Ground-based millimeterwave instrument for measurement of stratospheric ClO using a superconductive (SIS) receiver Original Research Article

In 1997, Nagoya University and the National Institute for Environmental Studies (NIES) started a joint research project to develop a high-sensitivity ground-based millimeter-wave receiver capable of detecting thermal emission from the rotational lines of chlorine monoxide (ClO) and other constituents in the stratosphere. We have already constructed ozone sensors at 110 GHz employing an SIS receiver. In this project, we shall develop a 200–300 GHz SIS receiver system. The receiver noise temperature at 230 GHz is expected to be better than 50 K in single sideband. In 1999, we will install this instrument at Las Campanas Observatory at an altitude of ∼2400 m (29°S, 71°W) in Chile. This project is a first dedicated effort to measure O3, ClO and other constituents in South America where the polar vortex in the Antarctic sometimes tends to move away from the South Pole, and this study should be able to provide valuable information on their behavior, giving us a better understanding of the mechanism of O3 depletion in the mid-latitude region of southern hemisphere.