Monday 20 August 2018

Looking back at the 2012 ice melt in context

What we are currently observing in the Arctic has reminded me of this article from Robertscribbler from the 2013 melt season.

The photo is still on my Facebook page.

North Pole Melting: Ice Camera 2 Swims as Camera 1 Gets its Feet Wet

Camera 2 in deep water at North Pole. Image sourc: APL

Robertscribbler,

25 July, 2015

This summer has seen a great number of extraordinary events resulting from human caused climate change. These include massive heat dome high pressure systems setting off record droughts, fires and heat waves, Arctic temperatures rocketing into the 80s and 90s, Europe and Canada suffering some of their worst flooding events in history and a crazy US weather system moving backwards against the prevailing weather pattern for more than 3,000 miles. Add to these record events a substantial melting of ice in the Arctic’s most central regions, and you end up with rather strong proofs that our greenhouse gas emissions have permanently altered the word’s weather.

From late May to early July, a persistent Arctic cylone (PAC 2013) first fractured ice near the North Pole, then consistently widened and melted the gap it created. Now a large triangle of very thin ice extends from the North Pole south and eastward toward the Laptev Sea. The section of meter or less thickness keeps widening even as gaps continue opening in the ice and melt ponds form over many of the remaining flows.

Further north and on toward the western side of the North Pole, two cameras supplied by the Applied Physics Lab and funded through a National Science Foundation grant are performing their own daily recording if this major melt event. The melting, which from the satellite, appears to have turned the sea ice near the North Pole into swiss cheese has had a marked effect on visible surface conditions as well.

Sea ice swiss chees as seen through the clouds near the North Pole. Image source: NASA/Lance Modis

Of the two ice cameras, #2 so far has seen the most action. On about July 13th, melt puddles began to form in the region of Camera #2. By earlier this week, the camera was deep in a growing pool of ice melt. By today, the water had deepened further covering all the markers surrounding both the camera and its related sensor buoy. Water now appears to be about 3 feet deep and the pond just keeps growing and growing (you can read more about the saga of Ice Camera #2 here).

But now, Ice Camera #1 appears to be about to suffer the same fate. Over the past couple of days, melt ponds have now also been forming in the vicinity of Camera #1. You can see this new set of melt puddles here:

Puddles form near North Pole Camera 1. Image source: APL

Note the melt puddle snaking its way behind the wind vane visible in the camera’s field of view and on toward Camera #1 itself. If conditions at this camera are similar to those near Camera #2, then we can expect Carema #1 to be swimming in about ten days time.

With temperatures remaining above freezing for much of the Central Arctic, melt conditions have tended to dominate. Now, most of the remaining ice is rather weak, with a thickness of about 2 meters or less. And with so much of this thin ice in areas near the North Pole, a possibility exists that much of this region will melt out over the next 6 weeks or so.

As for the Ice Cams? It appears that #1 may soon join #2 in the drink.

The following is from Wikipedia

Melt ponds are pools of open water that form on sea ice in the warmer months of spring and summer. The ponds are also found on glacial ice and ice shelves. Ponds of melted water can also develop under the ice.

Melt ponds are usually darker than the surrounding ice, and their distribution and size is highly variable. They absorb solar radiation rather than reflecting it as ice does and, thereby, have a significant influence on Earth's radiation balance. This differential, which had not been scientifically investigated until recently, has a large effect on the rate of ice melting and the extent of ice cover.[1]

Melt ponds can melt through to the ocean's surface.[2] Seawater entering the pond increases the melt rate because the salty water of the ocean is warmer than the fresh water of the pond. The increase in salinity also depresses the water's freezing point.

Water from melt ponds over land surface can run into crevasses or moulins – tubes leading under ice sheets or glaciers – turning into meltwater. The water may reach the underlying rock. The effect is an increase in the rate of ice flow to the oceans, as the fluid behaves like a lubricant in the basal sliding of glaciers.[3]

Effects of melt ponds[edit]

See also: Glacial motion

The effects of melt ponds are diverse (this subsection refers to melt ponds on ice sheets and ice shelves). Research by Ted Scambos, of the National Snow and Ice Data Center, has supported the melt water fracturing theory that suggests the melting process associated with melt ponds has a substantial effect on ice shelf disintegration. [4] Seasonal melt ponded and penetrating under glaciers shows seasonal acceleration and deceleration of ice flows affecting whole icesheets.[5] Accumulated changes by ponding on ice sheets appear in the earthquake record of Greenland and other glaciers:[6] "Quakes ranged from six to 15 per year from 1993 to 2002, then jumped to 20 in 2003, 23 in 2004, and 32 in the first 10 months of 2005."[7] Ponding in the extreme is lakes and lakes in association with glaciers are examined in the particular case of the Missoula Floods.