Articles | Volume 6, issue 12
Atmos. Meas. Tech., 6, 3359–3368, 2013
Atmos. Meas. Tech., 6, 3359–3368, 2013

Research article 09 Dec 2013

Research article | 09 Dec 2013

Cloud discrimination in probability density functions of limb-scattered sunlight measurements

E. N. Normand1, J. T. Wiensz2, A. E. Bourassa1, and D. A. Degenstein1 E. N. Normand et al.
  • 1Institute of Space and Atmospheric Studies, University of Saskatchewan, Canada
  • 2SRON Netherlands Institute for Space Research, Utrecht, Netherlands

Abstract. A technique characterizing the distribution of cirrus cloud-top occurrences from the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb-scattering radiance profiles is presented. The technique involves computing scattering residual profiles by comparing normalized measured radiance and modelled molecular radiance profiles where enhancements in the measured radiance indicate the presence of clouds. Probability density functions of scattering residuals show the distribution is not a continuum measurement; there is a distinction between the cloudy and cloud-free conditions. Observations show high cloud-top occurrences in the upper troposphere and lower stratosphere region above Indonesia and Central America. Results obtained using this technique with OSIRIS measurements are compared to those obtained by Sassen et al. (2008) with Cloud-Aerosol Lidar Pathfinder Satellite Observations (CALIPSO) nadir measurements and to those obtained by Wang et al. (1996) with Stratospheric Aerosol and Gas Experiment (SAGE) II solar occultation measurements.