Space-based thin cirrus cloud observations of the future

While thin cirrus clouds have a minor impact upon the global radiation budget, they have been implicated to play a major role in controlling the water vapor input into the lower stratosphere. Insight into thin cirrus cloud behavior has relied to a large extent upon the 20 year data set from the Stratospheric Aerosol and Gas Experiment II (SAGE II). Since the last data collection event by SAGE II occurred in late August 2005 a new source of observations is needed to further our understanding of thin cirrus as global climate changes. One such new source of data is observations of light scattered from the limb of the atmosphere, limb scatter. Currently several space-based instruments are making limb scatter measurements: the Optical Spectragraph and Infrared Imager Suste, (OSIRIS), the Stratospheric Aerosol and Gas Experiment III (SAGE III), and the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). In addition, during the 2010-2030 time frame the Ozone Mapping Profiler Suite, scheduled to fly on the National Polar orbiting Operational Environmental Satellite System (NPOESS) and the NPOESS Preparatory Project (NPP), will make limb scatter measurements primarily for ozone profiling, but have channels sensitive to cirrus clouds. Here we examine the potential of limb scatter measurements to continue the global data set begun by SAGE II and increase our understanding of the role thin cirrus plays in the upper atmosphere. A key element to this understand is some knowledge of the aerosol loading in the upper atmosphere, which again in the past has been supplied by SAGE II observations and can be supplied by limb scatter observations.