Ground-based 3 mm-wave radiometer for spectroscopic observations of atmospheric ozone and carbon monoxide

Ground-based remote sensing of the atmosphere at millimeter waves is widely used at present for investigation of stratospheric ozone and other trace gases [1, 2]. Millimeter wave techniques in this investigation have to provide for both receiver low noise in the broad band of frequencies and low systematic instrumental errors which finally determine sensitivity of the system. In this paper we present the 3mm-wave radiometer designed for spectroscopic observations of atmospheric ozone and carbon monoxide thermal emission lines at frequencies from 90 to 116 GHz. The construction, observing technique and calibration method used are described. Ozone and carbon monoxide spectral lines were measured at frequencies 110.836 and 115.271 GHz, respectively. On basis of observed lines we have carried out the comparative analysis of the experimental and calculated sensitivity of the radiometer.