Instrumentation on commercial aircraft for monitoring the atmospheric composition on a global scale: the IAGOS system, technical overview of ozone and carbon monoxide measurements

Figures & data

Fig. 1 Map showing the spatial coverage of 38494 MOZAIC flights between 1994 and 2014. Airline names are shown on the top right corner, and the MOZAIC system and Inlet are seen on the bottom left corner.

Table 1. Parameters provided by the A340/A330 aircraft system

Names	Units	Precision
Baro altitude^a	m	0.3
Radio altitude^b	m	0.1
gps altitude	m	0.1
Latitude/longitude	deg.	0.01
Air pressure	HPa	10
Total air temperature^c	°C	0.25
Static air temperature^d	°C	0.25
Aircraft ground speed	m s^−1	0.1
Aircraft air speed	m s^−1	0.01
Wind speed^e	m s^−1	0.01
Wind direction	(°)	0.01
Meridional wind speed	m s^−1	0.01
Zonal wind speed	m s^−1	0.01

^aThe baro altitude is the geopotential height computed from the aircraft static pressure measurements using the International Civil Aviation Organization (ICAO, www.icao.int) standard atmospheric profile.

^bRadio altitude is the altitude above surface, valid only below 2500 m.

^cTotal air temperature (also named stagnation temperature) is measured by a temperature probe mounted in Rosemount housing on the surface of the aircraft.

^dThe Static air temperature is calculated by aircraft computer, using the Mach number and the total air temperature.

^eWind speed and direction are calculated by the aircraft Air Data Computer.

Fig. 2 Scheme of the IAGOS system mounted on an Airbus aircraft (Package1+Optional Package2).

Fig. 3 Scheme of the IAGOS inlet plate fixed to aircraft fuselage.

Table 2. Aircraft currently equipped with the IAGOS instruments

Airline	Type	Tail sign	Installed in:	Date
Lufthansa	A340	D-AIGT	Hamburg/Frankfurt	July 2011
China Airlines	A340	B-18806	Taipei	June 2012
Air France	A340	F-GLZU	Paris	June 2013
Cathay Pacific	A330	B-HLR	Xiamen	July 2013
Iberia	A340	EC-GUQ	Tel-Aviv/Madrid	February 2014
Lufthansa	A330	D-AIKO	Malta	March 2015

Fig. 4 Package1 picture and schemes. Without H₂O and BCP boxes, Package1 weighs 35 kg and the dimensions are 630×450×314 mm. The main elements are listed and described in Table 3. (a) Photo of Package1. BCP box and H₂O box are fixed on top. The GSM antenna for data transmissions is seen on the connectors face bottom left side. (b) Scheme of Package1 inside. (c) Scheme of the upper shelf viewed from the top. (d) Scheme of the lower shelf viewed from the top.

Table 3. List and description of Package1 subassemblies

Main element	Function and description
Upper shelf
O3 device	O3 absorption cells, UV source, UV detectors (Thermo Scientific for Model 49)
O3 filter	O3 filter (MnO2) for O3 zeroing (Thermo Scientific, PN 14697)
Power supply board	Several protected voltages to the different elements (LGM Ingénierie)
Data acquisition system PC104	4 PC104 cards; Diamond Systems: Athena CPU, Serial ports(Relays Ballard Technology: PM429 for Arinc-429)
Flowmeters	CDK FSM series
Manifold	Teflon bottle connected with Teflon tubing (Bioblock 15032)
Pressure sensor	Pressure monitoring of the O3 cells (Thermo Scientific PN 9877)
Flow controls	Teflon 1/8 inch tubes with length adjusted to provide 2 L min^−1 for O3 path and 4 L min^−1 for CO path (see blue and pink spiral tubing in Fig. 4b)
Lower shelf
CO device	CO absorption cell, IR source, IR detector with its thermal regulation card, CO cell motor (Thermo Scientific for Model 48 Trace Level)
Internal pump	KNF and NPK09
O3 processing board	Control and signal acquisition/processing for O3 device (LGM Ingénierie)
CO processing board	Control and signal acquisition/processing for CO device (LGM Ingénierie)
O3 generator	Used for internal O3 calibration check (Thermo Scientific, FC001)
Air drier	Nafion multitube for drying the air prior to the CO cell (Permapure PD100T-12)
Gas pressure regulator	Pressure regulation (2 bar) in the CO cell (Bronkhorst P702C-GAC-22-V-005A)
O3 filter	To remove atmospheric O3 before CO measurements (Thermo Scientific, PN 14697)
CO filter	Sofnocat catalyst from Molecular Products Ltd. filled in Swagelock 304L-HDF4-75-PD (75 cm^3)
Electrovalves	Three Teflon valves for O3 (Teqcom), one stainless steel valve for CO (Thermo Scientific, 738)
GSM modem	Worldwide data transmission, four bands Wavecom, Package1 GSM Modem FastRack (evolution planned for 2015 with 3G Modem)

Fig. 5 Package1 air flow diagram within the upper and lower plates.

