Fig. 6: Comparison of seasonal trend errors for 200 hPa zonal wind and MSLP indices for re-forecasts and historical simulations.
From: Climate model trend errors are evident in seasonal forecasts at short leads
a Seasonal trend error for 200 hPa zonal jet indices for the North Pacific jet (DJF), South Pacific jet (JJA), North Atlantic jet (JJA), and Equatorial Africa easterly jet (SON) (regions shown on Fig. 5). b and c show trend errors for two MSLP-based indices: b the Arctic Oscillation and c North Pacific Index (see Methods). For each verification season, the first column shows the seasonal re-forecast trend error for each individual model and the re-forecast trend error for the multi-model mean, the second column shows the CMIP6 model trend error distribution and the third column shows two other observations-based datasets, relative to ERA5. These are averaged for two-season leads for the re-forecasts. Units are trend error per year as a percentage of the ERA5 index standard deviation. Statistical significance is indicated by darker symbols with a black outline.
