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IHL: Wiki Overview

A page where NCAR collaborators and science partner stakeholders can view the latest IHL and NIRSS analysis. The purpose of this page is to facilitate collaboration and make the project findings readily accessible.

IHL: Program Background

     Overview

     2013 AMS Radar Conference

     2012 IHL Final Report

     2010 IHL Final Report

     Current IHL Tasks and Deliverables

Case Studies

          Overview of Cases               

                View January 27 2012 at KCLE
                View February 02, 2012 at KCLE
                View February 08, 2012 at KCLE
                View February 10, 2012 at KCLE
                View February 12, 2012 at KCLE
                View February 14, 2012 at KCLE
                View February 22, 2012 at KCLE
                View February 24, 2012 at KCLE
                View February 25 - 26, 2012 at KCLE
                View November 07, 2012 case at KJFK
                View November 08, 2012 case at KJFK
                View November 10, 2012 case at KJFK
                View November 10-11, 2012 case at KFTG
                View December 28-30, 2012 case at KCLE                   
                View February 21, 2013 case at KSGF
                View February 21-22, 2013 case at KSTL
                View February 22, 2013 case at KCLE
                View March 19-22, 2013 case at KBUF
                View April 09-10, 2013 case at KFSD
                View April 17, 2013 case at KFTG
                View April 20, 2013 case at KCLE
                View April 23, 2013 case at KDDC
                View April 25, 2013 case at KCLE
                View May  12, 2013 case at KCLE                               

            Null Cases:

                 View February 04, 2012 Null case at KCLE
                 View February 08, 2012 null case at KCLE  
                 View February 11, 2012 Null case at KCLE 
                 View February 12, 2012 Null case at KCLE
                 View February 15, 2012 Null case at KCLE
                 View February 19, 2012 Null case at KCLE
                 View February 21, 2012 Null case at KCLE
                 View February 22, 2012 Null case at KCLE
                 View February 23, 2012 Null case at KCLE

     The following show the number of MOG "Moderate or Greater" (top) and Null (bottom) PIREPs and matches to PIREP icing classification for four icing algorithms with resulting PODY and PODn.

     The resulting statistics for the 75 MOG and Null categories are shown in the table above. Categories for atmospheric SLW production mechanism (left column) are loosely based on work done by Bernstein et al., (1997), which related aircraft icing to synoptic-scale weather conditions. The center block of columns shows total PIREPs for each mechanism and the corresponding number of cases matched correctly by each IH algorithm, followed by a summation row. PODY and PODN are calculated on these summed case numbers. The right hand block of columns is the same but for NIRSS cases at Cleveland, Ohio. The PING network was utilized to provide surface precipitation type for each case.

Sorted by Type:

•   Moderate or Greater PIREP cases
•   Null PIREPS

Summary 

     In-flight icing can be a significant hazard to aircraft and detecting and warning on its existence is a priority for the FAA. NCAR has been working since 2009 on an algorithm using polarized S-band NEXRAD weather radars, as well as continuing development with NASA of NIRSS. In this study, it was found that where there was detectable S-band signal above the noise threshold, operational NEXRADs had a very high icing detection rate over a wide variety of forcing mechanisms and surface precipitation types compared to icing PIREPs. There still remains a whole category of icing cases that may not be detectable by S-band weather radars, whose relative frequency should be determined in future studies. The National Severe Storms Laboratory, in collaboration with NCAR, is testing a new noise filter based on ρHV which aims to retain more of the low signal reflectivity areas. This product could significantly boost the IH ability to detect small-drop cases, at least in airport terminal areas within 15 km of the radar. Modules to detect high Zdr bands within precipitation and to detect negative Zdr in graupel will be tested and implemented in the upcoming year. There is also the possibility of a research flight campaign in 2014-2015 in the Great Lakes Region to further test the ground based remote sensing algorithms discussed within. Geographic diversity of icing across the US should also be pursued further.

