ИСТИНА

One of the most important parameters in modeling extreme events (cases of abnormally strong winds and, for example, tropical cyclones or medicanes) is the aerodynamic drag coefficient CD, which determines the vertical exchange of horizontal momentum between the atmosphere and the ocean. At high wind speeds, the near-surface layer of the atmosphere is saturated with spray and raindrops. There are foaming zones on the water surface, and the surface layer of water is saturated with air bubbles, which radically changes the processes of momentum, heat, and moisture exchange at the boundary of the ocean and atmosphere. At the same time, modern models of surface waves and atmospheric circulation, for example, WAVEWATCH III and WRF-ARW (WRF), respectively, are based on bulk formulas. They were obtained empirically for wind speeds not exceeding 20 m/s, extrapolated to high wind conditions typical of ocean storms, assuming that the small-scale processes driving turbulent transport remain the same as for moderate wind speeds. But recent studies show a qualitative difference between small-scale processes at high wind speeds compared to moderate ones. We analyzed and refined the parameterization of the underlying surface roughness coefficient in the WAVEWATCH III wave model and the WRF at-mospheric model under extreme weather conditions. Wind speed calculations were carried out within the framework of the WRF model in the northern part of the Atlantic Ocean along the path of Hurricane Irma. Wave parameters data were obtained from the WAVEWATCH III wave model. The period from 09/01/2017 to 09/08/2017 was considered, while the hurricane formed on 08/30/2017 and disintegrated on 09/12/2017. Estimates are given of the effect of including the exact amount of "parachute" type spray on the resulting aerodynamic drag coefficient. Preliminary results of the influence of the coefficient on the calculations of atmospheric parameters are also presented. The work was carried out within the framework of the FSTP topic "Investi-gation of processes in the boundary layers of the atmosphere, ocean and land waters and their parameterization in models of the Earth system".