Observations From the Global AMDAR Programme

Presentation to

WMO TECO-2006 4-6 December 2006

by

Michael BerechreeTechnical Coordinator, WMO AMDAR Panel

System Description

Aircraft Meteorological DAta RelayAMDAR =

AMDAR is:

• A fully automated upper air observing system;

• High quality upper air observations of wind speed and direction, temperature, and sometimes turbulence and humidity;

• Available from many existing commercial, private and military aircraft;

System Description

=FITTED WITH EXISTING SENSORS

+ AVIONICS HARDWARE

+ AVIONICS SOFTWARE

+ COMMUNICATIONS

AMDAR SOFTWARE+ AMDAR uses existing aircraft and airline infrastructure:

• Wind, temperature and turbulence plus height (pressure), time and position;

• Onboard avionics and communications hardware and software; and

• Aircraft Communications And Reporting System (ACARS). Global services are provided by ARINC and SITA.

AMDAR System StructureAMDAR System StructureOperational, Reporting, Monitoring & FeedbackOperational, Reporting, Monitoring & Feedback

GTS

NMS

QEv Centre

Ground-basedData Processing

System(s)

RegionalData Optimising

Centre

FlightControl

SITA/ARINCNetwork

AirlinesUplinkingSystems

Co-ordinator

System Description

Data RequirementsDesirable Horizontal Spatial and Temporal Density:

1 profile on 250 km grid at 3 hourly intervals

Element Unit Range Outputresolution

Desiredaccuracy

PressureAltitude

Foot (ft) -1000 to 50000 10 100(1)

Static AirTemperature

oC -99 to 99 0.1 0.5(2)

WindDirection

O from true N 1 to 360 1 Note (2,3)

Wind Speed Knot (kt) 0 to 800 1 Note (2,3)Latitude Degree:minute 90:00S to 90:00N 1.0min Note (4)Longitude Degree:minute 180:00E to

180:00W1.0min Note (4)

Time (UTC) Hour:Minute:Second

00:00:00 to23:59:59

1 min 1s

Notes:

(1) required to preserve temperature accuracy(2) WMO requirement for NWP in troposphere(3) 2ms-1 (4kt) vector error(4) 5Nm equivalent (specified for ASDAR)

BASIC Data

Element Unit Range Output

resolution Desired accuracy

Maximum wind kt 0 to 800 1 4 Turbulence (g) g (4) -3 to 6 0.1 0.15(1) Turbulence(DEVG) ms-1 0 to 20 0.25 0.5(1) Turbulence(EDR) m2/3s-1 0 to 1 0.05 0.1(1) Humidity(RH) % 0 to 100 1 5(2) Humidity (dew pt) oC -99 to +49 0.1 Note 5 Humidity(mixing ratio)

gram/kg 0 to 100 0.001 1:103

(measurement)(3) Notes: (1) Determined by output categories required (2) WMO requirement for NWP in troposphere (3) To meet stratospheric humidity requirement (4) Acceleration due to gravity. ‘Zero’ reference on aircraft is usually +1. (5) Equivalent to 5% RH error.

Additional Data

Data Requirements

Mandatory and Optional Reported Elements

Element Mandatory/Optional Requires Additional (M/O) Onboard Processing

Aircraft identifier MPhase of flight MLatitude MLongitude MDay & time of observation MPressure altitude MStatic air temperature MWind direction MWind speed MMaximum wind MRoll & pitch angle flag M YESHumidity O YESTurbulence O YESIcing O YES

• AMDAR data have similar accuracy to that of radiosonde data and can be used in the same manner. A typical AMDAR vertical sounding of temperature and wind produces a profile that is typically less than 1% of the cost of a radiosonde profile.

• To provide data from data sparse areas around the world to improve local forecasts and to contribute to the WMO World Weather Watch Global Observing System; and

• For forecast verification;

• To meet the NWP community’s requirement for greater quantities and improved coverage of relevant upper air data;

Why is AMDAR Data Needed?

Why is AMDAR Data Needed?

AMDAR is particularly useful for now-casting situations where conditions are changing rapidly and are therefore of special use to the aviation industry. Such applications include:

Surface and upper air forecasts of wind and temperature;

Thunderstorm genesis, location and severity;

Wind-shear location and intensity e.g. dangerous low-level jets;

Low cloud and fog formation, location and duration;

Turbulence location and intensity; and

Why is AMDAR Data Needed?

AMDAR data significantly improved NWP wind forecasts.

• For example, 3-hour wind forecast error was reduced by 40% with an overall improvement of 11%;

• 12-hour wind forecasts of winds improved by 5%;

• Impacts of these improved wind forecasts are better en-route and terminal management of aircraft and therefore leads to subsequent financial savings gained by the airlines; and

The benefits of AMDAR data are global and large for forecasts out to 48 hour.Why is AMDAR Data Needed?

