Combined System for Observations of Tropospheric and Stratospheric Thin Clouds

Abstract

A balloonborne sonde and a polarization lidar have been developed to make combined observations of thin tropospheric and stratospheric clouds. In their first application these instruments have been used in a campaign organized to study Antarctic polar stratospheric clouds (PSCs), which are deeply involved in the process of ozone depletion. The sonde collects cloud particles larger than 4 µm in diameter on a transparent impactor and observes them by means of a CCD (charge coupled device) camera microscope. Images are transmitted in real time to the ground station for recording and analysis. Shape, dimension, and size distribution of the particles are obtained from these frames. The lidar provides complementary information about the cloud optical depth, backscattering, depolarization, vertical distribution, and temporal evolution. Characteristics of both instruments are described. The experiments performed during the 1990 spring campaign at McMurdo Station, Antarctica, are discussed, and some results are reported to show the capabilities of the combined system.