Transcript Deutscher Wetterdienst Measurement Technology Humidity Measurements by Aircraft of the E-AMDAR Fleet TECO 2008 Axel Hoff Deutscher Wetterdienst Observing Networks and Data Offenbach am Main Germany.

Deutscher Wetterdienst
Measurement Technology
Humidity Measurements
by Aircraft of the E-AMDAR Fleet
TECO 2008
Axel Hoff
Deutscher Wetterdienst
Observing Networks and Data
Offenbach am Main
Germany
Deutscher Wetterdienst
Measurement Technology
ACARS
Aircraft
Communications
Addressing
and
Reporting
System
AMDAR =
Aircraft Meteorological Data Relay
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Measurement Technology
20 min after start
Enroute
Sampling rate = 7 min
Sampling rate = 50 s
Reports:
Descent
beginning at 18000 ft
• Aircraft Identification
• Date
Sampling rate = 10 s
until 150 s after start
• Time (UTC)
• Position
• Altitude (Pressure)
• Temperature
• Wind Speed
• Wind Direction
• Water Vapor
Mass Mixing Ratio
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Sampling rate = 40 s
Touch down
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Measurement Technology
EUMETNET AMDAR
(E-AMDAR)
Sampling Points
of 24 h
over Europe
BUFR:
DWD
(LH)
FM 42:
SMHI
Meteo France
UKMO
KNMI
(SAS)
(AF)
(BA)
(KLM)
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Measurement Technology
AMDAR in Numbers
(for 2007)
Activated Aircraft
Reports
per Day
DWD
289
21 000
E-AMDAR
600
35 000
2 800
250 000
AMDAR worldwide
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Humidity sensor enters the European AMDAR fleet
3 aircraft of the
Airbus A320 family
Typical daily flight program
over Europe:
• distance: 300 - 3000 km
• up to
6 ascents + descents
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Sensor
System
SEB (System Electronics Box)
SpectraSensors, WVSS-II Version 2006
• Infrared Absorption Spectrometer
2f method
Tunable Diode Laser
• Output:
Water Vapor Mass Mixing Ratio
Hoses for
connection
Air Sampler
with SEB
Air Sampler
Function
Air Sampler
Fuselage
Sampling Tube
24 cm
24 cm
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SEB
SEB
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Installation on the Aircraft
4.8 m
Exterior View
4 o‘Clock Position
Air Sampler
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Installation on the
Aircraft
Skin
Interior View
Outlet Hose,
Non-Heated
Inlet Hose,
Heated
Frame
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Measurement Technology
Cost Estimate for AMDAR Humidity Profiles
Costs per
Vertical Profile
(€)
AMDAR without humidity measurement
AMDAR, surcharge for humidity
Radiosonde + accessories (consumables only)
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6
30
> 200
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Measurement Technology
Results
of the Flight Operation
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Measurement Technology
Temperature
Dewpoint
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Measurement Technology
Observing Networks and Data – November 2008
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Measurement Technology
Observing Networks and Data – November 2008
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Measurement Technology
Verification
against
COSMO-EU
July 2008
12:00 UTC
EU4593
EU5331
EU6564
Bias (Model - Observation)
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RMS
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Measurement Technology
Verification
against
COSMO-EU
September 2008
12:00 UTC
EU4593
EU5331
EU6564
Bias (Model - Observation)
Observing Networks and Data – November 2008
RMSE
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Measurement Technology
RMSE
Mixing
Ratio
(g/kg)
Bias
Observing Networks and Data – November 2008
Deutscher Wetterdienst
Measurement Technology
RMSE
Mixing
Ratio
(g/kg)
Bias
Observing Networks and Data – November 2008
Deutscher Wetterdienst
Measurement Technology
RMSE
Mixing
Ratio
(g/kg)
Bias
Observing Networks and Data – November 2008
Deutscher Wetterdienst
Measurement Technology
Trial‘s Result of the WVSS-II Version 2006:
• Constant routine operation within E-AMDAR
• Relative Accuracy within ± 10 % (during the first weeks)
• Drift (because of missing Laser Burn-In time)
• After a few months of operation:
bias of partly 10 to 20 % Rel. Humidity
• Limit of detection ≈ 0.05 g/kg (80 ppmv)
 lower 2/3 of the Troposphere
• High RMSE because of limited coding
in the data link from aircraft to ground
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Consequences by the manufacturer SpectraSensors Inc.
due to the resuls of NOAA / NWS and E-AMDAR / DWD:
„Re-engineering“ → WVSS-II Version 2008
leading to
- stability in the electronics
- tightness of the Laser head
resulting in
- relative accuracy
within ± 5 %
- detection limit
< 0.015 g/kg (24 ppmv)
→ complete Troposphere
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Measurement Technology
Planings for further steps
• Replacement of the old (2006) WVSS-II units on the Airbus A319
• Separate test flights on research aircraft,
such as possibly the Airbus A340 (MOZAIC)
- intercomparison sensor on board
- WVSS-II
house-keeping data
- cyclic interchange:
aircraft ↔ laboratory
• Decision about
more sensors
• Format improvement
for data link
from aircraft to ground
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Measurement Technology
AMDAR, quo vadis
• Expansion and densification of the network on a global level:
- inclusion of more airlines,
- greater use of night-time starts and landings,
- optimizing of the data supply.
• Aircraft providing additional measurable variables
- humidity (to catch up with radiosondes),
-
E-AMDAR / BoM
NWS / NOAA
E-AMDAR
geometric altitude (GPS, GLONASS, GALILEO, ...),
air chemistry, aerosols,
turbulence,
icing.
• Correction methods for systematic error components.
• International standards for aircraft manufacturers:
- ex-works AMDAR configuration of the on-board software,
- ex-works mechanical and electrical precautions
for humidity sensor interfaces.
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WMO / E-AMDAR
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Measurement Technology
Questions or comments?
Observing Networks and Data – November 2008