Extended Abstract (696K)1.3
Cirrus Cloud and Polar Stratospheric Cloud Measurements from CALIPSO
M. Patrick McCormick, Hampton University, Hampton, VA; and H. Nazaryan and M. T. Hill
Using the first year of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data, a study of the global and seasonal distribution of cirrus clouds, that have been identified as one of the most uncertain components in weather and climate studies, and of Polar Stratospheric Clouds (PSCs), important as sites for heterogeneous chemistry and polar ozone loss, have been conducted. Few instruments can deduce the global presence of cirrus clouds, especially sub-visual clouds and those of low optical thickness. Similarly, few remote sensors can produce the vertical and spatial distribution of PSCs each day over the local winter and early spring periods. Satellite lidar has the ability to profile multi-layer cloud structures and it is particularly useful for the detection of sub-visible cirrus, and PSCs over the poles where CALIPSO's coverage is the most spatially dense. satellite mission provides comprehensive observations of cloud vertical structure on a near global scale. We investigate the latitude-longitude and vertical distributions of PSCs and cirrus, and thickness of cirrus clouds. In addition, we classify PSCs by type (solid/liquid nitric acid and water ice) using the depolarization ratio and backscatter ratio from CALIOP at 532 nm wavelength, and GMAO temperature data. For example, our investigation of top-layer cirrus clouds shows maximum occurrence frequency of up to 70% near the tropics at the 100° - 180° longitude band. We also analyze the seasonal behavior of the cirrus cloud frequency. Our results show large latitudinal movement of cirrus cloud cover with the changing seasons. Obviously, PSCs have a much higher frequency of occurrence over Antarctica in winter than over the Arctic. This paper will describe and characterize the global distribution of cirrus clouds and PSCs and compare these data with previously published data sets.
Session 1, RADAR/LIDAR Studies from Space
Tuesday, 22 January 2008, 9:00 AM-9:45 AM, 210
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