Climatology of NO_y in the troposphere and UT/LS from measurements made in MOZAIC

Figures & data

Fig. 1 MOZAIC NO_y instrument installed in the avionic bay of the Airbus A340–300 D-AIGI operated by Lufthansa. The lower part shows the MOZAIC Inlet Plate with the different inlet probes, mounted at the fuselage of the aircraft. The fat arrow denotes the position of the inlet plate inside the aircraft.

Fig. 2 Time series of the number of NO_y measurements (1 min averages) obtained per month (red bars) and the number of concurrent NO_y and O₃ measurements (blue bars).

Table 1. Flight statistics for the MOZAIC NO_y instrument

	Flights MNR 4	Flights with NOy data		Flights with NOy and O3 data		Flights with NOy and CO data		Flights with NOy and O3, and CO data
Year	Flights	Flights	%	Flights	%	Flights	%	Flights	%
2001^a	455	114	24.18	110	100.00	0	0.00	0	0.00
2002	535	415	77.57	326	78.55	178	42.89	172	41.45
2003	690	514	74.49	507	98.64	503	97.86	503	97.86
2004	629	341	54.21	341	100.00	339	99.41	339	99.41
2005	350	149	42.57	149	100.00	111	74.50	111	74.50
Total	2659	1533	57.5	1433	93.7	1131	74.0	1125	73.6

^aSince May.

Fig. 3 Frequency distributions of the relevant contributions to the overall uncertainty calculated from all flights with valid NO_y data. Lower panel: uncertainties in calibration, i.e., sqrt((ΔS/S)²+(ΔE/E)²); upper panel: uncertainty of the artefact NO_y signal, ΔBG.

Fig. 4 Upper panel: geographical distribution of flights with NO_y measurements. Lower panel: airports with NO_y profiles and definition of regions used in the analysis. The colour bar denotes the number of profiles collected over the different airports.

Table 2. Availability of MOZAIC NO_y data and vertical profiles in the different geographical regions defined in Fig. 4

					NOy profiles
Region no.	Region	Region code	NOy observations (min)	No. of airports per region	No.	%
1	North America West	NAW	15 517	4	65	4.24
2	North America Middle	NAM	39266	7	197	12.85
3	North America East	NAE	69444	6	176	11.48
4	Central America	CAx	2776	2	23	1.50
5	South America	SAx	296	1	1	0.07
6	Greenland	GLx	22476	0	0	0.00
7	North Atlantic	NAt	136594	0	0	0.00
8	Tropical Atlantic	TAt	1316	0	0	0.00
9	South Atlantic	SAt	27	0	0	0.00
10	Europe	EUR	140728	6	708	46.18
11	Northwest Africa	NAf	5625	2	18	1.17
12	South Africa	SAf	0	0	0	0.00
13	Near East	NEx	43570	14	271	17.68
14	Mideast	MEx	3218	1	10	0.65
15	Southeast Asia	SAs	621	2	6	0.39
16	Far East	FEx	26186	7	57	3.72
17	Australia/New Zealand	AUS	0	0	0	0.00
18	Pacific	PAC	0	0	0	0.00
0	Missing destination			0	1	0.07
Total			507660	52	1533	100

Fig. 5 Vertical profiles of NO_y over Frankfurt. The lower boundary is determined by the pressure at which the instrument is switched into stand-by (initially at 800 hPa, changed to 900 hPa in April 2004). Colour bar: NO_y mixing ratio in ppb.

Fig. 6 Frequency distribution of NO_y and O₃ as a function of potential temperature (T _pot) for each season (spring: MAM; summer: JJA; fall: SON; winter: DJF).

Fig. 7 Frequency of measurements, mean mixing ratio and standard deviation of NO_y (left) and O₃ (right) as a function of potential vorticity (PV) for each season.

Fig. 8 Mean mixing ratios of NO_y for the four seasons (MAM, JJA, SON, DJF) in the vertical layers LS1 (upper panel) and UT (lower panel). Each data point represents a 1°×1° average. The colour code denotes the NO_y mixing ratio in ppb.

Fig. 9 Frequency distribution of the mean mixing ratio of NO_y for the layers UT, TP, and LS1 and for each season (all data without geographical selection). The parameters of the distributions are listed in Supplementary Table A3.

Fig. 10 Scatter plots of the NO_y mixing ratios against O₃ for the four seasons. The colour of the data points gives the concurrent potential temperature in K. The solid lines are linear fits to all data collected in the lower stratosphere (LS see definition above). The ellipses indicate individual data points with enhanced NO_y concentrations in the LS.