Figure 5: Analysis of the relation between instantaneous properties and NOAA GER reforecast.
From: Dynamical proxies of North Atlantic predictability and extremes
(a,b) bivariate histograms of the ensemble spread 〈σSLP〉 at a lead time of +384 h as a function of the stability θ (a) and the instantaneous dimension d (b) of the initialisation field, for the period 2000–2015. The colourscale indicates the number of days with the same pair of parameters. (c,d) Case studies of how the reforecast trajectories diverge from the control run 〈SLPc〉 and their relation with ensemble spread, d and θ. (c) Reforecast for the 21/01/2000 corresponding to high d ≃ 18 with a moderate value of θ = 0.56. (d) Reforecast for the 12/01/2000 corresponding to high θ = 0.73 and moderate value of d = 14. The thick black lines show ensemble spread, while the thin coloured lines show the deviation of individual ensemble members from the control member (blue).
