RESUMO
Results of the first year of data collection by the SAM (Stratospheric Aerosol Measurement) II satellite system are presented. Almost 10,000 profiles of stratospheric aerosol extinction in the Arctic and Antarctic regions are used to construct plots of weekly averaged aerosol extinction versus altitude and time and stratospheric optical depth versus time. Corresponding temperature fields are presented. These data show striking similarities in the aerosol behavior for corresponding seasons. Wintertime polar stratospheric clouds that are strongly correlated with temperature are documented. They are much more prevalent in the Antarctic stratosphere during the cold austral winter and increase the stratospheric optical depths by as much as an order of magnitude for a period of about 2 months. These clouds might represent a sink for stratospheric water vapor and must be considered in the radiative budget for this region and time.
RESUMO
On two nights in mid-September 1972, comparative measurements of stratospheric aerosol profiles, utilizing backscattered ruby laser light and direct in situ sampling were conducted over Laramie, Wyoming. The lidar backscattering and the particle number density profiles correlated well when the measured atmospheric molecular density profile was used to calculate the Rayleigh profile used in the lidar data reduction. The backscattered signal at 20 km was approximately 18% above Rayleigh and corresponded to a measured concentration of about one particle per cm(3) with diameters greater than 0.30 microm. Based on these initial comparative experiments, the ground-based lidar coupled with temperature soundings appears to be a possible method for determining the relative aerosol profile under present stratospheric loading conditions.
