Thermal Effect in Surface Atmosphere of the Solar Eclipse on June 10, 2021

The solar eclipse (SE) on June 10, 2021, was annular and a member of Saros 147. The first contact occurred at 08:12:20 UT on June 10, 2021, and the fourth contact occurred at 13:11:19 UT. The maximal SE magnitude was observed from 09:49:50 to 11:33:43 UT. The annularity took place from 10:33:16 to 10:36:56 UT. The solar eclipse began over the territory of Canada. The shadow moved across Greenland (where the annularity took place), the Arctic Ocean, the North Pole, New Siberia Island, and the Russian Federation. The partial eclipse was observed in Mongolia, in a major part of China, in the northeast of the United States, in North Alaska, all over the Arctic Ocean, and in the North Atlantic, as well as over a major part of Ukraine, except for the Odessa, Nikolaev, and Kherson regions and Crimea. In this work, the observations of the thermal (temperature) effect of the SE of June 10, 2021, in the surface air layer in the city of Kharkiv are described; the thermal effects of eight SEs that occurred in the same region in 1999–2021 are compared. The observations of the effects in the surface air layer were made at Karazin National University Radiophysics Observatory, in the vicinity of Kharkiv. The air temperature, atmospheric pressure and humidity, and the wind speed and direction were measured with standard instrumentation. The temperature measurement accuracy was 0.1°C. The solar eclipse energy balance is estimated. The internal energy of gas in the surface atmosphere has been shown to decrease by ~5.3 × 10¹⁸ J due to the SE, which corresponds to an average power of 1.2 PW. The specific energy and power were 6.5 kJ/m³ and 1.4 W/m³. The variations in the air temperature of the surface atmosphere were observed during the day of the solar eclipse and on the reference days. They were analyzed along with the tropospheric weather for those days. The weather was not favorable for observations of the thermal effect of the eclipse. The atmospheric cooling occurring during the eclipse magnitude maximum is estimated; the decrease in the temperature amounted to approximately 1°C. The differences in the thermal effects during the eight SEs compared are explained by different seasons, local time, cloud structure, state of the Earth’s surface, and atmospheric convection.