt. Sabueti) and is 15-23%; the minimum is in June and July, and the maximum is in September, while the probability of only one of the events on the Likhi range varies within 65-75% during the year. When one of the events occurs, the probability that the second event occurs in the Likhi range varies between 42–55%, with a minimum in September and a maximum in March. The highest average annual probability (15-20%) of the realisation of a storm in a complex with heavy rainfall is observed in the Likhi range – about 70 days a year. In the territory of Georgia, the recurrence period for catastrophic rainfalls and hurricanes is shortest on the Black Sea coast and Kolkheti Lowland, at 45 years. The obtained results are important for improving disaster preparedness and resilience in different regions of Georgia.