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Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns

AMA-NASA Langley Research Center-Justin Strickland, Patricia Hunt
FAA William J. Hughes Technical Center-Christopher Dumont
Published 2019-06-10 by SAE International in United States
NASA and the FAA conducted two flight campaigns to quantify onboard weather radar measurements with in-situ measurements of high concentrations of ice crystals found in deep convective storms. The ultimate goal of this research was to improve the understanding of high ice water content (HIWC) and develop onboard weather radar processing techniques to detect regions of HIWC ahead of an aircraft to enable tactical avoidance of the potentially hazardous conditions. Both HIWC RADAR campaigns utilized the NASA DC-8 Airborne Science Laboratory equipped with a Honeywell RDR-4000 weather radar and in-situ microphysical instruments to characterize the ice crystal clouds. The purpose of this paper is to summarize how these campaigns were conducted and highlight key results.The first campaign was conducted in August 2015 with a base of operations in Ft. Lauderdale, Florida. Ten research flights were made into deep convective systems that included Mesoscale Convective Systems (MCS) near the Gulf of Mexico and Atlantic Ocean, and Tropical Storms Danny and Erika near the Caribbean Sea. The radar and in-situ measurements from these ten flights were analyzed…
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Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

NASA John Glenn Research Center-Peter M. Struk, Juan Agui, Thomas Ratvasky, Michael King
Ohio Aerospace Institute-Tadas Bartkus, Jen-Ching Tsao
Published 2019-06-10 by SAE International in United States
This paper describes an ice-crystal icing experiment conducted at the NASA Propulsion System Laboratory during June 2018. This test produced ice shape data on an airfoil for different test conditions similar to those inside the compressor region of a turbo-fan jet engine. Mixed-phase icing conditions were generated by partially freezing out a water spray using the relative humidity of flow as the primary parameter to control freeze-out. The paper presents the ice shape data and associated conditions which include pressure, velocity, temperature, humidity, total water content, melt ratio, and particle size distribution. The test featured a new instrument traversing system which allowed surveys of the flow and cloud. The purpose of this work was to provide experimental ice shape data and associated conditions to help develop and validate ice-crystal icing accretion models. The results support previous experimental observations of a minimum melt-ratio threshold for accretion to occur as well as the existence of a plateau region where the icing severity is high for a range of melt ratios. However, a maximum limit for melt ratio,…
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Analysis and Automated Detection of Ice Crystal Icing Conditions Using Geostationary Satellite Datasets and In Situ Ice Water Content Measurements

SAE International Journal of Advances and Current Practices in Mobility

Met Analytics, Inc.-J. Walter Strapp
NASA John Glenn Research Center-Thomas Ratvasky
  • Journal Article
  • 2019-01-1953
Published 2019-06-10 by SAE International in United States
Recent studies have found that high mass concentrations of ice particles in regions of deep convective storms can adversely impact aircraft engine and air probe (e.g. pitot tube and air temperature) performance. Radar reflectivity in these regions suggests that they are safe for aircraft penetration, yet high ice water content (HIWC) is still encountered. The aviation weather community seeks additional remote sensing methods for delineating where ice particle (or crystal) icing conditions are likely to occur, including products derived from geostationary (GEO) satellite imagery that is now available in near-real time at increasingly high spatio-temporal detail from the global GEO satellite constellation. A recent study using a large sample of co-located GEO satellite and in-situ isokinetic evaporator probe (IKP-2) total water content (TWC) datasets found that optically thick clouds with tops near to or above the tropopause in close proximity (≤ 40 km) to convective updrafts were most likely to contain high TWC (TWC ≥ 1 g m-3). These parameters are detected using automated algorithms and combined to generate a HIWC probability (PHIWC) product at…
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Radar Detection of High Concentrations of Ice Particles - Methodology and Preliminary Flight Test Results

AMA - NASA Langley Research Center-Justin Strickland, Patricia Hunt, George Switzer
Federal Aviation Administration-Christopher Dumont
Published 2019-06-10 by SAE International in United States
High Ice Water Content (HIWC) has been identified as a primary causal factor in numerous engine events over the past two decades. Previous attempts to develop a remote detection process utilizing modern commercial radars have failed to produce reliable results. This paper discusses the reasons for previous failures and describes a new technique that has shown very encouraging accuracy and range performance without the need for any modifications to industry’s current radar design(s). The performance of this new process was evaluated during the joint NASA/FAA HIWC RADAR II Flight Campaign in August of 2018. Results from that evaluation are discussed, along with the potential for commercial application, and development of minimum operational performance standards for future radar products.
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Naturally Aspirating Isokinetic Total Water Content Probe: Wind Tunnel Test Results and Design Modifications

NASA John Glenn Research Center-Thomas Ratvasky
National Research Council Canada-Craig Davison
Published 2011-06-13 by SAE International in United States
A total water content probe for flight- and ground-based testing is being completed. During operation across a range of altitudes and water content conditions, the probe has to maintain isokinetic flow, vaporize the solid and liquid water content and maintain the inlet ice free to ensure isokinetic flow. Despite achieving isokinetic operation, the collection efficiency of particles less than 30 μm can be less than 100%. A correlation of collection efficiency to Stokes number has been determined to correct the results for this effect. In preparation for flight testing an integrated data acquisition, control and power supply unit was developed and successfully tested. Results from testing at the NASA Glenn Icing Research Tunnel are presented covering both ice crystals and super-cooled liquid conditions. The results correspond well to previously published work and problems encountered during previous testing of this probe are shown to have been resolved.
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Detection of In-flight Icing Conditions by Radar over an Airport

Atmospheric and Oceanic Sciences, McGill University-Frédéric Fabry, Isztar Zawadzki
Cloud Physics Research Division, Meteorological Service of Canada-Stewart Cober, George Isaac
Published 2003-06-16 by SAE International in United States
Two sets of approaches to detect the presence of supercooled liquid water (SLW) over an airport area with radars are overviewed. The first set focuses on how scanning radars such as those existing in national networks might provide maps of icing likelihood and perhaps intensity over the approach area. The second set deals with the potential uses of dedicated low-cost vertically pointing radars located at the airport site itself to quantify amounts of supercooled cloud, drizzle, and rain over the airport.
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