What’s up (down) with Arctic Sea-Ice: Extent, Thickness, Volume Dynamics and Thermodynamics // Sep 12, 2019
In September, 2012 Arctic sea ice extent (regions with at least 15% sea ice concentration) set a record low extent, far below any previous year and subsequent year, until now.
This year, up until about mid-August, sea ice extent closely tracked 2012, in fact was even lower than 2012 for long periods of time. Then, quite unexpectedly, 2019 melt significantly flattened out, stalling to be far behind 2012.
In this first of a series of videos, I discuss possible reasons for this stalling, in light of the fact that sea-ice volume continued to track closely to that in 2012, with no sign of stalling.
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New Ice Behavior Regime for Arctic Sea Ice Melt // Sep 132, 2019
I continue discussing details of Arctic sea ice melt, including the puzzling stalling of the extent drop in mid-August; yet continuation of volume loss to match 2012 (year that set records for both lowest volume and lowest extent).
Physical properties of the sea ice remaining are different since most of the stronger, purer (less salt content), thicker, older multi-year ice has melted out, or been exported and melted, leaving behind only weaker, saltier, thinner, younger first year and second year ice. We are in a new ice behavior regime, with different melt and freeze dynamics.
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Is Climate System Internal Variability Significantly Messing with Arctic Sea Ice Demise Predictions? // Sep 13, 2019
Continuing my Arctic sea ice loss videos, I discuss a paper on sea ice thickness variability arguing that internal variability of the climate system is very large, and thinner ice is even more sensitive to internal variability.
It suggests that we cannot predict complete loss of Arctic sea ice within a time window of less than 20 years; and that the difference in emissions pathways between RCP4.5 and RCP8.5 adds 5 more years to uncertainty. I am extremely skeptical of this result. To me, large variability means when a large negative swing occurs the sea ice will unexpectedly and rapidly vanish.
Ref: ‘How predictable is the first ice-free Arctic summer?’ 25 August 2016 17:44, Guest post by Dr. Alexandria Jahn.
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Variability of Arctic Sea Ice Thickness in Six Different Arctic Basins // Sep 14, 2019
Continuing my Arctic sea ice loss videos, I examine a paper on sea ice thickness variability that uses the PIOMAS model and a Community Earth System Model. Dividing the Arctic Ocean up into 6 different basins:
- Barents-Kara Seas,
- Laptev Sea,
- East Siberian Sea,
- Beaufort-Chukchi Seas,
- Greenland Sea, and the
- Central Arctic Basin (CAB).
It examines each basins sea ice thickness history and projections, and timing as to when basin thickness average falls below 0.5 meters. Greenland Sea lasts longest (cushioned by cold glacier meltwater); the CAB lasts next longest.
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