There has been a seeming pause in the melt, according to the extent graph that many take great stock in.
This is likely wind-driven, and due to ice that was compressed towards the center of the Pole and towards East Siberia spreading back out. Ice has moved south into waters that were ice-free north of the Canada-Alaska border, and back into the polynya to the northwest of Hudson Bay, and currently a surge of ice seems to be flowing from the Pole back toward the North Atlantic and Svalbard.
At times this spreading-out of ice can exceed the area actually melted, creating an uptick in the extent graph. To prevent panic and rash behavior among Alarmists, I should hasten to add that the “growth” is largely an illusion. In fact the total amount of ice has started it’s yearly decline, as there is little cold air remaining to form any new ice, much of the residual cold within the ice has faded away, and the water under the ice has started its yearly ablution from beneath.
Also the ice isn’t particularly elastic. When you crunch it together and then spread it apart, it doesn’t flex like an accordion, but rather creates a lot of piled-up pressure ridges when crunched, and a lot of leads of open water when it spreads. The leads (cracks) even show on the NRL concentration maps, which means they must be large, for the satellite is unable to see the thinner cracks.
It is at this point the Arctic Sea ceases to be a solid sheet of ice, and increasingly becomes many smaller chunks of ice jostling together. This is why is is more correct to refer to the ice as “sea-ice”, rather than an “ice-cap”. In essence it is a closely packed collection of flat bergs. The leads between the bergs can seem to “fill in”, in the above map, but it is seldom due to refreezing, until late August. Sometimes the winds blow the bergs together, and sometimes the pressure ridges on the bergs fall apart into many small chunks of ice that clog up the leads with what at times looks much like slush.
The thickness map below is a brave attempt to average out the differences in highly variable bergs of ice, and is a good guess at a mean thickness. It is interesting to compare the “cracks” in the concentration map with the thickness maps. Sometimes things don’t quite add up. Many cracks in twelve-foot-thick ice may make the ice suddenly look nine-feet-thick, when in fact it is still twelve-feet-thick, but with leads of open water between the floes.
As time passes you learn to sense stuff going on in these maps that is hard to quantify. Ice that looks very flimsy may endure even as ice that looks thick and tough vanishes in a matter of days. The two biggest factors seem, to me, to be a problem with measuring the pressure-ridges, which are extremely hard to see from the level of satellites but can increase the bulk of bergs in floes significantly, and, second, the fact much of the melt comes from beneath. Despite efforts to measure the temperature of the water under the ice the reality of the entire under-ice area remains largely a blank map. When people assert they are certain the water beneath the ice is warmer than last year, or colder than last year, or the same as last year, I humbly suggest they are guessing. I know I am.
As the melt proceeds we are heading to the days in late July and early August when melt-water pools will form and the floes of ice will look like this:
This picture is from 2005, as I recall (but I could be wrong, and will accept correction gladly). It is not from a recent summer, when I seemed to notice the melt-water pools often frozen over and dusted with snow. The picture shows a number of things.
First, it shows how difficult it is for Satellites, whether measuring dark areas or water-that-microwaves-can’t-penetrate, to tell melt-water atop a flat, solid berg from open water.
Second, it shows what is behind the ideas concerning “albedo”, for an ice-covered sea is by no means white during the height of the thaw.
Third, it shows some pressure-ridges on the ice, where pools don’t form.
What it fails to show is the melt from beneath, which continues to be where the study is focused.
This is being done by hard-working scientists behind the scenes who likely find politicians a bother, but must genuflect because work in the arctic is expensive. It pays to be polite, and not call the person holding the purse-strings a moron, even if they are one.
As was pointed out in a comment at this site, the summer storm of 2012 got everyone’s attention because 200,000 km2 of ice vanished in a matter of days.
The discussions about this storm involved whether the ice was melted by the storm, or would have melted anyway. (My own view is that the melt was sped up, and some ice that might have hung on in a calmer situation was melted when milder waters were churned up from below and mixed with the ice-protecting, thin, cold layer of slightly less saline water at the surface.)
