It’s not November until tomorrow, but Andy Lee Robinson has just published the 2021 edition of his long running “Arctic ice cube” video series, based on the PIOMAS volume data. Here it is for your edification:
You may also wish to keep tabs on our deep dive into CERES top of the atmosphere energy flux data. Here’s a sneak preview:
In stark contrast to other recent years, northern hemisphere snow cover is very low at the moment:
Continue reading Facts About the Arctic in November 2021We’ve been following the voyage of the Canadian icebreaker CCGS Amundsen as he circumnavigated Banks Island. Now Amundsen is about to set off on the final leg of his 2021 Arctic campaign to conduct the “DarkEdge” study in northern Baffin Bay. According to the Amundsen Science web site:
7 October to 3 November – Cambridge Bay to Quebec City
During the final Leg of the 2021 Expedition, an integrated study (DarkEdge) will take place at the ice edge to study the key processes taking place during the fall-winter transition in northern Baffin Bay. The Sentinel North program will deploy an Autonomous Underwater Vehicle (AUV) and contribute to the Dark Edge campaign. The CCGS Amundsen will sail to Quebec City for the end of the annual expedition on November 3rd.
and according to Christian Katlein from the Alfred Wegener Institute:
Christian is also going to be posting a video log during the voyage. Here is the first episode:
Here is a picture of a HUGIN AUV via Christian on the Amundsen:
and here are moving pictures of one in action:
The Canadian Ice Service daily charts don’t currently cover the north of Baffin Bay, so here’s the most recent weekly which provides some idea of what Amundsen will be facing over the next few weeks:
As Amundsen prepares to begin his voyage to the DarkEdge, here’s a watery sun setting over Cambridge Bay last night:
Here’s the eighth video in Christian’s Sea Ice Stories series and the first from Amundsen itself, whilst moored in Cambridge Bay:
Amundsen has finally located a smidgen of sea ice in Baffin Bay, at approximately 76.10 N, 77.10 W. Click to enlarge:
Amundsen has managed to find some more significant sea ice, this time located at around 76.30 N, 78.70 W:
Watch this space!
By way of a change we start this month’s look at all things Arctic with some sea ice statistical analysis. Anthony Watts’ Arctic porky pie production line has been speeding up recently, and I am not the only one who has noticed. As part of his takedown of the latest “skeptical” allegations against the United Kingdom Met Office Tamino has been looking at trends in Arctic sea ice extent over at his “Open Mind” blog:
First and foremost, the yearly minimum is only one day out of the year. We have sea ice extent data throughout the year, and what happens during the rest of the year counts. Instead of using the annual minimum, let’s use the annual average. To avoid losing the most recent data, I’ll compute the yearly average for October through the following September rather than the usual (but arbitrary) January through December. I’ll also omit October 1978 through September 1979 because that year is incomplete. I get this:
Continue reading Facts About the Arctic in October 2021The annual averages show much less fluctuation than the annual minima, so we can estimate things like rates of change with greater precision. I find that there is statistical evidence that the rate changed over time. One model of such changes uses three straight-line segments with their changes chosen to best-fit the data, like this:
The results of the ARCUS Sea Ice Prediction Network August call have been released, and here is the outlook for the 2021 minimum September mean Arctic sea ice extent:
The median prediction for the mean sea ice extent during the month of September 2021 is 4.39 million km2. According to ARCUS:
As of 22 August 2021, the Arctic sea-ice extent was 5.58 (compared with 25 August 2020 value of 4.43) million square kilometers. Arctic sea-ice extent in 2021 remains well below the climatological median and has closely followed the 2012 values for much of the summer but has diverged to higher sea-ice extent starting in early August. The forecasts continue to support September 2021 mean sea-ice extent being well above the September 2020 value. July sea-ice retreat has been greatest in the Eurasian seas, particularly in the East Siberian Sea, making the 2021 ice edge well north of the long-term median edge in Eurasia. Sea ice retreated since the end of July along the northern coast of Alaska, although the ice edge is near its climatological position, which makes the Beaufort and Chukchi sea ice extent the largest at this time of year since 2006. A tongue of sea ice that has been present all summer continues to extend close to land in the Kara Sea, making the northeast passage likely to remain blocked for the first time in several years. Half the models which provide spatial data to the SIO predict that the tongue is likely to survive.