The benefits of AMDAR data are global and large for forecasts out to 48 hour.Why is AMDAR Data Needed?

Over 200,000 high quality observations per day being exchanged on the GTSOver 2,800 reporting aircraft world wide

Growth in AMDAR data

Courtesy NOAA ESRL/GSD

24 Hour AMDAR Coverage30 November 2006

Courtesy NOAA ESRL/GSD

24 Hour AMDAR Profiles30 November 2006

Distribution map of the average number of aircraft reports decoded per 24-hour periods in 10 deg. lat-lon boxes. Courtesy Environment Canada.

Data Availability

Courtesy NOAA ESRL/GSD

AMDAR Temperature and Wind Profiles

Mean Temperature Bias in Tenths Deg. C. - E-AMDAR Aircraft Sept. 2006

-20

-15

-10

-5

0

5

10

15

20

EU0002

EU0051

EU0081

EU0201

EU0263

EU0310

EU0354

EU0405

EU0456

EU0493

EU0620

EU0807

EU0999

EU1247

EU1346

EU1532

EU1771

EU2043

EU2247

EU2405

EU2630

EU2800

EU2978

EU3102

EU3257

EU3362

EU3514

EU3670

EU3768

EU3908

EU4075

EU4278

EU4473

EU4589

EU4721

EU4976

EU5349

EU5544

EU5830

EU6258

EU6435

EU6900

EU7314

EU7643

EU7910

EU8891

EU9680

• High quality AMDAR data is suitable for use in all operational meteorological applications.

• Quality of observations received from each reporting aircraft is routinely monitored by regional and global centres.

• The NCEP is the WMO designated lead centre for monitoring aircraft observations.

• Data quality of data from most large jet transports is high while the quality of similar data derived from many smaller regional and commuter aircraft is often not suitable for meteorological use.

Data quality from CRJ passenger aircraft (bias based on Numerical Model output) - Courtesy: Meteorological Service of Canada

Monthly mean temperature bias of all European aircraft that reported in September 2006.

Data Quality

Data Quality

Frequency distribution of the mean temperature difference (OBS–Background)KNMI QEV Report – January – March 2004

Data Quality

Frequency distribution of the mean wind speed difference (OBS–Background)KNMI QEV Report – January – March 2004

AMDAR Humidity Measurement

Air Sampler

24 cm

SEB

Cylindrical Sampling Tube

Sensor System

SEB (System Electronics Box)

Air Sampler

Hoses (Heated and Non-Heated) for Interconnection Air Sampler - SEB

SpectraSensors, WVSS-II

• Near-Infrared Absorption Spectrometer Based on Tunable Diode Laser

• Heated Inlet Hose • Output:

Water Vapor Mass Mixing Ratio

SEB

FWD

Hose, Heated

Hose, Non-Heated

Skin

Air Sampler

Frame

Air Sampler

AMDAR Humidity Measurement

AMDAR data as per ARINC 620v4 Supplement 5

SEB

Probe

Hoses

28 VDC

ARINC bus 429

ATC

AM

DA

R

AO

CAir Traffic Service Unit

VHFHF

SATCOM

Flight Management System

Aircraft Interface

Host Platform

Hardware

ATC

Wea

ther

AO

C

WVSS-II

Step 1

Step 2

Airbus Solution for AMDAR

AMDAR Humidity Measurement

Recent comparison of WVSS-2 Water Vapour Profile and Radiosonde profile, November 2006

Courtesy NOAA ESRL/GSD

AMDAR Humidity Measurement

Relative Humidity differences between WVSS-II and Radiosondes

for 2-week test period

Tests have shown that WVSS-II water vapour data:

- are comparable to radiosonde moisture data;

- can be easily obtained in otherwise data sparse areas;

- profiles are observed at airports where aviation forecasters need them the most; and

- costs are substantially less than traditional moisture profiles from radiosondes.

The AMDAR Panel can help with organising regional or national AMDAR programmes by:

• Working with the NMHS to evaluate the potential for developing a national AMDAR program;

• Assisting with technical support and training;

• Providing technical material and manuals needed to establish a National or Regional AMDAR program; and

• Working with the NMHS and the airline to create the necessary documents and infrastructure agreements.

For More Information: http://www.wmo.int/web/aom/amprog/amprog.html/

Developing Regional or National AMDAR Programmes

Distribution map of the average number of aircraft reports decoded per 24-hour periods in 10 deg. lat-lon boxes. Courtesy Environment Canada.

Data Availability