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Nowcasting Development and Users’Need in Aviation

Ping-Wah Peter LIAviation Weather Services Branch, Hong Kong Observatory

Working Group in Nowcasting ResearchGeneva, WMO

8-10 February 2011

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Outline

� The challenge� MSTA objective� Guiding principles� MSTA initial concepts� Outstanding questions� Next Steps� Other special requirement

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The challenge

� ICAO Annex 3 stipulates MET Services� …in support of aerodrome operations

� Aerodrome Forecast (TAF)� Trend-type Landing Forecast (TREND)� Aerodrome Warnings

� …in support of FIR, regional, global operations� AIRMET/SIGMET� WAFC charts

� Most in highly-condensed, coded, textual formatCurrent Practice:

TAF VHHH 060500Z 0606/0712 27010KT 7000 FEW040 TX22/0607Z TX23/0707Z TN16/0623Z TEMPO 0606/0609 4000 HZ BECMG 0608/0610 09005KT BECMG 0703/0705 27010KT TEMPO 0704/0709 4000 HZ BECMG 0708/0710 09010KT=

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An aircraft report (An aircraft report ( 21/11/200621/11/2006))

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Weather radar showing intense Weather radar showing intense echoesechoes

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FTHK31 VHHH 081100 AAB TAF AMD VHHH 081608Z 0816/0918 24010KT 7000 FEW020 SCT060 TX33/0906Z TN26/0816Z TEMPO 0816/0819 08025G40KT 2000 TSRA +SHRA FEW008 SCT012CB BKN050 BECMG 0818/0820 30005KT TEMPO 0822/0908 4000 HZ SHRA TEMPO 0908/0912 36020G30KT 2000 TSRA +SHRA FEW008 SCT015CB BKN050 BECMG 0909/0911 VRB05KT=

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The challenge

� These Services do not meet the needs of today’s aircraft operators� Not specific enough� Nothing between aerodrome and FIR/global scale� No info on important parameters (location and movement

of convection, crosswind, headwind, winter conditions such as snow fall rate)

� The problem has been recognized by ICAO� “MET services required by ATM to optimize traffic flow in

the enroute and terminal areas”

� Various Member states are developing new MET services to address their needs

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What the WMO is doing� An expert team was established by the Commission for

Aeronautical Meteorology (CAeM) of the WMO at its 13th Session in 2006, and re-constituted at its 14th Session in 2010

� Name changed from New Terminal Forecast (NTF) to Meteorological Services for the Terminal Area (MSTA) to reflect that the new Services will supplement the TAF, not replace it

� Supported by a Task Team on User Needs (TT-UN) to liaise with ICAO groups and aviation stakeholders � Aerodrome Meteorological Observation and Forecast Study

Group (AMOFSG) and its Ad Hoc Working Group� Air Traffic Management Requirements and Performance Panel

(ATMRPP)� IFALPA, IFATCA, IATA, etc.

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MSTA objective� … to address these new and evolving ATM user needs and

to avoid the costly parallel development of similar weather products of varying and confusing data formats

� … to develop a detailed MSTA proposal, supported by ICAO and the aviation user communities, ready for endorsement by the next Conjoint ICAO MET/AIM Divisional Meeting/WMO CAeM Session (currently scheduled for 2014) and reflected in ICAO Annex 3 (in 2016)

� Focussing effort on a particular need: the terminal area

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Guiding principles (1)

� For effective CDM (Collaborative Decision Making), the need to have a common picture

� Ease of use (“high glance value”) is paramount� Others (States, organizations) are working on

creating the databases, including NextGen Wx and SESAR. MSTA’s role is to define the service that will be driven by the data

� The general approach is nowcasting and NWP � However, a key role for the human in the

process… do QC, provide interpretation. A need to focus human intervention where it’s most effective

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Guiding principles (2)� Follow needs as identified by ICAO

� including elements, type of guidance (deterministic or probabilistic), attainable accuracy

� Have some questions re the ability to meet some of the targets

� Go beyond basic MET parameters to also consider their impact on ATM; i.e. bridge the gap, e.g.� Support to the determination of the active runway� Guidance for whether flights need to change the route

� Focus on operations in and around aerodromes, including airport operations, e.g. de-icing, runway maintenance, ramp operations

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What will it be

� A web-based graphical service� Fed by a database that will support other services such

as charts and a simplified version (text or object) for uplink to the cockpit

� The gridded/object data would be available for direct integration into users’ decision-support systems (DSTs)

