Conclusions

1. CloudSat CloudSat 1825 UTC on 25 Feb 2007 Aqua MODIS: Cloud top temperature CloudSat CPR cloud classification 1825 UTC on 05 Nov 2006 Aqua MODIS: Cloud top temperature CloudSat CPR cloud classification LWC/IWC and Temperature Supercooled liquid layer from CALIPSO Supercooled liquid layer from CALIPSO Convair-580 Convair-580 A COMPARISON BETWEEN SATELLITE AND AIRCRAFT OBSERVATIONS FOR WINTERTIME NON-PRECIPITATING MIXED-PHASE CLOUDS Yoo-Jeong Noh, Curtis Seaman, Thomas Vonder Haar(DoD Center for Geosciences/Atmospheric Research, CIRA/Colorado State University, Fort Collins, CO) Background and Motivation Comparisons between Satellite and Aircraft Data 05 November 2006 25 February 2007 MODIS Cloud Phase MODIS Cloud Phase Clouds are a crucial factor in the study of weather forecasting and global climate. In the mid- troposphere, mixed-phase clouds, in which supercooled liquid water coexists with ice, are more common than single-phase clouds. However, many details of the microphysical and dynamic processes that determine their formation and dissipation are not fully understood. The Convair-580 flew a spiral descent around the CloudSat ground track 5 min. after the CloudSat overpass in a cloud layer MODIS classifies as “ice” but aircraft probes show is mixed-phase. The Convair-580 descended along the CloudSat ground track 15 min. after the CloudSat overpass in a cloud layer MODIS classifies as “uncertain.” Aircraft probes Aircraft probes The fields of remote sensing, radiative transfer, numerical weather prediction (NWP), and climate modeling commonly utilize gross assumptions about mixed-phase cloud properties due to a lack of extensive in situ observations. Altitude Altitude LWC/IWC comparison LWC/IWC comparison In this study, extensive in situ observations of mixed-phase clouds have been collected from a research aircraft with coincident remote sensing data from the A-Train satellite constellation. These aircraft observations have been analyzed and compared with satellite retrievals from CloudSat and MODIS (Aqua) for two cases of mid-level, mixed-phase clouds from the joint C3VP/CLEX-10 field experiment. LWC LWC Icing Icing The Cloud Layer EXperiment (CLEX) is an ongoing research program funded by the Department of Defense's Center for Geosciences/Atmospheric Research at CIRA/Colorado State University since 1996, dedicated to understanding microphysical properties, dynamics, and morphology of non-precipitating, midlevel, mixed-phase clouds. CLEX-10 collaborated with the Canadian CloudSat and CALIPSO Validation Project (C3VP) over southern Ontario & Quebec, Canada from 31 October 2006 to 01 March 2007. During four IOPs, the Canadian National Research Council’s (NRC) Convair-580 research aircraft flew underneath the A-Train satellites (Aqua, CloudSat, CALIPSO, PARASOL, Aura) equipped with extensive instrumentation including cloud microphysical probes (both optical and hot wire), airborne lidar, W- and X- band radars and an ice nuclei counter. Temperature Temperature CloudSat reflectivity CloudSat LWC/IWC CloudSat reflectivity CloudSat LWC/IWC Aircraft path Aircraft path Satellite Measurements Aircraft Measurements Conclusions • During C3VP/CLEX-10, a great combination of observations of midlevel mixed-phase clouds was obtained from aircraft, satellites and the surface observations. The Convair-580 research aircraft flew above, below and in clouds while the A-Train satellites passed overhead. • Aircraft observations during C3VP/CLEX-10 reveal significant amounts of supercooled liquid water at temperatures down to -32 oC. This contradicts the CloudSat cloud water content retrieval, which assumes all cloud water below -20 oC is ice. This is clearly seen in the 25 February 2007 case shown above. These results impact NWP, radiative transfer and climate modeling, which use the same assumption as the CloudSat water content retrieval. • Water content amounts retrieved by CloudSat agree with the aircraft within the error of the microphysical probes, except in terms of cloud phase. For the 5 November 2006 case, CloudSat likely sees precipitating ice virga (based on ground based lidar data not shown), yet assumes it is liquid. • The MODIS cloud phase retrieval has been compared with aircraft observations for two cases of mixed-phase clouds: one was classified as “ice” and the other as “uncertain.” • The C3VP/CLEX-10 data set is providing valuable information for understanding and improving forecasts and retrievals of mixed-phase clouds and icing. This data is now being used to provide major improvements to satellite detection algorithms as well as numerical model parameterizations for these clouds. This research was supported by the Department of Defense Center for Geosciences/Atmopheric Research at Colorado State University under Cooperative Agreement W911NF-06-2-0015 with the Army Research Laboratory. Noh@cira.colostate.edu or Seaman@cira.colostate.edu