Breakup date as a function of freeze-up date for the previous year for 1981–2014. Linear regression results for breakup date (Y) as a function of freeze-up date for the previous year (X) in the offshore data for 1981–2014. From top to bottom: values for slope, the Pearson correlation coefficient (R), and the coefficient of determination (R²). Values are only shown in colour for pixels exhibiting a significant relationship (p < 0.05); all other pixels are shown in gray. DOI: https://doi.org/10.1525/elementa.281.f7