Now let’s take a look at a range of assorted extent measurements. Here’s the NSIDC’s 5 day average extent:
Continue reading The 2021 Arctic Sea Ice Minimum ExtentThis month has begun with a couple of CryoSat-2 related papers. First we have one that I unexpectedly I found out about via Twitter:
Regular readers will recall that the thickness in mid April by the AWI’s CryoSat-2/SMOS metric seemed remarkably low, so I had to ask this question:
Whilst we wait on those SnowModel-LG results does the CPOM’s new analysis offer any cause for comfort concerning sea ice thickness in 2021? I’m afraid not. Here’s an extract from the conclusions:
We found that interannual variability in average sea ice thickness of the marginal seas was increased by more than 50 % by accounting for variability in the snow cover. On a seasonal timescale we find that variability in the snow cover makes an increasing contribution to the total variability of inferred sea ice thickness, increasing from around 20 % in October to more than 70 % in April.
We also observed that the trends in SnowModel-LG data propagated through to the sea ice thickness time series, amplifying the decline in regions where it was already significant and introducing significant decline where it did not previously exist. This occurred in spite of the compensating effect of enhanced interannual variability.
Next there is a preprint from Arttu Jutila et al. at the Alfred Wegener Institute. According to “Retrieval and parametrisation of sea-ice bulk density from airborne multi-sensor measurements“:
Knowledge of sea-ice thickness and volume depends on freeboard observations from satellite altimeters and in turn on information of snow mass and sea-ice density required for the freeboard-to-thickness conversion. These parameters, especially sea-ice density, are usually based on climatologies constructed from in situ observations made in the 1980s and before while contemporary and representative measurements are lacking. Our aim with this paper is to derive updated sea-ice bulk density estimates suitable for the present Arctic sea-ice cover and a range of ice types to reduce uncertainties in sea-ice thickness remote sensing. Our sea-ice density measurements are based on over 3000 km of high-resolution collocated airborne sea-ice and snow thickness and freeboard measurements in 2017 and 2019.
Some slightly strange English in there, but interesting nonetheless and an complement to Robbie Mallett’s paper above.
In addition to the paper itself Stefan Hendricks has posted an explanatory thread on Twitter:
From Stefan’s Twitter thread:
Main findings: The density values are higher than what we get with the climatology values, more so for multi-year sea ice than for first-year ice. Part of the explanation is that with the airborne data we also tried to get the bulk density of deformed ice that includes sea water.
We also found a robust relationship between ice freeboard and ice density. This will be useful for the freeboard to thickness conversion of satellite data.
If I’ve understood the 2 papers correctly Robbie’s change to estimated snow thickness implies less overall sea ice volume in CPOM’s future product, whereas Arttu’s change to estimated sea ice density implies increased sea ice volume in AWI’s version.
All in all I’m anticipating the summer 2021 high Arctic melting season with even greater trepidation than at the start of this month. Uncertainty is exceedingly unsettling!
[Edit – June 17th]
News arrives via an AWI press release, which also refers to the Ricker et al. paper we mentioned last month, of a new paper. The lead author of “Interannual variability in Transpolar Drift summer sea ice thickness and potential impact of Atlantification” is Jakob Belter. Some more famous names in the “et al.” section include Igor Polyakov, Robert Ricker and Stefan Hendricks.
According to the press release:
AWI sea-ice physicists report on the first indications that the rising ocean heat is also slowing ice formation in the Laptev Sea, which also includes measurements of the ice floe from the one-year MOSAiC expedition in late summer 2020. In it, the researchers analyse the long-term data from their sea-ice thickness measuring programme in the Arctic, ‘IceBird’, and trace the origins of the unusually thin sea ice that they observed from the research aeroplane in the northern Fram Strait in summer 2016. At that time, the ice was just 100 centimetres thick, making it 30 percent thinner than in the previous year – a difference that the researchers were initially unable to explain. “To solve the puzzle, we first retraced the ice’s drift route with the help of satellite images. It originated in the Laptev Sea,” explains AWI sea-ice physicist Dr Jakob Belter. The experts then examined the weather along the route. However, the atmospheric data for the period 2014 to 2016 didn’t show any abnormalities.
That meant the answer had to lie in the ocean – and indeed: from January to May 2015, experts from the University of Alaska Fairbanks recorded unusually high temperatures in the waters north of the Laptev Sea. We now know that the heat rose from the depths with Atlantic water masses, and slowed the winter ice growth. “Using the satellite data, we were able to show that the thin ice that we sampled in Fram Strait in July 2016 had previously passed through this unusually warm area off the Russian continental shelf,” says Belter. Furthermore, the ocean heat wave must have been so extreme that its effects on the growth in sea-ice thickness couldn’t be compensated for during its drift across the Arctic Ocean.
