Day 1 of my voyage to the #Antarctic Peninsula on the #tallship #BarkEuropa: departing from #Ushuaia and sailing east along the Beagle Channel.
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Day 10 of my voyage to the #Antarctic Peninsula on the #tallship #BarkEuropa: landing on Jougla Point, a location formerly used by Whalers and literally a stone's throw away from the island where the former British base of Port Lockroy is located.
#BusmansHoliday@PoLaRobs third shot especially poignant
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@PoLaRobs I wonder how you feel about the theory of my former colleague Gene Domack (perhaps not his theory, but he was the first to share it with me) that increased meal from Antarctica will increase sea ice cover by freshening the surface waters around the peninsula and effectively raising ice's melting point.
@Brad_Rosenheim I think that theory has been the basis of several high profile papers. If there was any truth in it then sea ice extent west of the Peninsula and in the southern Bellingshausen Sea should have been increasing over the past few decades. In reality there has been a steady decline in sea-ice extent in these areas through the period of the satellite record, even while extent was steady or slightly increasing in other sectors up to 10 years ago.
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@Brad_Rosenheim I think that theory has been the basis of several high profile papers. If there was any truth in it then sea ice extent west of the Peninsula and in the southern Bellingshausen Sea should have been increasing over the past few decades. In reality there has been a steady decline in sea-ice extent in these areas through the period of the satellite record, even while extent was steady or slightly increasing in other sectors up to 10 years ago.
@PoLaRobs I think I've chatted with @carlosmoffat about it before, and he does the kind of modeling that would be important in assessing if this was happening.
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@Brad_Rosenheim I think that theory has been the basis of several high profile papers. If there was any truth in it then sea ice extent west of the Peninsula and in the southern Bellingshausen Sea should have been increasing over the past few decades. In reality there has been a steady decline in sea-ice extent in these areas through the period of the satellite record, even while extent was steady or slightly increasing in other sectors up to 10 years ago.
@Brad_Rosenheim
A further thought on this. The average surface water salinity in the Southern Ocean is about 34.5 ppt, which depresses the freezing point by nearly 2°C. If a large flux of melt decreases the salinity by 1 or 2 ppt, as happens around the sea ice edge when it is retreating in Spring, this raises the freezing point by around 0.1°C. I think other factors, including atmospheric and ocean temperatures and winds, are likely to be much more important in controlling sea ice extent. Furthermore, any melt added to the surface water in summer will be mixed into the upper ~200 m of the ocean by autumn storms before it can have much effect on new sea ice growth. -
@Brad_Rosenheim
A further thought on this. The average surface water salinity in the Southern Ocean is about 34.5 ppt, which depresses the freezing point by nearly 2°C. If a large flux of melt decreases the salinity by 1 or 2 ppt, as happens around the sea ice edge when it is retreating in Spring, this raises the freezing point by around 0.1°C. I think other factors, including atmospheric and ocean temperatures and winds, are likely to be much more important in controlling sea ice extent. Furthermore, any melt added to the surface water in summer will be mixed into the upper ~200 m of the ocean by autumn storms before it can have much effect on new sea ice growth.@PoLaRobs Yes, it would have to be a shirt term and localized effect at best, but the formation of ice, of course, would then limit vertical wind-driven mixing, making potentially more interesting.
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@PoLaRobs I think I've chatted with @carlosmoffat about it before, and he does the kind of modeling that would be important in assessing if this was happening.
@Brad_Rosenheim @carlosmoffat
I chatted with Carlos about this and other matters when he was visiting BAS a couple of years ago. If I remember correctly his view was that upwelling and mixing of CDW into surface waters was an important factor. -
J jwcph@helvede.net shared this topic