The following summer ended with another storm, right when the ice was at its minimum and at its weakest.
This storm did not result in much ice melt at all, which of course makes one wonder. People smarter than I have studied the differences between the two summers.
It can be seen that temperatures were generally colder, but the disconcerting thing was that north of Bering Strait, where the ice-melt was most pronounced in 2012, there wasn’t that much of a difference in temperatures. It is also disconcerting that there was lower pressure over the Pole in 2013, because past history would have us expect less ice on such summers. In the end there was the sneaking suspicion that the greatest factor influencing the ice wasn’t up in the atmosphere, but was in the ocean beneath.
This in turn led to a lot of guess-work by people like me, including Alarmists, and, because it was guess-work, the conclusions varied wildly. What was needed was better buoys, and they did appear. They are marvelous designs, with sensors at various depths, but I have a sense they failed to sense what politicians wanted, for the data hasn’t been trumpeted in front page headlines, and in fact I can’t find much that is made readily available to laymen. So I am basically still guessing.
One thing politicians didn’t like was hearing that the atmosphere doesn’t have much effect on sea-ice. If you are waving your arms about the dangers of CO2 in the atmosphere what you want to hear is that the atmosphere has an enormous effect. The second-best thing would be that the atmosphere has an immediate and mighty effect on SST’s (Sea Surface Temperatures) but this too led to problems. For one thing, the data didn’t show SST rising in the desired manner, or at all. Secondly, scrutiny of the SST data showed some problems, especially concerning one of the Alarmists favorite maps.
This map, which always shows the sea-ice sitting amidst crimson, has some sort of a glitch in its make-up, as ice-water cannot get colder without becoming ice, yet it shows ice-clogged waters as being “above normal”. Impossible, but this did not keep Alarmists from constantly referring to it. And perhaps it was produced to keep politicians happy, but my conclusion is that it is red because it is embarrassed.
In any case, if you desire be surprised by ice that should melt failing to melt, use the above map.
What I use is observations of how much open water is exposed during the winter, and observations of the SST at the entrance regions of the Arctic Ocean, and to a lesser degree how much ice melts in the currents leading into the Arctic Ocean. Surely this not a very precise manner of measuring, and it would not at all surprise me if I turn out to be wrong. However my sense is that the melt-from-beneath will not be as vigorous this year as it was last year, when the “Warm Blob” invaded through Bering Strait.
In terms of above-ice temperatures, we continue to experience our warmest spring in years, which I imagine is the lagged effect of the El Nino, which is now gone.
I do not expect to see, in the above graph, any effect from the developing La Nina until late in the summer, but will be watching carefully to see if I notice any effects from the “Quiet Sun”. One effect would be increased cloudiness, but we have only one camera this year. O-buoy 14 has been dreary and gray, day after day. It’s a bit of a drag, as I originally started viewing the ice because the views were so gorgeous when it is sunny. But my wife puts up with me even though I’m dreary and gray, so I guess I’d best not complain.
A lot of the dreary weather is due to the low over the Pole gradually filling, as other lows roll east along the Siberian coast and then swing north to reinforce the general morass of low pressure over the Pole.
All these maps have midnight to the Bottom, but the next one has midnight at the top, in Bering Strait, so you can see it does get colder north of Alaska in the wee hours of the morning, even during June when the midnight sun is shining. The diurnal swing in temperatures roams around the Pole like the hands of a clock.
Originally high pressure was forecast to start building over Beaufort Sea today, perhaps bringing some sunshine to our camera, but now it looks like the low moving east off East Siberia is going to continue counterclockwise right around. As it approaches Beaufort Sea it may push sea-ice away from the coast again. Then it is forecast to swing up to the Pole. We’ll see about that.
POST SCRIPT: The low did swing up to the Pole, and was dubbed “Ralph” in the following post.