� Integrate the most important info in an easy-to-use fashion, and colour-coded � Red : High impact on ATFM (action recommended)� Yellow : Possible impact to ATFM (manageable)� Green (Blue?) : Chance of impact is low but cannot be

excluded

� Detailed weather scenario/conditions/threshold determined by MET Authority and user

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What will it be� A "recommended practice“, not a regulatory

service; i.e. optional for a State to offer this service, but if it does, then it will define “how”

� A flexible framework…. focussing on a few basic parameters now (convection, winds, low visibility, winter weather)

� Expandable to include other parameters as techniques become available

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MSTA timeframe� Three timeframes (3-tier) to support differing needs

� Nowcast (0 to 1-2 hours)� High-resolution, rapid update� Supports tactical decision-making

� Short-term forecast (up to 6 hours)� Lower resolution, covers greater area� Supports tactical decision-making

� Outlook (up to 2 days ahead)� Even coarser resolution� Supports pre-tactical (or strategic) decision-making

15

nowcasting

blending with NWP

NWP

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“Live” demo of sample Integrated Display available at : http://www.msta.weather.gov.hk/ntf_interface/ntf_interface.phtml

MSTA initial concept on convection (nowcast)

TAF VHHH 022300Z 0300/0406 8000 FEW020 SCT040 TX28/0306Z TN22/0223Z TEMPO 0305/0307 2000 TSRA +SHRA FEW008 SCT012CB=

Significant weather forecast for the next 24 hours (0306-0406 UTC)Intense thunderstorms and CB associated with a trough of low pressure will move northeast away from NTF region gradually within the next 6 hours. Visibility will drop to around 1500m in heavy showers. There will be high chance of gusts (80%) reaching 40 knots at VHHH during 0306-0309 UTC

Outlook for 24-48 hours (0406 - 0506 UTC)Typhoon Ketsana is expected to enter the South China Sea. Embedded CB and isolated thunderstorms will start to affect the southeastern part of NTF region from around 0406-0412 UTC. The chance of northerly crosswinds reaching 20 kt withsignificant low level turbulence will become medium to high (60-80%) at VHHH during 0418-0506 UTC.

TAF

Textual description

tabular

graphics

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MSTA initial concept on convection (Short Term Forecast)

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MSTA initial concept on convection (outlook)

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Japanese Met Agency initiative (Alert Metric)

MDT or HVY

>= 1cm/h

Snow-fall rate

TS in TAF

Blue

TS in vcnty

>=20, MDT to HVY

>=25>=30, gust to >=50

Yellow

>=30 at sfc. >=50 blw 5000

TS over-head

<200 ft<500m>=25, MDT to HVY

>=30>=40Red

Wind shear

Convection

CIGVsby… with pcpn

Cross-wind comp

Wind

Criteria are terminal specific

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Japanese Met Agency initiative

Tabular format

sample

Graphical format (sample)

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Automated Thunderstorm Alert Service (Australia)

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International Trend

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Météo-France Thunderstorm detection and forecast for Air Traffic ControlApplication de Signalisation et Prévision des Orages pour le Contrôle Aérien (ASPOC)

• Convection monitoring based on weather radar and lightning data

• 4 intensity (dBZ) levels relevant to ATC operations.

• 30-min forecast

• Trial ASPOC-3D, based on wx radar, lightning data and satellite imagery (cloud top, Zmax)

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International Trend

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MIT Lincoln Lab Route Availability Planning Tool (R APT)MIT Lincoln Lab Route Availability Planning Tool (R APT)

• Operational at New York. Integrated into FAA Integrated Terminal Weather System (ITWS)

• An automated tool intended to help ATC and airline dispatchers determine the specific departure routes and departure times that will be affected by significant convective weather

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International Trend

TAF VHHH 141700Z 1418/1524 12010KT 7000 FEW010 SCT025 BKN060 TX29/1506Z TN24/1422Z TEMPO 1418/1421 VRB20G30KT 2500 TSRA +SHRA FEW008 SCT012CB BKN040 TEMPO 1421/1503 4000 SHRA=

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Validation and Verification (V&V) process

� People are most comfortable with “deterministic”answers (i.e. yes/no, specific values). However, people also request uncertainty information at times

� When predicting the occurrence of a thunderstorm at a specific point (a specific circle of 5 km radius), skill currently is limited to about 30 minutes

� Thus longer-term predictions need to be presented using a larger circle, reducing the accuracy targets, or taking a different approach (i.e. probabilistic)

� A challenge to create probabilistic guidance that’s meaningful.

