Microwave Radiometer for Spectral Observations of Mesospheric Carbon Monoxide at 115 GHz Over Kharkiv, Ukraine

We present the results of the development of high sensitivity microwave radiometer designed for observation of the atmospheric carbon monoxide (CO) emission lines at 115 GHz. The receiver of this radiometer has the double-sideband noise temperature of 250 K at a temperature of 10A degrees C. To date, this is the best noise performance for uncooled Schottky diode mixer receiver systems. The designed radiometer was tested during the 2014-2015 period at observations of the carbon monoxide emission lines over Kharkiv, Ukraine (50A degrees N, 36.3A degrees E). These tests have shown the reliability of the receiver system, which allows us in the future to use designed radiometer for continuous monitoring of carbon monoxide. The first observations of the atmospheric carbon monoxide spectral lines over Kharkiv have confirmed seasonal changes in the CO abundance and gave us reasons to assume the spread of the influence of the polar vortex on the state of the atmosphere up to the latitude of 50A degrees N where our measurement system is located