The conclusions from the paper itself include:
Further investigations and measurements are required to monitor the development of Atlantification in the eastern marginal ice zones. But in order to strengthen our conclusion that Atlantification is able to precondition sea ice and that this preconditioning persists far beyond the eastern Arctic, additional uninterrupted SIT time series are vital along the pathways and at the exit gates of Arctic sea ice. The presented summer SIT time series at the end of the Transpolar Drift is an important effort to establish long-term and large-scale measurements of SIT, especially during the melt season. Airborne EM measurements of SIT during IceBird campaigns provide the necessary accuracy and areal coverage that is unmatched by any other non-satellite SIT measurement approach. Russian shipborne SIT measurements show significant differences to EM-based measurements, but their regularity and spatial consistency enable the depiction of regime shifts in SIT that are hardly resolved by the presented EM SIT time series. Obtaining SIT distributions over large areas and developing and continuing long-term SIT time series will provide unique input data for modelling efforts and ultimately will improve predictions of Arctic sea ice and its thickness in the future.
Getting back to the conclusion of the press release:
The two new studies highlight the importance of long-term datasets for sea-ice research in the Arctic. “If we are to understand the changes in the Arctic sea ice, long-term observations of ice thickness using satellites and aircraft are vital. Combined with modelling data they provide an overall picture that is sufficiently detailed to allow us to identify the key processes in the changing Arctic,” explains Jakob Belter.
Inspired by my recent visits to Judith Curry’s blog this post will bring you links to the latest learned journal articles about Arctic sea ice. Together with occasional excursions into older and wider Arctic papers.
Judith’s “Week in Review” articles seem to last for a month, so this one will probably last for at least a year!
First up is an article apparently written by a regular reader of this humble web site! A University of Alaska article at phys.org begins:
In August 2016 a massive storm on par with a Category 2 hurricane churned in the Arctic Ocean. The cyclone led to the third-lowest sea ice extent ever recorded. But what made the Great Arctic Cyclone of 2016 particularly appealing to scientists was the proximity of the Korean icebreaker Araon.
For the first time ever, scientists were able to see exactly what happens to the ocean and sea ice when a cyclone hits. University of Alaska Fairbanks researchers and their international colleagues recently published a new study showing that sea ice declined 5.7 times faster than normal during the storm. They were also able to prove that the rapid decline was driven by cyclone-triggered processes within the ocean.
Note that it didn’t take us 5 years to write about the cyclone in question. Our article catchily entitled “The Great Arctic Cyclone of 2016” was published on August 13th 2016:
A storm is brewing in the Arctic. A big one! The crew of the yacht Northabout are currently sailing along the western shore of the Laptev Sea and reported earlier today that “The sea is calm. Tomorrow a gale 8. But this moment is perfect”.
That perfect moment will not last long.
I interviewed polar explorer David Hempleman-Adams about the succeeding moments once Northabout had returned to the UK. It seems riding out the cyclone was the most frightening experience he had ever had.
The University of Alaska article references the following peer reviewed paper:
“Role of Intense Arctic Storm in Accelerating Summer Sea Ice Melt: An In Situ Observational Study“
The next on my list of must read papers comes complete with a video:
Continue reading Month in Review – Arctic Science EditionLet’s start this somewhat belated article by looking at Arctic sea ice volume. The mid month PIOMAS gridded thickness numbers have been released to reveal these volume graphs:
Minimum volume for 2021 was 4.03 thousand km3 on September 17th, 2nd lowest in the PSC record.
Modelled volume is now in a “statistical tie” with 2012 for lowest on record for mid October. Here too is the PIOMAS thickness map:
Meanwhile for comparison purposes here is the first merged Cryosat-2/SMOS thickness map of the 2020/21 freezing season, hot off the presses at the Alfred Wegener Institute:
Continue reading Facts About the Arctic in October 2020I’ve been waiting for the results of the ARCUS SIPN August call, but despite the timetable specifying “26 August 2020 (Wednesday)” they’ve still not been published and I can wait no longer!
Hopefully the August “predictions” will be available soon, but for the moment let’s take a look at the July 2020 Sea Ice Outlook instead:
For the Arctic, the median July Outlook for September 2020 average sea-ice extent is 4.36 million square kilometers, essentially identical to the median prediction in the June report, with quartiles of 4.1 and 4.6 million square kilometers. For comparison, the historical record September low over the period of satellite observations was set in 2012 at 3.57 million square kilometers, and the second lowest record was 4.27 million square kilometers set in 2007. This year’s projection is close to the 2019 observed September sea-ice extent of 4.32 million square kilometers. As was also the case for the June report, only two of the outlooks project September sea-ice extent below the 2012 record. The consensus judgement against a new record low September sea-ice extent hence remains unchanged. Interestingly, as of this report, observed extent stands at a record low for this time of year.
