The 2018 melting season has started

For a while it looked like the record for lowest maximum was going to be broken for the third year in a row, especially after an extreme warm event shook the Arctic. But this anomalous heat was followed by anomalous cold, which was just enough to nudge JAXA sea ice extent above last year's record low maximum. By 13 thousand km2, to be precise, which is around 0.1% of total sea ice this time of year.

I don't mind, as I correctly guessed both this maximum's date as well as the final number on Arctic Sea Ice Forum polls, probably for the first (and last) time in my life as an Arctic observer, as the maximum is incredibly difficult to pinpoint.

Here's the best visual representation of maximums throughout the years, produced by ASIF member Hautbois, as it shows when the maximum of a given year was reached, as well as how high it got:

Not a record low maximum, but the fourth maximum in a row that has ended up (well) below 14 million km2. That's for JAXA sea ice extent data (formerly known as IJIS, now provided by ADS-NIPR).  The NSIDC has just reported that for their SIE product this year's maximum was also second lowest on record.

Looking at how much sea ice extent was created since the last minimum (total freeze), this past winter ended up fourth lowest since 2006. Of course, back in the day, minimums were higher than they are now, which meant there was less 'room' for re-freezing:

Here's the spectacular drop from anomalously warm to anomalously cold on the DMI 80N temperature graph, which normally isn't all that representative for the Arctic as a whole, but in this case it is:

Now that's quite the roller coaster ride. Lots of extreme weather, not just in the Arctic, but all over the Northern Hemisphere, ever since that sudden stratospheric warming event caused the polar vortex to split and fall apart, back in February. It'll take a while longer for things to stabilize, if stable is the right word for an atmosphere that continues to warm due to an increase in greenhouse gas concentration.

As can be seen on Wipneus' collection of regional graphs, it was Baffin Bay that was the largest contributor to ending the freezing season, and with Okhotsk about to join the party, it's downhill from now on:

That doesn't mean that things will get spectacular right away, even though 2018 is currently second lowest on the JAXA SIE chart. In fact, the sea ice pack will continue to thicken a while longer in the middle of the Arctic Ocean, even though melting will start all around the periphery (which is why volume reaches its peak in April). Nevertheless, it will be interesting to see how things get positioned before melt ponds start to form in May. Things have been especially crazy on the Pacific side of the Arctic. More on that later.

Further reading on the Robertscribbler blog: Unusually Warm Early Arctic Spring Predicted Following Second Lowest Sea Ice Maximum on Record

Comments

[Rob Dekker]

Thanks Neven !
I for one am glad that the melting season started.
It will put the focus back to climate and science after a winter of arguing politics on the ASIK :o)

[Rob Dekker]

Sorry. That was ASIF.

[VaughnA]

While arguing politics is likely pointless, there is an excellent running record of scientific evidence presented on this blog and the ASIF which explains the condition of the Arctic in an understandable manner for most of us amateur scientists or as I may say "lay scientists." It is compilations such as these that eventually will help "sway the masses," at least IMHO.
Many thanks to Neven and everyone else who contributes to this blog and the ASIF.

[Neven]

Speaking of ASIF, I forgot to mention that the 2018 melting season thread has also opened there.

[Neven]

I've also added a bar graph to the blog post, showing total freeze for the 2006-2018 period.

[John Christensen]

Speaking of melting; Rob, what is the timing of your first prediction for Sept SIE?

[Rob Dekker]

John, my prediction method, using NH snow cover, sea ice extent, and sea ice area as predictors, is useful with data from the end of May, but statistically significant only with data from the end of June.

Sorry, I still have not found any variables that make a statistically sound prediction earlier than that.

[Jim Hunt]

Apart from extent it's useful to also take a look at Arctic sea ice thickness at this time of year:

http://GreatWhiteCon.info/2018/03/the-2018-maximum-arctic-sea-ice-extent/

[The thickness maps] reveal large areas of relatively thin sea ice in the Okhotsk and Barents Seas where the ice can now be expected to melt as quickly as it formed. There is also remarkably little sea ice in the Bering Sea for the time of year.

P.S. The 2018 NASA Operation IceBridge campaign has just started:

https://forum.arctic-sea-ice.net/index.php/topic,2282.0.html

[wayne]

Hi Jim

Upon further research a sun lower than 5 degrees affects thermistor readings if without winds, I am working on the exact sun elevation.... Hope you had a chance to measure top of snow temperatures when you had some.

I naturally notice when the Arctic becomes dryer, hence colder during winter of course, but not for the sub-Arctic where the higher sun will warm the surface much quicker. So this small maximum volume is sparred from much further disaster by the drying up of the Arctic atmosphere more than 3 months late:

http://eh2r.blogspot.ca/2018/03/drying-out-arctic-ocean-atmosphere.html

Despite the good small cooling news all data points towards a massive melt come September, if the late drying of atmosphere accretes more sea ice where the sun is low, it melts it where it is high, especially at the fringes of the Arctic . Dry Arctic air is a 0 sum gain at this time of the year. Now is a matter of weather, no wide spanning fog and clouds are a disaster come mid April onwards.

[Kevin McKinney]

Thanks for another valuable summary, Neven! I have an odd feeling about this season, but we shall see how it plays out. "Odd feelings" are quite often nothing more than that.

[John Christensen]

Hi Rob,

Thank you for the reply!

Noting your factors (NH snow cover, SIA and SIE), I wonder why sea ice volume wouldn't make the list of significant factors.

See 2012 vs 2013:

- Sea ice volume (SIV) equal at beginning of melting season
- April SIE higher in 2012 than 2013
- Sept. SIE much lower in 2012 than 2013

Sea ice volume or distribution of the volume might have been able to better explain the actual difference in melting.

For 2018 compared to 2016 and 2017:

- April SIE lower in 2018 than 2016 and 2017
- April SIV (PolarPortal) higher in 2018 than 2016 and 2017

The increased level of compactness/thickness of the sea ice in 2018 IMO should favor a lower level of melting and therefore also relatively higher Sept SIE, so let's see.

That said, NH snow cover will probably also be higher in 2018 compared to past couple of years, which then alternatively will explain a reduced melting..
In general, weather patterns that cause low pressures to form over the Arctic Ocean from mid-late May probably will also help retain NH snow cover, although numbers not always reflect that.