DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, Mixed-phase clouds and icing research. Part I: Collocated aircraft and satellite observations Objectives: u Understand characteristics of mixed-phase and supercooled liquid clouds through aircraft and satellite observations u Improve detection and prediction of icing conditions through improvements to satellite retrievals and numerical model forecasts u Improve knowledge and training of forecasters in the field Curtis J. Seaman, Yoo-Jeong Noh, Thomas H. Vonder Haar In collaboration with Peter Rodriguez and David Hudak (Environment Canada)

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, DoD Relevance: u u Mid-level clouds (altocumulus and altostratus) cover % of the Earth and often contain supercooled liquid water, which causes aircraft icing u u UAS/UAV have little to no de-icing capabilities u u They form at mission critical altitudes and impact pilot visibility, battlefield damage assessment, refueling, target detection, laser communication u u These clouds are difficult to forecast and can last 12+ hours

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, Mixed-phase clouds and icing research Deliverables: u CG/AR Technical report: t Vonder Haar, Noh, Seaman and Kankiewicz (2011): Synopsis of Mixed-phase Cloud Research and Results u Journal paper: t Noh, Seaman, Vonder Haar, Hudak and Rodriguez (2011): Comparisons and analyses of aircraft and satellite observations for wintertime, mixed-phase clouds. Journal of Geophysical Research, in revision. u Conference papers/posters: t BACIMO, Omaha, NE, April 2010 t IGARSS, Honolulu, HI, July 2010

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, Convair-580CloudSatCLEX-10: u Extensive field campaign in collaboration with the Canadian CloudSat/CALIPSO Validation Project (C3VP) u 31 October 2006 – 1 March 2007 u 28 flights totaling 107 hours (CG/AR funded ~20%) u Collocated CloudSat / CALIPSO (A-Train) and aircraft measurements, often in mixed-phase clouds Mixed-phase clouds and icing research ~1828 UTC on 05 Nov 2006 Aqua MODIS: Cloud top temperature CloudSat CPR reflectivity and cloud classification

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, MODIS Cloud Phase 31 Oct Nov Feb 2007 u u Research aircraft was flown through clouds Aqua MODIS classified as “uncertain”, “mixed-phase” or “ice” u u All three cases were “mixed-phase” t t 31 Oct and 5 Nov had patchy thin cirrus overhead

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, October 2006 Supercooled liquid at -23 o C No liquid below -20 o C in CloudSat Gray shading = CloudSat Cloud Mask

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, November 2006 Gray shading = CloudSat Cloud Mask Supercooled liquid and icing! Cloud Mask and Cloud Water Content don’t always agree

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, November 2006 Image: Kevin Strawbridge, EC u u King and Nevzorov probes detected ~500 m thick cloud layer t t 2D optical array probes not functional on this flight u u CloudSat detected ~ 2 km thick cloud u u Could this be due to precipitating ice virga (detected by lidar at CARE)? If so, CloudSat assumes it is liquid

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, February 2007 Average IWC derived from 2D optical array probes using three different methods Supercooled liquid at -28 o C that CloudSat flags as ice Gray shading = CloudSat Cloud Mask

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, ECMWF-AUX products Temperature errors ~2-3 o C Pressure errors ~ 10 mb 31 Oct Nov Feb 2007

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, Conclusions Temperature ( C) o Water Fraction Cloud Water (Model-Fletcher) Cloud Water (Observed) NCEP GFS Model Water Distribution u u CloudSat uses the same assumptions about cloud phase that many (most?) models use u u CloudSat puts the IWC at cloud top, LWC at cloud base for clouds at -20 o C t t Will assume ice virga is liquid in temperatures above -20 o C u u Magnitudes of LWC, IWC from CloudSat are generally within the error of the aircraft measurements u u Cloud Mask and CWC retrieval don’t necessarily agree on cloud boundaries u u Technical report complete

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, October 2006 CloudSat CPR Convair Ka-band u u CloudSat correctly classified this cloud as altostratus u u Differences in aircraft vs. CloudSat radar are evident u u At the time of the CloudSat overpass, the aircraft was 214 m from the sub-satellite point!

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, November 2006 CloudSat CPR Convair Ka-band u u CloudSat correctly classified this cloud as altocumulus u u CloudSat saw the aircraft! u u At the time of the CloudSat overpass, the aircraft was 356 m from the sub-satellite point

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, February 2007 CloudSat CPR Convair Ka-band u u MODIS classified cloud as “ice”, yet had significant supercooled liquid u u CloudSat correctly classified this cloud as altostratus u u Gap in CloudSat data due to signal contamination with airborne W-band radar u u At the time of the CloudSat overpass, the aircraft was 111 m from the sub-satellite point!

DoD Center for Geosciences/Atmospheric Research at Colorado State University Annual Review March 8-9, Effective Radius 31 Oct Nov Feb 2007 u u Liquid droplet effective radius from CloudSat shows general agreement with FSSP effective radius