Note that those numbers represent “September 2020 average sea-ice extent” and not the daily minimum. Let’s now take a look at the assorted different flavours of “Arctic sea ice extent” metric. Firstly here’s the NSIDC’s “Charctic” 5 day average extent:
Next here’s JAXA/ViSHOP extent, generally assumed to be a “2 day average”:
Next here’s the DMI version, which neglects to include 2012:
Continue reading The 2020 Arctic Sea Ice Minimum ExtentIn the absence of the usual mid month PIOMAS Arctic sea ice volume update I’m being moaned at by “angech” over on Judith Curry’s “Climate Etc.” blog:
Any ideas on why PIOMAS mid month update not out, other than not wanting to show a big recovery?
Unlike any of Judy’s denizens I checked out the comparatively new merged CryoSat-2 plus SMOS thickness maps from the Alfred Wegener Institute. “Measured” rather than “modelled” data must be a good thing surely?
Just in case there’s some significant difference between the “reanalysis” and “operational” versions of that product, here is the AWI’s most recent reanalysed Arctic sea ice thickness map, for the week ending January 11th:
together with the same date from the previous two years:
Make sure to take a close look at the white areas north of Greenland and the Canadian Arctic Archipelago showing sea ice over 4 metres thick.
Over the winter of 2018/19 ASCAT revealed that there was a relentless movement of multi-year ice towards both the North Atlantic and the Beaufort Sea.
Not unexpectedly that meant that ice in the northern Barents Sea was slow to melt out in the summer of 2019:
whilst after a fast start the melt in the Beaufort Sea also suffered a “brief hiatus” in June before ultimately melting out almost completely as well:
Perhaps a significant amount of the multi-year ice that survived the winter of 2018/19 has now simply melted away in warm water, to be replaced by much less robust first year ice in the area between the North Pole and the Siberian coast? It will be very interesting to see what the next PIOMAS update in early February reveals.
The next PIOMAS update referred to above has now arrived. Here’s the Polar Science Center’s graph:
Over on Climate Etc. angech is already exclaiming:
Strange it did go up a fair bit the old PIOMAS.
No publicity at the usual going down sites.
Actually it’s not at all strange, because thus far this winter the polar vortex has been remarkably well behaved. By and large cold air air has stayed in the Arctic. There hasn’t been much in the way of cold air intrusions into mid latitudes or warm air intrusions into the Arctic.
Hence it’s not at all surprising that the thickness of sea ice in the Arctic has been increasing slightly more quickly this winter than in other recent years. By way of some longer term context, here are the official Polar Science Center min/max trends:
Wipneus has just released the January PIOMAS gridded thickness map. Here it is:
As is all too frequently the case, AdR and other commenters below get very excited about trivial increases in sea ice extent without considering snow extent. One side effect of the lack of cold air outbreaks into mid latitudes so far this winter currently looks like this:
The AWI and PIOMAS sea ice thickness maps above look somewhat different at first glance. That being the case, I’ve written a program to crunch the AWI numbers. Here’s the result:
The source code plus raw and processed data can be accessed via the Arctic Sea Ice Forum:
“CryoSat-2/SMOS Arctic Sea Ice Volume”
Further support for my “polar vortex” theory, from Judah Cohen no less!
I think this plot best sums up the #winter for the Northern Hemisphere –#PolarVortex strength bouncing around from near (daily) record strong to normal all winter long. One more near record strong (PV) for latter half of February. Pretty much the nail in the coffin on this winter pic.twitter.com/OiSZw07VOF
— Judah Cohen (@judah47) February 10, 2020
Here’s the latest update of our novel NRT volume metric:
Please note that there is a known problem with the NRT data from January 31st onwards.
Here too are Wipneus’ latest high resolution AMSR2 area and extent graphs:
Wipneus has released his usual mid month PIOMAS update on the Arctic Sea Ice Forum:
I am forced to ponder once again why the CryoSat-2/SMOS thickness “measured” numbers just above seem to be more at variance with PIOMAS in 2020 than in previous years:
Here’s another weekly NRT volume update:
This time I’ve left off the NRT data from February 6th onwards, since the “issue” referred to above obviously hasn’t been solved yet. As an added bonus here’s a graph showing the trends (or lack thereof) on 3 dates during the October to April freezing season:
According to the MOSAiC Expedition’s web site:
In September 2019, the German research icebreaker Polarstern will set sail from Tromsø, Norway, to spend a year drifting through the Arctic Ocean – trapped in ice. The goal of the MOSAiC expedition is to take the closest look ever at the Arctic as the epicenter of global warming and to gain fundamental insights that are key to better understand global climate change.
