In part 1 of this series I introduced readers to the Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH) data product and compared this with values obtained from the older Sea Ice Index (SII) data product. We noted the propensity for underestimation using passive microwave technology alone, this arising from difficulties in detecting the edge of sea ice, particularly when it’s not that thick. If we sit and cogitate on this we realise that the ‘tension’ between datasets primarily arises as a function of ice volume, with MASIE detecting rapid expansion of thinner ice and SII detecting when that expansion starts to gain decent volume. In turn these disparities might tell us something useful about ice-forming weather conditions. I’m loathe to say ‘climate’ because I’m one of those old-fashioned types who likes to use the 30-year WMO definition of climate.
Central vs. Non-Central Arctic
Before we go gadding about looking at melt patterns for the 16 different regions I’d like to draw our attention to a fundamental distinction between central and non-central Arctic ice dynamics. I shall start with an error bar plot of mean monthly ice extent for the period 2006 – 2022 by region: