Fig. 2: Back-trajectory analysis and contribution from different surface types to the observed isoprene.
From: Atmospheric isoprene measurements reveal larger-than-expected Southern Ocean emissions
a Map of composite chlorophyll-a concentration (strip legend on the left) from MODIS-Aqua from 25 Jan to 17 Feb 2017, corresponding to the second leg of the Antarctic Circumnavigation Expedition (ACE). The ACE track is shown as a black solid line, with overlaid atmospheric isoprene mixing ratios (strip legend on the right). The back-trajectories, shown as thin coloured lines, are adjusted for the isoprene lifetime at each point along the cruise track, with a maximum allowed lifetime of 48 h. The colour of each back-trajectory is the same as the isoprene mixing ratio at the point along the cruise track from which it originates. Ice shelves are shown as dark grey areas. See also Fig. S4 for a version of this map showing Sea Ice Fraction. b Normalised distributions of isoprene mixing ratios influenced by different surface types.