In essence Polarstern will be following in the illustrious footsteps of Tara and Fridtjof Nansen‘s Fram before her, but with vastly more scientists in attendance than previous transpolar drift expeditions.
Hundreds of researchers from 19 countries take part in this exceptional endeavour. The MOSAiC expedition will bring a modern research icebreaker close to the north pole for a full year including for the first time in polar winter. The data gathered will be used by scientists around the globe to take climate research to a completely new level.
The expedition also bears a lot of resemblance to the more recent Norwegian Young Sea ICE Expedition, during which R/V Lance drifted embedded in winter sea ice, albeit nearer the North Atlantic.
The countdown to “the largest polar expedition in history” has begun:
Here’s an infographic to help explain what happens next:
The moment has arrived. The countdown is complete and the MOSAiC expedition begins today. According to the expedition web site:
After a decade of preparations, it’s finally time: this evening at 8:30 p.m. the German icebreaker Polarstern will depart from the Norwegian port of Tromsø. Escorted by the Russian icebreaker Akademik Fedorov, she will set sail for the Central Arctic. On board researchers will investigate a region that is virtually inaccessible in winter, and which is crucial for the global climate. They will gather urgently needed data on the interactions between the atmosphere, ocean and sea ice, as well as on the ecosystem. Thanks to the collaboration between international experts, the one-year-long ice drift past the North Pole will take climate research to a completely new level.
At the launch of MOSAiC Markus Rex, Head of the expedition from the Alfred Wegener Institute said that:
This mission is ground breaking. Never before has there been such a complex Arctic expedition. For the first time we will be able to measure the climate processes in the Central Arctic in winter. And so for the first time we will be able to understand this region and correctly represent it in climate models. The Arctic is the epicentre of global warming and has already undergone dramatic changes. And it is the weather kitchen for our weather in Europe. Extreme weather conditions like outbreaks of cold Arctic air here in winter, or heat waves in summer are linked to the changes in the Arctic. At the same time, the uncertainties in our climate models are nowhere bigger than in the Arctic. There aren’t any reliable prognoses of how the Arctic climate will develop further or what that will mean for our weather. Our mission is to change that.
Here’s the Alfred Wegener Institute’s 3 hour plus recording of the send off for Polarstern and Akademik Federov from Tromsø:
Here too are some alternative sources of information about the expedition:
BBC – https://www.bbc.co.uk/news/science-environment-49760460
New York Times – https://www.nytimes.com/2019/09/19/climate/mosaic-expedition-arctic.html
Polarstern is now within the initial target area, and is looking for a suitable ice floe to which she can attach herself:
Together with some other scientists, the head of MOSAiC, Markus Rex, flies over from #Polarstern to Akademik Fedorov, where they plan the next steps of searching for the right ice floe. #MOSAiCexpedition #Icedrift #Arctic
📸Esther Horvath pic.twitter.com/kGfg15CTF1
— MOSAiC Expedition (@MOSAiCArctic) September 28, 2019
Polarstern and Akademik Fedorov are still searching for a suitable sea ice floe:
The search for a suitable floe is still ongoing: Aboard Akademik #Fedorov survey flights take off whenever the often foggy #Arctic weather allows.#MOSAiCexpedition #Icedrift #Icefloe
Photo by: @AWI_de / Hans Honold pic.twitter.com/HmjaTsYNfP
— MOSAiC Expedition (@MOSAiCArctic) October 1, 2019
According to an article by Janek Uin from Brookhaven National Laboratory on the United States’ Department of Energy Atmospheric Radiation Measurement web site:
We finally found the piece of ice that will be the home for Polarstern for the next year. It’s a floe a few kilometers in diameter and with thickness ranging from half a meter to a few meters. Several ice floes were surveyed via helicopters from both icebreakers and by teams of scientists taking measurements on ice before a decision to pick this one was made. Now the two icebreakers are tied together as equipment, fuel, and people are transferred between the ships in preparation for deployment. While it’s exciting to see many new faces on Polarstern, we also had to say goodbye to some of the friends we had made on our way here.
There was also a lot of excitement today as two polar bears—a mom with her cub—wandered very close to Polarstern. Everybody who could rushed to the deck to try to capture photos of them in the diminishing daylight.
Via the MOSAiC Expedition Twitter feed:
On Friday evening at 9:30 p.m. boat time the team of #MOSAiCexpedition reached their destination: the floe which had been chosen some days before. #Icedrift #Arctic
📸Sebastian Grote pic.twitter.com/yChySCOqS0
— MOSAiC Expedition (@MOSAiCArctic) October 7, 2019
Watch this space!