� Also the need to incorporate a measure of confidence in the forecast

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Outstanding questions� A consensus for the need for probabilistic

forecasts� how to generate and encompass this information such

that it fulfils user needs and is used appropriately?

� The new MET service has to be supported by a well documented and transparent validation and verification (V&V) process.

� What relevant verification metrics to be used to include the user perspectives in the V&V process?

� How to define the operationally desirable accuracy of forecasts based on user’s perspective, and take into account the current/potential technological advancements in the next decade

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MET/ATM TF2Fukuoka, Japan, Jan 2011

� Development of probabilistic forecasts� Use of probabilistic forecasts in risk matrices may be considered to

meet user needs. On the other hand, development of probabilisticforecasts should take into consideration the currently achievable scientific and technological capabilities, the existing limitations and constraints such as limited predictability of convective activities in the very short range

� Verification and validation of forecast accuracy from users’perspective� Time-success diagram that can be constructed based on past

performance of the system. to provide a “tolerance limit” that defines what can be considered acceptable, and based on these definitions of a “hit”, a diagram can be constructed that allows to determine the likely lead time or any desired threshold of success

� “achievable accuracy at the typical time horizon”� Translating weather products to user impacts

� scenario based (i.e. include weather elements and whether such weather element will reach certain threshold/criteria which correlates to impact. The detailed criteria and weather element to be included is to be determined as agreed between MET authority and user

� Where to provide the necessary standards and guidance material for MSTA

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What WGNR can contribute

� Probabilistic Nowcast/forecast (PNC) research (0-6hr)� Ensemble tracking approach?� Tuning the parameters in numerical model?� Various blending extrapolation with high

resolution NWP?� Linking the PNC with impacts to aircraft

operations?� Verification & Validation studies at airports?

� Collaboration with CAeM on MSTA?

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MSTA website

Prototypes and questionnaire to collect feedback

http://msta.weather.gov.hk/

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Sample Show Case #1:HKO Advanced Aviation Nowcasting System (AANS)

in Support of Air Traffic Management by Blending Radar Nowcasting Data with NWP Forecast

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WMO/CAeM New Terminal Weather Forecast (NTF)

� Convective Products under development (3-tiers):� Nowcast (0-1hr)� Short-term (1-6hr)� Outlook (6 hr – 1 or 2

days)

http://ntwf.weather.gov.hk/

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Radar-based TS nowcasting System - Aviation Thunderstorm Nowcasting System (ATNS) for

tactical flight (0-1 hr) planning

Trial product has been under testing by local ATC & ATMD since 2009

Way-points

Select REF, TOP, MAX, VIL

Choose range circles

Storm intensity –radar 3km REF

Animation control

Select day time

Forecast time series at way-points

Cursor values

Choose routes and way-points

zoom/pan overlaid on googlemap

Time series forecasts of thunderstorm intensities at specific locations

Colored gridded radar reflectivity

Flight route

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ATNS on AMIDS

http://192.168.9.2/metcond/sig_conv_mf/sig_convection.phtmlhttp://al-nowcast.weather.gov.hk/main/com.swf

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3 km TREC wind of a heavy(>30mm/hr) rainstorm 23 UTC 9 August 2002

3 km TREC wind of Typhoon Maria31 August 2000

Stronger to the right, weaker to the left

50km/hr SW’lies with some embedding short waves

TREC (Tracking Radar Echoes by Correlation)

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� Intelligently blending radar-based nowcast with NWP forecasts

Nowcast High resolution NWP

extrapolation effective in advective cases; dissipative cases

effective in nonlinear moving; rapidly changing cases

high resolution, rapidly updatedseamless short-term convective forecast

Short -term convective forecast (0 -6 hr) –Advanced Aviation Nowcasting System

(AANS)

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Extending ATNS to 6 hr using modified Semi-Lagrangian Advection� Robert scheme (3 iterations)� Bi-cubic Lagrangian interpolation� Flux limiter (local max, min constraint)� One-way nested

� resolution 1.1km -> 0.5km

� Less dispersive� Circulation preserved

TREC wind Forecast reflectivity – TREC windUp to 6 hr (6-min interval)

0=∂∂+

∂∂=

x

Z

t

Z

dt

dZu

Forecast reflectivity – pure rotationUp to 6 hr (6-min interval)

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AANS

� Nowcasting component – extended-ATNS� 0 - 6 hr QPF by extending the linear extrapolation of radar

echoes

� NWP component – Non-hydrostatic Model (NHM)� 0 – 6 hr QPF by non-hydrostatic numerical modelling

