Fig. 4: Effect of IPO on the near-term projection of the PWC under the RCP8.5 scenario.
From: A very likely weakening of Pacific Walker Circulation in constrained near-future projections
a The 36-year running trends in PWC index [units: Pa (36 year) −1] and IPO index [units: K (36 year)−1] during 1980–2051 obtained from six large ensembles (LEs). Dashed Lines with squares in purple (orange) and blue (red) indicate the ensemble mean IPO (PWC) index trends by LEs and the best match members (BM members), with error bars representing the ensemble member spread. The horizontal axis marks the end year for the 36-year segment. b Histograms (bars) and fitted distribution (lines) of IPO index trends [units: K (36 year)−1] derived from the BM members. The blue (red) bars and fitted curve show the frequency of occurrence [units: %] of the IPO index trends for present (future) climate. Black line shows the observed IPO index trend derived from ERSST v4. The red and blue triangles denote the ensemble mean of the distribution with the corresponding colors. c The same as b but for PWC index trends [units: Pa (36 year)−1]. Black lines denote the observed PWC index trends derived from HadSLP2, ERAIM, and ERA5. Differences between the future and present distributions for IPO index trends and PWC index trends are significant at 99% confidence level.
