Spatial distribution of the rate of change of the potentially effective pre-season temperature (<i>T</i>_eff) from 1982 to 2008 (A).

<p>Spatial distribution of the rate of change of the SOS from 1982 to 2008 (B). Percentages of negative and positive SOS change rates in relation to the rate of change in <i>T</i>_eff. “Advance” means negative SOS change rates (the SOS tends to become earlier), and “Delay” means a positive SOS change rates (the SOS tends to become later) (C). Only pixels with a negative SOS–<i>T</i>_eff correlation that is significant at <i>P</i><0.10 level are included. Here <i>T</i>_eff is the mean temperature of the pre-season period that has most negative correlation coefficient (closest to −1) with SOS (see details in section 2.2).