2018 Sea Ice Thread

[aleCcowaN]

By the end of July the Arctic sea ice volume was 870 cubic kilometres above last year's (2017 was the lowest on record). The Arctic sea ice area is trending to reach a yearly minimum between 3.8 and 4.5 million square kilometres (second to sixth record low). Tomorrow it's going to drop below the 6 million square kilometres mark while losing half a million per week. Stay tuned.

 

[aleCcowaN]

This year's Arctic sea ice minimum was the sixth lowest in 40 years of satellite record.

Meanwhile, this year's Antarctic sea ice maximum was the fourth lowest in the same period (only 1986's was clearly lower). The myth about Antarctic sea ice growing is over.

By September 25th the global sea ice anomaly was -2,501,000 km2 and on October 13th, -3,189,000 km2, figures that are becoming increasingly usual in the few months around September Equinox.

Now, it started the sea ice event of the year: the Antarctic sea ice melting period, with its much more significant effect on the Earth's energy budget (as that ice is located in much lower latitudes during summer than it's northern counterpart).

 

[Trebuchet]

Any measurements of Antarctic land ice? Much more difficult, presumably, since you can't just see it with a satellite, but that's what's going to cause sea level rise.

 

[aleCcowaN]

Any measurements of Antarctic land ice? Much more difficult, presumably, since you can't just see it with a satellite, but that's what's going to cause sea level rise.

There are lots of sources for measurement, from gravimetric satellites to land ice "buoys". But the whole subject, interesting and worrying as it is, is outside the scope of this thread.

 

[lomiller]

Any measurements of Antarctic land ice? Much more difficult, presumably, since you can't just see it with a satellite, but that's what's going to cause sea level rise.

There are 2 different types of satellite measurements of Antarctic land ice, altitude and gravity. Both indicate West Antarctica is loosing ice rapidly but East Antarctica isn’t quite as clear. At least on study based on the altitude data claims a slight increase. Other studies based on altitude data suggest a slight declaim. Gravity measurements from GRACE suggest a slight decline.

The complication with altitude measurements seems to come from uncertainty in how much of what is being observed is less dense snow and how much is more dense ice.

Realclimate covers to issue here:
http://www.realclimate.org/index.php/archives/2015/11/so-what-is-really-happening-in-antarctica/