Fig. 1
Vertical profiles of CO2, CO, O3 and CH4 for each flight. Medians have been calculated for 1-km-height intervals (y-axis ticks mark the bottom of each layer). The horizontal error bars show the inter-quartile ranges over each altitude interval. In Flight 4, O3 profile, the 3rd quartile at 6–7 km is ~100 ppb.
Fig. 2
Species–species scatter plots. Data are coloured according to FLEXPART air mass origin, with calculated modal transport age indicated (in days, between parentheses in the legend, see Section 2.3 for details). Dashed red line represents background CO concentration and observations in hatched area are considered as non-polluted (see Section 3.1). (Left) CO–O3 scatter plot; (right) same for CO–CO2.
Fig. 3
Back trajectories for four specific plumes including pollution plumes related to biomass burnings and a marine plume, based on ECMWF wind fields. The lines show the mean back trajectory for each one of the four plumes. In addition, every 24 hours each particle cloud's position is divided into four clusters (see text for details), coloured according to their mean altitude. The numbers in each cluster's daily position symbol corresponds to the number of days prior to the particles’ release. The aircraft pathway is highlighted by grey solid line; superposed light blue lines figure plume M observations’ positions. Orange dots are positions of fires detected by the MODIS instrument from 11 to 20 April (from the Fire Information for Resource Management System, available online at http://earthdata.nasa.gov/data/near-real-time-data/firms).
. Campaign description
Table 2
Instrument characteristics
Table 3
Selected single plumes and specific events
−2.26A215 Apr. 05:2056.485.71100398.0±2.71920±1261±0.0181.2±6.80.97
6.10.68
0.33A315 Apr. 23:1562.6115.34500394.8±0.61838±1163.2±1.7171.0±13.70.94
27.5–A416 Apr. 05:1559.5112.56600397.4±1.31858±1960.7±0.6162.3±1.7––A518 Apr. 07:2556.4101.81000401.4±0.61862±1454.4±0.6165.9±4.40.74
12.2–A618 Apr. 04:3055.791.55200396.6±1.11860±2167.5±4.4174.6±17.50.81
12.30.56
0.45A718 Apr. 05:1555.388.23000398.4±0.51871±1759.6±1.7178.5±19.40.85
11.00.73
0.13A818 Apr. 05:3055.386.31600398.8±0.51854±1752.3±1.7166.6±2.9−0.60
0.81S18 Apr. 03:0055.998.56700388.7±0.91801±23177±35.390±170.57
4.4−0.92
−2.06M16 Apr. 01:0061.8121.76700394.1±1.61824±2249±2.2125±90.94
11.1−0.77
−3.00
[i] Identifiers begin with ‘A’ for anthropogenic (Section 3.2), ‘M’ for ‘marine’ plume (Section 3.4), ‘S’ for stratospheric intrusion (Section 3.3). Coordinates are the average position for the selected plumes. Correlations are indicated only if significant, i.e. p <0.01.
Fig. 4
Stratospheric intrusion. (a) Time series for all measured trace gases. CO2 and CO data are not continuous because of concurrent in-flight calibrations and instrument correction; (b) ECMWF potential vorticity map at 450 hPa (≈5700 m), 18 April 03:00; and (c) Potential vorticity section along aircraft trajectory (coloured regarding CO2 concentrations). Dashed contours for potential temperature in K and solid contour for PBL origin in % calculated by FLEXPART 1 d before the snapshot.
Fig. 5
Measured O3 and air fraction originating from the North Atlantic lower troposphere for Flight 2 (16 April 2010). (Left) O3 mixing ratios measured during Flight 2 (red and green symbols) are superimposed over the overall campaign data (gray symbols); the air mass originating from North Atlantic at high latitudes is indicated in red; (right) measured O3 mixing ratios along aircraft pathway over FLEXPART-calculated North Atlantic origin, expressed in % of the original released particle cloud. The North Atlantic area is defined as: 64–71°N, 3°W–10°E, 0–2000 m (see red box in Fig. 3).