Remote sensing of Clouds
CIWSIR - Cloud Ice Water Sum-millimetre Imaging Radiometer

Klaus Kunzi (PI), Stefan Buehler, Georg Heygster, Jungang Miao
Funding: ESA 

Cirrus clouds are global in nature and occur primarily in the upper troposphere and lower stratosphere. These clouds are composed almost entirely of ice crystals. Information on cirrus cloud parametres is crucial to the development of cirrus cloud forecast models, the upgrading of real-time global cloud analysis, and the investigation of cloud feedback in global climate change. Recently, radiometry in the submillimetre band (up to 1000 GHz) has been shown to be a very effective tool in sensing cirrus clouds parametres. The simulation studies of Evans et al. show that the sensitivity of submillimetre radiometry to the total columnar ice content increases with frequency and that at frequencies above approximately 500 GHz the radiometric sensitivity is high enough to measure cirrus cloud properties. 

The IUP has proposed to ESA the sensor CIWSIR as an Earth Expolorer Opportunity mission in January 2002.  As a result, the mission is among the ones where ESAC has recommended further actions.  Currently, ESA is undertaking actions to implement the recommendations, the most important beeing an airborne demonstration mission. 
                       ESA proposal   (pdf) 
                       ESA outline proposal (pdf)
                       EUMETSAT presentati on by Prof. Kunzi (ppt) 

Currently IUP is planning to submit CIWSIR as a national Earth Observation Mission in November 2003 in response to the DLR AO.
                               Letter of Interest (in German, rtf)

Related Publications

• Miao, J., G. Heygster, K. Kunzi 2000: Ice clouds and background water vapor by sub-millimeter and very-high frequency microwave radiomery. Appendix 7 of final report to EU project CLOUDS - A cloud and radiation monitoring satellite.
• Miao, J., S. Buehler, K. Kunzi 2001: The polarization characteristics of randomly oriented non-spherical ice particles in mm and sub-mm frequency range: Implications to the remote sensing of cirrus clouds using satellite microwave radiometry. Proc. IGARSS 2001, 2442-2444. 
• Heygster, G., J. Miao, and S. Buehler 2002: Single scattering of partly oriented aspherical cloud ice particles at sub-millimeter wavelenths. Proc IGARSS 2002.
• Miao, J., T. Rose, K. Kunzi, P. Zimmermann 2002: A future millimeter/sub-millimeter radiometer for satellite observation of ice clouds. Int. J. Infrared & Millimeter Waves 23,8 (aug 2002) 1159-1170
• Miao, J., K.-P. Johnsen, S. Buehler, A. Kokhanovsky 2003: The potential of polarization measurements from space at mm and sub-mm wavelengths for determining cirrus cloud parameters. Atmos. Chem. Phys. 3, 39-48.