Preliminary analysis of chlorine monoxide measurements made by the ground-based microwave receiver of the Plateau de Bure, France

摘要

A ground-based microwave receiver tuned to the 278 GHz hyperfine lines of chlorine monoxide has been operating at the Plateau de Bure in the French Alps (44.6/spl deg/N, 5.6/spl deg/E, 2550 metres high) since October 1992. This radiometer is part of the international Network for the Detection of Stratospheric Change and its aim is to monitor mid-latitude ClO on a regular temporal basis. The device is similar to the one operational in Mauna Kea, Hawai. Theoretical contributions of O/sub 3/, ClO and NO/sub 2/ and their associated diurnal variabilities are included in the radiative transfer calculation around 278.6 GHz. Sensitivity tests related to ClO activation in the lower stratosphere are also performed. Evidence suggests that spectra recorded from December 1993 do not show ClO activated by more than 0.5 ppbv in the lower stratosphere over Bure.