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Non-hydrostatic Model (NHM) (adapted from JMA)

• 141x121 grids (5km)• 60 level• LAPS analysis adapted from NOAA/GSD

� Fully compressible� prognostic:

� u, v, w, p, θ, qv, qc, qr, qi, qs, qg

� Data ingested:� Doppler radar reflectivity & wind� GPS/PWV� wind profiler� satellite imageries� AWS …� TREC winds

� 12 hours forecasts updated every hour

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Special Features

� (i) phase correction: to tackle the problem of spatio-temporal errors in the model precipitation forecast using variational technique

� (ii) calibration of intensity of model QPF: correction of the intensity of model precipitation based on radar-based quantitative precipitation estimate (QPE), and

� (iii) blending of calibrated model QPF with the radar nowcast, with larger weighting assigned to the nowcast component at short lead times and increasing weighting to the NWPcomponent as lead time increases to 6 hours.

� (iv) converting precipitation back to reflectivity based on the latest Z-R relation

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NHMATNS QPFtwQPFtwtQPF ×+×−= )())(1()(

α, β determined dynamically by past performance

Blending extended-ATNS with NHM forecasts

{ })]93(tanh[12

)( −+

−+= TTw γαβα

α

βadjustment

1. NHM rain pattern adjustment –translation, rotation, deformation

2. Dynamical blending –hyperbolic function with varying end points

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Extended-ATNS AANS Radar QPE

T+1hr

T+2hr

T+3hr

Not sa

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AANS Radar QPE

T+4hr

T+5hr

T+6hr

Extended-ATNS

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00.1

0.20.30.40.5

0.60.70.80.9

1

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0

Forecast time (hour)

PO

D

ATNS AANS

00.1

0.20.3

0.40.50.6

0.70.8

0.9

1

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0

Forecast time (hour)

CSI

ATNS AANS

Performance of the extended-ATNS and AANS forecasts upto 6 hours ahead.

� AANS has a higher POD and CSI than the extended-ATNS beginning after 1-hr forecast time

� While the POD and CSI of the ATNS drops after 1-hr forecast time, the POD and CSI of AANS maintains at rather stable level until 5-hr forecast time

0.10.1

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Sample Show Case #2:Sample Show Case #2:HKO HKO Airport Thunderstorm and Airport Thunderstorm and

Lightning Alerting System (ATLAS)Lightning Alerting System (ATLAS)

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The Impact of Lightning Warning to the Operations of the Hong Kong International Airport

REDRED Lightning AlertLightning Alert

AMBERAMBER Lightning AlertLightning Alert

• All ground operations have to stop and take measures to protect against lightning strikes

• Re-fueling, embarkment /disembarkment, baggage/cargo handling would be delayed

-> major disruption to airport operations

Dissemination to users

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HKO Airport Thunderstorm and Lightning Alerting System (ATLAS)

� HKO Lightning Location Information System (LLIS) Cloud-to-Ground (CG) lightning data

� HKO Weather Radar data

HKO Doppler Weather Radars

Lightning Detector

HK-GD-MC Lightning Detection Network

Tai Mo ShanRadar

Tate’s CairnRadar

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Weather Radar (SWIRLS)Thunderstorm movement

LLIS network –Cloud-to-Ground (CG) lightning location

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ATLAS RED and AMBER Lightning Alerting Areas (HKIA 1km1km & 55kmkm Regions)

AMBERAMBER

REDRED

Lightning Alert

1km

5km

REDRED

AMBERAMBER

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28 Jul 2010 14:00 – 18:00

Longest RED Alert : 164 min, 14:42 - 17:25Total CG strike : 287 in 4 hours BlackBlack Rainstorm

Warning in force

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8 Sep 2010 23:30 –9 Sep 2010 02:30

2nd longest RED Alert : 93 min, 23:55 - 01:27Total CG strikes : 1028 in 3 hours (highest in record)

REDRED Rainstorm Warning in force

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Airport Thunderstorm and Lightning Alerting System (ATLAS)

� 20100728\atlas_selected_showcase_0728.html

� 20100908\atlas_selected_showcase_0908.html

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Time-lagged ensemble

score >=N, RED (e.g., N=20)score >=1, AMBERotherwise, GREEN

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Airport Lightning Warning Lights and Siren

ALWS

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Dedicated Web Site (AMIDS) for Airport Users

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Webpage and Mobile Platform

iPhone

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Real-time Verification System -Digital and Image Database

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THANK YOU