Ice polar stratospheric clouds detected from assimilation of Atmospheric Infrared Sounder data

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Read Full Article (file size: 7997587 bytes) Cited by GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L16802, doi:10.1029/2007GL029415, 2007 Ice polar stratospheric clouds detected from assimilation of Atmospheric Infrared Sounder data Ivanka Stajner Science Applications International Corporation, Beltsville, Maryland, USA Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Craig Benson Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Goddard Earth Sciences and Technology Center, University of Maryland Baltimore County, Baltimore, Maryland, USA Hui-Chun Liu Science Applications International Corporation, Beltsville, Maryland, USA Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Steven Pawson Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Nicole Brubaker Science Applications International Corporation, Beltsville, Maryland, USA Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Lang-Ping Chang Science Applications International Corporation, Beltsville, Maryland, USA Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Lars Peter Riishojgaard Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Goddard Earth Sciences and Technology Center, University of Maryland Baltimore County, Baltimore, Maryland, USA Ricardo Todling Science Applications International Corporation, Beltsville, Maryland, USA Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Abstract A novel technique is presented for the detection and mapping of ice polar stratospheric clouds (PSCs), using brightness temperatures from the Atmospheric Infrared Sounder (AIRS) “moisture” channel near 6.79 μm. It is based on observed-minus-forecast residuals (O-Fs) computed when using AIRS radiances in the Goddard Earth Observing System version 5 (GEOS-5) data assimilation system. Brightness temperatures are computed from six-hour GEOS-5 forecasts using a radiation transfer module under clear-sky conditions, meaning they will be too high when ice PSCs are present. We study whether the O-Fs contain quantitative information about PSCs by comparison with sparse data from the Polar Ozone and Aerosol Measurement (POAM) III solar occultation instrument. AIRS O-Fs lower than −2 K generally coincide with PSCs observed by POAM III. Synoptic maps of AIRS O-Fs lower than −2 K are constructed as a proxy for ice PSCs. These are used to investigate spatio-temporal variations of Antarctic PSCs in the year 2004. Received 19 January 2007; accepted 16 July 2007; published 16 August 2007. Keywords: data assimilation; infrared radiances; ice clouds. Index Terms: 0394 Atmospheric Composition and Structure: Instruments and techniques; 0340 Atmospheric Composition and Structure: Middle atmosphere: composition and chemistry; 0341 Atmospheric Composition and Structure: Middle atmosphere: constituent transport and chemistry (3334); 0321 Atmospheric Composition and Structure: Cloud/radiation interaction. Read Full Article (file size: 7997587 bytes) Cited by Citation: Stajner, I., C. Benson, H.-C. Liu, S. Pawson, N. Brubaker, L.-P. Chang, L. P. Riishojgaard, and R. Todling (2007), Ice polar stratospheric clouds detected from assimilation of Atmospheric Infrared Sounder data, Geophys. Res. Lett., 34, L16802, doi:10.1029/2007GL029415. Copyright 2007 by the American Geophysical Union.

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