COMBINED SYSTEM FOR OBSERVATIONS OF TROPOSPHERIC AND STRATOSPHERIC THIN CLOUDS

A balloonborne sonde and a polarization lidar have been developed to m ake combined observations of thin tropospheric and stratospheric cloud s. In their first application these instruments have been used in a ca mpaign organized to study Antarctic polar stratospheric clouds (PSCs), which are deeply involved in the process of ozone depletion. The sond e collects cloud particles larger than 4 mum in diameter on a transpar ent impactor and observes them by means of a CCD (charge coupled devic e) camera microscope. Images are transmitted in real time to the groun d station for recording and analysis. Shape, dimension, and size distr ibution of the particles are obtained from these frames. The lidar pro vides complementary information about the cloud optical depth, backsca ttering, depolarization, vertical distribution, and temporal evolution . Characteristics of both instruments are described. The experiments p erformed during the 1990 spring campaign at McMurdo Station, Antarctic a, are discussed, and some results are reported to show the capabiliti es of the combined stem.