JP5.21
The Response of Arctic Clouds to Surface Changes
Yinghui Liu, CIMSS/Univ. of Wisconsin, Madison, WI; and J. Key, X. Wang, B. Maddux, and S. Ackerman
Changes in Arctic climate system have been dramatic in recent years, including warming surface temperature, and sharp reductions in seasonal and perennial ice cover. Positive ice-albedo feedback is considered as the primary cause of these changes. Studies also show cloud plays an important role during these changes through interactions with atmosphere and surface. The recent dramatic changes in the Arctic climate system provide a valuable opportunity to study the cloud feedbacks.
Detecting cloud cover and retrieving cloud microphysical in polar regions are extremely difficult. Conventional observations of cloud are not sufficient for cloud feedback studies. Satellites provide long-term, relatively high-quality observations of cloud amount and its microphysical characteristics. Studies on Arctic climate system based on these data have shown significant progress. Data used in this study include cloud and surface observations from extended the AVHRR Polar Pathfinder (1982-2004) dataset, Moderate Resolution Imaging Spectrometer (MODIS) dataset, and other satellite datasets.
In this study, cloud macro-physical and microphysical characteristics are investigated as functions of surface conditions. Changes in cloud properties, including cloud cover, cloud top height, cloud droplet effective radius, cloud optical thickness, and correspondent changes in radiation fluxes are associated with the changes in surface type and properties, in an effort to determine the cloud feedbacks quantitatively. Preliminary results show significant changes in cloud amount, and cloud vertical structure with changes in surface conditions.
Joint Poster Session 5, Climate
Wednesday, 14 January 2009, 2:30 PM-4:00 PM, Hall 5
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