Scott's To Do List:

IHL Project References

• Bernstein, B.C., F. McDonough, M.K. Politovich, B.G. Brown, T.P. Ratvasky, D.R. Miller, C.A. Wolff and G. Cunning, 2005: Current Icing Potential: Algorithm Description and Comparison with Aircraft Observations. J. Appl. Meteor.,44, pp. 969-986.
• Brunkow, D., Bringi, V. N., Kennedy, P, Rutledge, S., Chandrasekar, V., Mueller, E. and Bowie, R., 2000: “A description of the CSU--CHILL National Radar Facility”, J. Atmos. Ocean. Tech,17, Issue 12, pp. 1596-1608.
• Ellis, S.M., D.Serke, J. Hubbert, D. Albo, A. Weekley and M.K. Politovich, 2011: “In-flight icing detection using S-band dual-polarimetric weather radar data”, AMS 35^thConf. on Radar Meteorology, Pittsburgh, PA, 26-30 September. Available online.
• Ellis, S.M., D.Serke, J. Hubbert, D. Albo, A. Weekley and M.K. Politovich, 2012: “Towards the Detection of Aircraft Icing Conditions Using Operational Dual-polarimetric Radar”, 7^thEuropean Radar Conference on Radar in Meteorology and Hydrology, Toulouse, FR, 24-29 June, Available online.
• Hogg, D.C., F.O. Guiraud, J.B. Snider, M.T., Decker and E.R. Westwater, “A steerable dual-channel microwave radiometer for measurements of water vapor and liquid water in the troposphere”, 1983: J. Climate Appl. Meteor.,22, pp. 789-806.
• Hubbert, J., Ellis, S., Dixon, M. and Meymaris, G., 2010: “Modelling, error analysis and evaluation of dual-polarization variables obtained from simultaneous horizontal and vertical polarization transmit radar. Part II: modelling and antenna errors”, J. Atmos. Ocean. Tech.,27, pp.1583-1597.
• Hubbert, J., Ellis, S., Dixon, M. and Meymaris, G., 2010: “Modelling, error analysis and evaluation of dual-polarization variables obtained from simultaneous horizontal and vertical polarization transmit radar. Part II: experimental data”, J. Atmos. Ocean. Tech.,27, pp.1599-1607.
• Ikeda, K., Rasmussen, R., Brandes, E. and McDonough, F., 2008: “Freezing drizzle detection with WSR-88D radars”, J.Appl. Meteor. Climatol,48, pp. 41-60.
• Johnston, C., Serke, D., Adriaansen, D., Reehorst, A., Politovich, M. K., Wolff, C. and McDonough, F., 2011: “Comparison of in-situ, model and ground based in-flight icing severity”, AMS Preprint, Jan. 24-27, Seattle, WA.
• Plummer, D.M., S. Goeke, R.M. Rauber and L.DiGirolamo, 2010: “Discrimination of mixed-versus ice-phase clouds using dual-polarization radar with application to detection of aircraft icing regions”, J. Appl. Meteor. Clim.,49, pp. 920 – 935.
• Reehorst, A.L., Brinker, D.J., Ratvasky, T.P., 2005: “NASA Icing Remote Sensing System: comparisons from AIRS-II,” NASA/TM--2005-213592.
• Serke, D., J., Hubbert, S. Ellis, A. Reehorst, P. Kennedy, D. Albo, A. Weekley and M. Politovich, 2011: “The winter 2010 FRONT/NIRSS in-flight icing detection field campaign”, AMS 35^thConf. on Radar Meteorology, Pittsburgh, PA, 26-30 September, Available online.
• Serke, D., Reehorst, A., and Politovich, M., 2012: “Using Ka-band Doppler fall velocity spectra to enhance NASA's Icing Remote Sensing System”, AMS Annual Conference, New Orleans, LA, 23-26 January, Available online.
• Solheim, F., Godwin, J., Westwater, E., Han, Y., Keihm, S., Marsh, K., and Ware, R., 1998: “Radiometric profiling of temperature, water vapor and cloud liquid water using various inversion methods”, Radio Science,33, pp. 393-404.
• Vivekanandan, J., S.M. Ellis, R. Oye, D. S. Zrnic, A. V. Ryzhkov and J. Straka, 1999: “Cloud Microphysics Retrieval Using S-band Dual-Polarization Radar Measurements”, Bull. Amer. Meteor. Soc.,80, pp. 381-388.

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