Introduction to Global Aircraft Based Observations
Transcript of Introduction to Global Aircraft Based Observations
ABO WorkshopECMWF, Reading12th/13th February 2020
Steve Stringer,
E-ABO Programme Manager
Introduction to Global Aircraft Based Observations
Global ABO – We’ve come a long way!
Aircraft observations have been around for a long time…and were being routinely made before there were radiosondes
ADS-BADS-C
AMDARMode-S EHS/MRAR
Global ABO
…plus AIREPs, PIREPs, TAMDAR, AFIRS …plus UAVs & Research aircraft
Global ABO – Temperature & WindAMDAR
ADS-C
12 Programmes
40+ Airlines
Global ABO – AMDAR Temperature & Wind
• Australia • Canada• China• E-AMDAR• Hong Kong, China• Japan
• LATAM• Mexico• New Zealand• Korea• South Africa• USA
Aer Lingus Delta Air Lines NAV Canada
Air Canada Jazz Dragon Airlines Northwest Airlines
Aerolíneas Argentinas EasyJet Airline Novair Scandinavia
Aeromexico Eurowings Qantas Airways
Air France Federal Express Scandinavian Airlines
Air New Zealand Finnair Shandong Airlines
Air Nippon Airways Japan Airlines SkyTraders
Alaska Airlines JetConnect (Qantas) South African Airways
American Airlines Korean Air Southwest Airlines
Asiana Airlines LATAM Airlines Sunclass Airlines
Austrian Airways Lufthansa Cargo United Airlines
British Airways Lufthansa CityLine United Parcel Service
Cathay Pacific Lufthansa Germanwings
China Southern Airlines Lufthansa Passage
Global ABO – Temperature & Wind
Global ABO – Water Vapour
WVSS & TAMDAR WVSS & TAMDAR (exc. MDCRS)
WVSS TAMDAR
Global ABO – Turbulence & Icing
TAMDAR produces:• Temperature• Wind• Humidity• Turbulence • Icing
Global ABO: What is actually measured & reported by aircraft?
What is measured: Pressure
Pressure (and speed) is measured by standard aircraft sensors known as Pitot-static tubes
• Static pressure is used to calculate pressure altitude (PALT)
• Static pressure (normal air pressure) and dynamic pressure (caused by flight) can be used together to calculate the aircraft’s speed as a Mach number (M)
What is measured: Pressure (Altitude)
• Temperature is measured by a Total Air Temperature (TAT) probe
• Sensor faces into the airflow and brings air to a stop inside the sensor where its temperature is measured
What is measured: Temperature
This halting effect causes the air to warm. This warmer value is known as the Total Air Temperature (TAT)
This is then converted into Static Air Temperature (SAT) by onboard software, which is equivalent to the true external air temperature
What is measured: Temperature
What is measured: Temperature – linking to Mach number
Static Air Temperature (SAT) is a function of sensor probe and Mach Number (aircraft speed relative to the speed of sound).
Mach Number is derived from total and static pressures
What is measured: Wind Speed and Direction - Method
The measurement of the three-dimensional wind vector from an aircraft is a complicated problem!
Using the aircraft navigation system and the airspeed system (Pitot-static tubes) together with the TAT sensors, it is possible to estimate – to a high enough degree of accuracy:
• The velocity of the aircraft with respect to the ground below it
(Vg = ground speed)
• The velocity of the aircraft with respect to the air around it
(Va = airspeed).
V
Va
Wind Vector (V) is then given by: V = Vg – Va.
What is measured: Sensor Interdependencies
Observation reporting: On-board systems
Applies for AMDAR/ AIREP/ ADS-C• Not all Avionics systems
are the same!• Different manufacturers
& different versions• Downlink Formats are
standardised (ARP & AMDAR)
• Other parameters included with AMDAR message, e.g roll angle, to show aircraft is manoeuvering
Observation reporting: Downlinking
Monitoring & Metadata
Mode-S
E-ABO Regional requirements
EUCOS area: 70°W to 40°E; 10°N to 90°N
Observations: Spatial resolution: 250kmTemporal resolution: 3 hours
Quality: Maximum temperature RMSE ≤ 1.5 K
(≤ 1.0 K goal) Maximum wind RMSVD ≤ 5 m/s. (≤ 3.5m/s goal)• for E-ABO, these are monitored wrt
ECMWF Global model
In addition, some NMHSs (DWD, KNMI, MeteoFrance, MetO) have additional National requirements, which require additional national funding
Observations: Spatial resolution: <100km/ Every national airportTemporal resolution: 1 hourTimeliness: T+15 mins or less
Q
Questions?