Fig. 6 IAGOS pump box – the box contains two pumps in parallel (see text), the electronic control cards and a Teflon solenoid valve. All tubing are Teflon-coated with a 1/4 inch diameter.

Table 4. Measured parameters stored during flights by the Package1

File Name ‘Refvol’ is P1 SN	Content	Number of parameter	Frequency
AYYYYMMDDHHMNSSIN.txt	CO zeroing parameters	8	10–20 min
CYYYYMMDDHHMNSSIN.txt	BCP data	17	4 s
DYYYYMMDDHHMNSSIN.txt	CO module functional parameters	11	1 min
EYYYYMMDDHHMNSSIN.txt	Flight chronological events	2	n/a
HYYYYMMDDHHMNSSIN.txt	H2O and T voltages	3	4 s
MYYYYMMDDHHMNSSIN.txt	Aircraft parameters	14	4 s
SYYYYMMDDHHMNSSIN.txt	Pump Box flow	3	1 min
VYYYYMMDDHHMNSSIN.txt	CO measurements	3	1 s
XYYYYMMDDHHMNSSIN.txt	O3 and pressure measurements	3	4 s
YYYYYMMDDHHMNSSIN.txt	O3 module functional parameters	11	1 min
ZYYYYMMDDHHMNSSIN.txt	O3 in-flight calibration levels	9	2 h

YYYY, year; MM, month; DD, day; HHMMSS, hour, minutes, seconds in UTC (take-off time); IN, instrument number (Package1).

Table 5. Summary of the IAGOS O₃ and CO instrument characteristics

	O3	CO
Technique	UV absorption	IR correlation
Noise and integration time	±2 ppbv; 4 s	±5 ppbv; 30 s
Precision	±2%	±5%
Horizontal resolution (cruise speed 250 m s^−1)	1 km	7.5 km
Vertical resolution (max vertical speed 15 m s^−1)	max 50 m	max 450 m

Fig. 7 Quick-look example. On top, flight information and external pump flow check (here displayed in Volts). Graphs of the flight route, flight altitudes, O₃ and CO vertical profiles and time series with clouds detected by the BCP shaded in grey. On the profiles, the thin dash lines represent the profile of the previous flight. On bottom, time series of H₂O sensor voltage, and the total and static temperatures measured by the aircraft and by H₂O sensor in its Rosemount housing (raw data not calibrated).

Fig. 8 The combined MOZAIC and IAGOS fleet have landed in more than 147 different airports around the world since July 2011. Symbol sizes are proportional to the total number of landings and takeoffs for a location. Monthly map of flights are available on the IAGOS website (www.iagos.fr/web).

Fig. 9 Examples of flight profile intercomparison automatically made available within the IAGOS database as soon as at least two flights land or take-off within a 3-h time window at the same airport. 53, 35 and 51 are the MOZAIC instruments, and 03 and 04 are the IAGOS instruments. Colours found in the profile plots correspond to the flight in the table on top. (a) Flight landing times at Frankfurt, (b) quick information, (c) routes around Frankfurt, (d) O₃ profile and (e) CO profile.

Fig. 10 Flight intercomparison scatterplots between the MOZAIC and the IAGOS instruments for O₃ and CO concentrations measured during ascent and descent profiles. Scatterplots compile 32 and 55 validated (L1) intercomparison profiles, respectively, for (a) O₃ and (b) CO recorded between July 2011 and December 2012. Dashed line is the 1:1 line and the grey shading represents the total instrument uncertainties. Red crosses and blue dots are the data measured below and above 1000 m, respectively.

Fig. 11 Example of flight intercomparison at cruising altitudes (>9 km). Plots are automatically made available within the IAGOS database as soon as at least two flights shared the same route distant by <0.5° of latitude/longitude and within in a 5-h time window. (a) Flight routes, (b) flight intercomparison summary table, (c) O₃ and cruising altitude and (d) CO and cruising altitude.