Figure 2
From: Impact on predictability of tropical and mid-latitude cyclones by extra Arctic observations
Karl, Ian, and Lionrock track forecasts. (a) Black line shows track of Karl from 0000 UTC 24 September through 1200 UTC 28 September in CTL1. Lines show ensemble mean TC tracks predicted by CTL1f (red line), OSEMf (blue line), OSECf (orange line), and OSEGf (green line). Squares show location of Karl in merging stage with extratropical cyclone at 0000 UTC 26 September (day 2.0 forecast). (b) As in (a), but Ian tracks from 0000 UTC 14 September through 1200 UTC 18 September by CTL1 (black line), CTL1f (red line), and OSEMf (blue line). Squares show location of Ian in merging stage with extratropical cyclone at 0000 UTC 16 September (day 2.0 forecast). (c) As in (a), but Lionrock tracks from 0000 UTC 25 August through 1200 UTC 29 August by CTL2 (black line), CTL2f (red line), and OSEBAPf (blue line). Circles indicate ensemble spread. The centres of circles show locations of ensemble mean. Circle radius indicates average difference in distance between locations of ensemble mean and of each member. Predicted upper-level geostrophic wind speed (300–500 hPa), Z300 (black contour), and PV on 330 K surface (green line) at 0000 UTC 26 September 2016 in CTL1f (d), OSEMf (g), at 0000 UTC 16 September 2016 in CTL1f (e), OSEMf (h) and at 1200 UTC 29 August 2016 in CTL2f (f), OSEBAPf (i). Black and red lines show tracks of Karl from 0000 UTC 24 September through 1200 UTC 28 September in CTL1f (d) and OSEMf (g), tracks of Ian from 0000 UTC 14 September through 1200 UTC 18 September in CTL1f (e) and OSEMf (h), and tracks of Lionrock from 0000 UTC 25 August through 1200 UTC 29 August in CTL2f (f) and OSEBAPf (i) for all ensemble member. Grid Analysis and Display System (GrADS) version 2.0.2 (http://cola.gmu.edu/grads/) was used to create the maps in this figure.
