Fig. 6: WPEP estimation.
From: A fresh perspective on ENSO nonlinearity: the ENSO pattern continuum metric
a Hovmoller of total SST with seasonal variations (TO), averaged 5° N–5° S, as a function of time t (years) and longitude x (deg E), with directly estimated WPEP (white line) and 28.5 °C isotherm (green line). b Total SST T(x, t) (without seasonal variations) and its estimated WPEP (black line). WPEP from (a) is repeated (white line). c Total T(x, t) as in (b) with WPEP from (b) repeated (black line), also showing an optimized WPEP χg(t) (blue line, see text). χ(t) is estimated in the present paper as the black line in (b, c).
