EULINOX

Aircraft Instrumentation

Lightning Location

Radar


 

Falcon Measurements for EULINOX

Personal involved:

Laurent Boutin (DLR-OP) 
Reinhold Busen (DLR-OP) 
Christian Feigl (DLR-OP) 
Christoph Gerbig (FZ-Juelich) 
Heidi Huntrieser (DLR-OP) 
Rainer Marquardt (DLR-OP) 
Andreas Petzold (DLR-OP) 
Paul Stock (DLR-OP)

 

CO2-O3 rack Positions of the measuring systems in the Falcon

O3 (DLR-OP):

Ozone is measured with an UV absorption photometer. The instrument consists of an UV-lamp (temperature-controlled mercury lamp), a cylinder-formed absorption chamber (irradiated by the UV-lamp), and an UV-Photometer for detection of the transmitted light in the chamber. A three-way valve direct the sample air flow (controlled by a membrane pump) alternately to the absorption chamber and to a scrubber. After the sample air has been scrubbed of ozone it is also directed into the absorption chamber. The difference between the light transmission from the sample air with and without ozone corresponds to the ozone particle number density. From this number density the concentration (volume mixing ratio) of ozone can be calculated by including continuous measurements of pressure and temperature.
 
References

Schlager, H., P. Konopka, P. Schulte, U. Schumann, H. Ziereis, F. Arnold, M. Klemm, D. E. Hagen, P. D. Whitefield, and J. Ovarlez, 1997: In situ observations of air traffic emission signatures in the North Atlantic flight corridor, J. Geophys. Res., 102, D9, 10739-10750.

Ozon UV absorption photometer. Flow scheme

CO2 (DLR-OP):

The CO2 measuring system consists mainly of a membrane pump, a differential non dispersive infrared (NDIR) analyser (BINOSR 1.1) and a pressure control unit. A reference gas (CO2 in synthetic air) with a known CO2 mixing ratio is directed by a pressure controller and mass flow controller through a filter (0.2 mm Polytetrafluorethylen PTFE) into the reference chamber. The sample air is also pumped through the same kind of filter and then directed into the measuring chamber. The analyser uses the specific absorption of infrared light at 4.36 mm by CO2 to estimate the CO2 volume mixing ratio. To prevent measuring errors caused by pressure fluctuations the reference and sample air pressure is kept constant at 1.1 bar behind the chambers.

References

Schulte, P., H. Schlager, H. Ziereis, U. Schumann, S. L. Baughcum, and F. Deidewig, 1997: NOx emission indices of subsonic long-range jet aircraft at cruise altitude: In situ measurements and predictions, J. Geophys. Res., 102, D17, 21431-21442.

Stock, P., 1998: Flugzeuggetragene Kohlendioxidmessungen: Laboruntersuchungen und Messungen über dem Nordatlantik, Diplomarbeit Fachhochschule Muenchen (Physikalische Technik), 75 pp.

CO2 measuring system. Flow scheme

NO/NO2/NOy (DLR-OP):

References

Schlager, H., P. Konopka, P. Schulte, U. Schumann, H. Ziereis, F. Arnold, M. Klemm, D. E. Hagen, P. D. Whitefield, and J. Ovarlez, 1997: In situ observations of air traffic emission signatures in the North Atlantic flight corridor, J. Geophys. Res., 102, D9, 10739-10750.

Schulte, P., H. Schlager, H. Ziereis, U. Schumann, S. L. Baughcum, and F. Deidewig, 1997: NOx emission indices of subsonic long-range jet aircraft at cruise altitude: In situ measurements and predictions, J. Geophys. Res., 102, D17, 21431-21442.

CO (FZ-Juelich):

The CO measurements are made with a fast response resonance fluorescence instrument, which has been developed at FZJ and which has been manufactured by AERO Laser. Briefly, it consists of a resonance lamp (discharge in a CO2 /Ar mixture), a fluorescence chamber, and an optical filter with two dielectric mirrors.
The spectral transmission of the optical filter is centered at the strongest emission band of the CO lamp (1-0, l=151nm). Because of the strong absorption that O2 has in the spectral region of 150nm, the optical filter is continuously flushed with a small flow of N2 (50 ml/min STP, purity 99.999%).
The fluorescence is detected with a PMT through two suprasil lenses. In order to eliminate an interference of H2O, the sample air is passed over a bed of Drierite (CaSO4 with humidity indicator). The pressure regulated inlet allows operation at ambient pressures from 200 up to 1000 mbar. Onboard gas supply (discharge lamp/ optical filter) is sufficient for several weeks operation.
Absolute calibrations are routinely made during flight using secondary standards containing about 400ppb CO, which are calibrated against a standard (Fa. Messer Griesheim). Also, a blank is determined using a filter containing hopcalite to remove the CO from ambient air. Calibration and blank are repeated every 30 minutes with a duration of 2 minutes.

