Document
COMPARISON OF IN-SITU, MODEL AND GROUND BASED IN-FLIGHT ICING SEVERITY
A A A B A A A David J. Serke Christopher J. Johnston Daniel R. Adriaansen Andrew L. Reehorst Marcia K. Politovich Cory A. Wolff Frank McDonough A
National Center for Atmospheric Research - Boulder, Colorado
NCAR
B National Center for Atmospheric Research
NASA Glenn Research Center - Cleveland, Ohio National Aeronautics and Space Administration
NASA Icing Remote Sensing System
Pilot Reports
Overview
• In-flight icing (IFI) is a signficant hazard • A PIREP is a report of actual weather conditions encountered by an aircraft in flight. In this Integrates 3 vertically pointing sensors: These three sensors utilize the derived for the aviation industry.
study PIREPs are considered as the “truth” dataset.
integrated liquid water (ILW), radar • IFI occurs when supercooled liquid water • PIREPs can sometimes be inaccurate due to time lags before the pilot reports the observed 1. Multichannel microwave radiometer reflectivity, temperature profile, and cloud top (SLW) comes in contact with, and freezes to, icing condition, and whether he or she reports the correct altitude and location 2. Vaisala laser ceilometer and base heights to depict the presence of in- the leading surfaces of an aircraft.
3. Metek Ka-Band radar Time Pilot Reported flight icing in the atmopshere.
Flight Level • Significantly alters aircraft aerodynamic
Looks into and through cloud to find icing hazard
properties: - Increases the amount of drag on an aircraft - Reduces the lift Icing Type and Severity • The objective of this study is to examine how • Currently there are two systems that are the testbed NIRSS icing severity product and being developed for the detection of in-
Findings
the operational CIP severity product compare flight icing: to PIREPs of icing severity, and how the -NASA Icing Remote Sensing System Sample single day comparison (PIREP severity and height are red numbers): NIRSS and CIP compare to each other.
(NIRSS) Severe -Current Icing Product (CIP) Moderate Light NIRSS Trace kft No-Icing
Methodology
Severe Moderate • A three year database of CIP, NIRSS and PIREP data which concentrates on winter Light periods from early November to late March of the years 2008 through 2010 was compiled.
CIP Trace kft No-Icing • 917 PIREPS were detected within 40 km horizontal distance from the NIRSS system location near Cleveland-Hopkins International Airport in Cleveland, Ohio.
Full 3-year comparison: • CIP products were produced for the closest 20 by 20 kilometer RUC horizontal gridpoint
Current Icing Product
CIP versus PIREP icing severity: 8 0 0 0 0 0 0 0 0 0 to the NIRSS, and relevant icing severity values were extracted at the time of each icing • PODy = 0.90, PODn=0.29 7 1 1 0 5 0 4 0 0 0 PIREP.
• severity category correlation 0.21 6 4 0 0 1 1 1 0 0 0 Employs: • Warn volume 34% C 5 5 10 0 21 7 13 0 0 3 • Analysis occurred from the ground level to ~30,000 ft. For this study, a PIREP reported I 4 13 0 78 20 43 0 0 0 1. Visible and infrared satellite imagery over a range of heights is treated as multiple PIREPs spread over 1000 foot increments.
To produce a gridded, hourly, 3 P 3 22 14 0 94 20 35 0 0 0 2. Radar reflectivity (composite only) Dimensional representation of 2 32 12 1 97 13 40 0 0 0 3. Lightning reports Icing threat icing probability and severity. 1 38 23 0 92 6 7 0 0 0 Find PIREP and altitude between ground level & 30,000 feet 4. PIlot REPorts (PIREPs) 0 47 4 0 47 0 22 4 0 0 5. Ground observations (METARs) 0 1 2 3 4 5 6 7 8 6. Rapid Update Cycle (RUC) model variables PIREP Vertically search upwards and downwards through troposphere for nearest icing severity threat 8 0 0 0 0 0 0 0 0 0 PIREP
Does NOT look into cloud to find icing hazard
N 7 0 0 0 13 0 0 0 0 0 I 6 1 1 0 18 4 29 0 0 0 NIRSS versus PIREP icing severity: Complete temporal and spatial matching for all PIREPs R 5 1 7 0 28 8 23 0 0 0 Icing threat • PODy = 0.78, PODn=0.71 S 1 5 0 46 7 15 0 0 0 • severity category correlation 0.35 S 3 6 18 0 95 18 22 0 0 0 • Warn volume 13% 2 9 20 0 71 3 28 0 0 1
Acknowledgements
* Prototype NIRSS does nearly as 1 28 10 1 71 12 14 0 0 2 good as operational CIP at icing and 0 115 19 0 93 16 34 4 0 0 much better at non-icing detection in 0 1 2 3 4 5 6 7 8 This research is supported by the NASA Aviation Safety Program under the Atmospheric PIREP Environment Safety Technologies (AEST) project. The views expressed are those of the authors and do not necessarily represent the official policy or position of the NASA.