Julie Haggerty NCAR

Rodney Potts BOM

The High Ice Water Content (HIWC) hazard to aviation

Experimental nowcasting products for avoidance of HIWC conditions

Engaging with potential users

Product evaluation in an operational setting

Exercise goals

Large concentrations of small ice crystals can exist in areas

of convective clouds with low radar reflectivity

Ice crystals stick to warm metal surfaces in jet engine low

pressure compressor

Over 150 Ice Crystal Icing events confirmed to date (Event locations provided by M. Bravin, Boeing, 2015)

◦ Ice accretes; accumulated ice can

block flow into engine core or shed

into high pressure compressor or

combustor

◦ Result may be power surge, power

loss, engine damage

Aircraft data systems may

also be affected by ingest of

ice crystals into inlets ◦ Result may be errors in

temperature, air speed, and angle

of attack

Engine modification

Detection of ice crystals by pilots’ weather radar

Identification of HIWC areas with standard meteorological data sets ◦ Products to enable avoidance of hazard

◦ Development efforts underway by multiple research teams

Uses operationally available data as input

Applies fuzzy logic methodology to blend input data Apply expert knowledge to create rule-based behavior

Membership functions characterize the relationship of each variable to the possibility of HIWC conditions

Blend data with adjustable weighting factors

Provides a 3-dimensional estimate of HIWC potential 0: minimum interest, no HIWC likely

1: maximum interest, high likelihood of HIWC

Currently uncalibrated

*Research sponsored by U.S. FAA

Operationally available data

Blend via algorithms using fuzzy logic rules/ membership functions Gridded field of potential for HIWC conditions

Three field campaigns ◦ 23 flights based in Darwin,

Australia

◦ 16 flights based in Cayenne, French Guiana

◦ 10 flights based in Florida, US

IWC Measurements ◦ In situ Isokinetic Probe

◦ Cloud radar retrievals of IWC profiles

Machine Learning Technique for Algorithm Tuning ◦ Data set partitioned into

Training and Verification subsets

HIWC Potential

PoD-yes: 77.3%

Misses: 22.7%

PoD-no: 79.4%

False Alarm Rate: 20.6%

ALPHA v2.1 Performance Statistics

Experimental

ALPHA available

in real-time over

U.S. since 2016

Informal

feedback

solicited from

small set of

users

Currently no

mechanism to

obtain structured

feedback on

utility and

performance or

quantitative data

for verification

Joint effort with Australian Bureau of Meteorology

(BOM), NCAR, and U.S. Federal Aviation

Administration (FAA)

Provide experimental HIWC products to aviation

industry stakeholders for a discrete time period

Qantas

Virgin Australia

Solicit feedback on product performance and

utility during convective season

Evaluate and modify ALPHA as indicated by user

experience

HIWC Nowcasting Trial Exercise

ALPHA

implemented over

northern Australia

and maritime

continent

Initial trial during

monsoon

convective

season, Jan-Mar

2018; second trial

in 2019

Monitor

performance

based on airline

feedback

HIWC Nowcasting Trial Exercise

ALPHA Domain

Radar Data Available

HIWC Nowcasting Trial:

Organizational Structure and Responsibilities

NCAR • Regional ALPHA

development • Implementation

on BOM server • Scientific and

technical support • Evaluate and

incorporate feedback to improve algorithms

BOM • Provide input data

• ACCESS • HIMAWARI-8 • Radar

• Host server • Prepare and

distribute products

• Coordinate and analyze feedback

Airlines • Access product and

integrate with other meteorological products

• Monitor areas identified as HIWC

• Pilot education on characteristics of HIWC in flight

• Note suspected encounters with HIWC

• Provide feedback

ALPHA

Development

Installation

& Testing

Product

Trial:

Phase I

Post-trial

Workshop

ALPHA

Modification

Installation

& Testing

Product

Trial:

Phase II

Final

Report

HIWC Nowcasting Trial Exercise: Schedule

2017 May Dec 2018 Jan Mar

2018 Jul Dec 2019 Jan Mar

HIWC Nowcasting Trial: Expected Outcomes

Provide the BOM with an experimental HIWC nowcasting

capability.

Provide NCAR and FAA with feedback on ALPHA

performance in a region with frequent convection and ICI

events.

Provide information to be used for further improvements to

ALPHA

Inform FAA and BOM decision on feasibility of a fully

operational HIWC nowcasting product.

Progress the development of an international capability for

HIWC detection and prediction that may be required by ICAO

in the future.

This research is in response to requirements and funding by the Federal Aviation Administration (FAA). The views expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.