The specifications of the instrument as used for EULINOX in 1998 are the following:

Time resolution: 1 sec
Detection limit (2 s) 3 ppb in 1 sec
Precision at 100 ppb 2 ppb in 1 sec
Accuracy 3% or 3 ppb
Linear response 0 to >12ppm


References

Gerbig, C., D. Kley, A. Volz-Thomas, J. Kent, K. Dewey, and D.S. McKenna, Fast-response resonance fluorescence CO
measurements aboard the C-130: Instrument characterisation and measurements made during NARE '93, Journal of
Geophysical Research, 101, 29229-29238, 1996.

Volz, A., and D. Kley, A Resonance Fluorescence Instrument for the In-Situ Measurement of Atmospheric Carbon Monoxide, J. Atmos. Chem., 2, 345-357, 1985.

J(NO2)-Radiometer (DLR-OP):

The J(NO2)-Radiometer determines the rate of the in-situ NO2-photolysis in the atmosphere via a continuous measurement of the actinic flux in the appropriate wavelength of the 4-Pi-sr-hemisphere. The basic design is adopted from the Junkerman, Platt and Volz (J. Atm. Chem., 1987). At photostationary state conditions in the atmosphere the following equation is valid:

J(NO2)=k [O3] [NO] / [NO2]
 
 

Radiometer

Dropsonde:

CN-Counter:

Measuring systems on board the DO 228

Personal involved:

Patrice Blanchet (ONERA-France)
Janine Baehr (DLR-OP)
Gerd Uhlemann (DLR-OP)

CO2 (ONERA-France):

The CO2 is measured with a differential , non-dispersive, infrared (NDIR) gas analyser (LI6252, LI-COR). The measurements are based on the difference in absorption of infrared radiation passing through two sampling gas cell. The reference cell is used for a gas of known CO2 concentration, and the sample cell is used for the sample gas. A 150 nm bandpass optical filter is used to tuned the CO2 detector to the 4.26  micron absorption band for CO2. To prevent measuring errors caused by pressure fluctuations, the reference and sample air pressure are kept constant by two absolute pressure controllers (100-1000 hPa 1%) before the chambers, and a differential pressure controller (± 1 hPa 1%) behind the chambers. The sample air is pumped by a membrane pump. The system allows in flight calibration, by directed hight and low CO2 concentration gas into the sampling cell.
The averaging time can be selected between 0.1 to 30 seconds. All these features provide a noise level that is 0.2 to 1 ppm with a 1 to 0.1 seconds signal averaging.
 

CO2 instrument (ONERA)

O3 (DLR-OP):

NO/NO2 (DLR-OP):


Interferometer for 3D lightning location

ONERA

Persons involved

Pierre Laroche (ONERA DMPH/EAG)
Patrice Blanchet (ONERA DMPH/EAG)
Claire Théry (ONERA DMPH/EAG)
Eric Defer (ONERA DMPH/EAG)
Guy Blanc (ONERA DMPH/EAG)

3D lightning locations are obtained with a VHF interferometer. The equipment consists in two remote stations which provide the angular locations of the VHF sources emitted by the different components of the lightning flashes. Each station is made of a 10 m high mast supporting circular vertical dipoles array. The « 2D » station at Oberschleissheim, is equipped with an azimuth sensor. This 8 dipoles array delivers the azimuth of the sources with a 0.25 degree resolution. The « 3D » station at Wielenbach is equipped with the same azimuth sensor and an elevation sensor - a 16 dipoles array - with a 0.5 degree resolution at 22.5 degrees elevation. The data are store at each station on hard disk. 3D data reduction are done off-line. The distance between the two stations is 49.2 km. Each station are synchronized with GPS signal. The time resolution is about 23µs and the system can acquire up to 4000 locations per second. The range of the 3D analyses is limited to about 50 km from the 3D station. The calculation is limited to areas such that the base line is view with an angle of 15 and 150 degrees. No location is available on the base line.

The system has a low resolution 2D real time capability. Low resolution, low rate data are transmitted by modem to a central station installed in the EULINOX’s operation room. Real time VHF lightning locations are available here and in the radar control room. Time resolution is 100 µs and the maximum acquisition rate is 100 locations per second.

References

P. Richard, A.Delannoy, G. Labaune and P.Laroche Results of spatial and temporal characterization of the VHF-UHF radiation of lightning J.G.R Vol. 91 n D1, 1986

P. Laroche, A. Bondiou, P. Blanchet, J. Pigere, M. Weber and R. Boldi 3D mapping of lightning discharge within storms 1994 Int. Conf. On lightning and Static Electricity, Mannheim Germany 1994. ONERA TP n 1994-186

2D antenna at Oberschleissheim 3D antenna at Wielenbach