Fig. 3: Adjustments of PWC trends during 1980–2015 according to the observational IPO phase transition.
From: A very likely weakening of Pacific Walker Circulation in constrained near-future projections
a From left to right: the average of observed PWC trend, total PWC trends after adjustment (Trend_Adj, purple bars), IPO-related PWC trends (Trend_IPO, gray bars), forced PWC trends (Trend_F, orange bars) [units: Pa (36 year)−1] obtained from MPI-GE, CanESM2, CESM1, GFDL-ESM2M, CSIRO, GFDL-CM3, separately. Numbers in parentheses indicate the ensemble size. Error bars in observation and different large ensembles represent the full observational spread and one standard deviation ensemble member spread, respectively. b–g Histograms (bars) and fitted distribution (lines) of PWC index trends [units: Pa (36 year)−1] derived from different large ensembles. The blue (red) bars and fitted curve show the frequency of occurrence [units: %] of the PWC index trends before (after) the adjustments. Black lines denote the observed PWC index trends derived from HadSLP2, ERAIM, and ERA5. The numbers in percentage indicate the percentage of members showing positive PWC trends with corresponding colors. Differences between the original and adjusted distributions for all the models are significant at 99% confidence level.
