Because observed regime trends substantially exceed the forced LENS2 range for key regimes despite matching ensemble-mean signs, internal va
Because observed regime trends substantially exceed the forced LENS2 range for key regimes despite matching ensemble-mean signs, internal variability likely dominates the observed regime changes while a weak forced dynamical signal may be emerging.
Paper reconstruction — Dunkl, Bastos & Sippel (2026), European summer drying
The forced LENS2 ensemble mean has the same sign as all observed weather-regime trends, but the observed WR2 and WR3 trends lie entirely outside the ensemble range, and only 7 of 100 members have a more negative WR1 trend than observed.
CESM2 forced circulation trends are much weaker than the observed trends in every identified weather regime, implying that internal variability likely dominates.
Although the LENS2 ensemble-mean weather-regime trend has the same sign as every observed trend, only 7 of 100 members have a more negative WR1 trend than observed, and observed WR2 and WR3 trends lie wholly outside the LENS2 range.