Tag Archives: SIPN

The Sea Ice Prediction Network

The 2024 Arctic Sea Ice Minimum Extent

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The 2024 Arctic sea ice minimum extent will almost certainly occur at some point over the next month. The exact date and level will vary from one extent metric to the next. Here’s a comparison of the current JAXA extent with previous minima, courtesy of Zack Labe:

Here too is a more detailed look at 2024 extent compared with the 5 lowest annual minima in the JAXA record:

By way of comparison, here is the equivalent graph for the OSI SAF extent metric, which experienced an up tick yesterday but has now reached a new low for the year:

The Alfred Wegener Institute’s extent metric has flatlined over the last two days:

However AWI Arctic sea ice area is currently falling, which may well presage further significant falls in extent:

The NSIDC web site is currently “experiencing technical difficulties”, but hopefully we’ll be able to take a look at their extent graph in the very near future.

[Update – September 4th]

The NSIDC web site is back in action, and their 5 day averaged extent metric is currently still falling quickly:

The ARCUS Sea Ice Prediction Network August report has been published. Note that the predicted numbers are for the September monthly average extent rather than the daily minimum:

For the August Outlook, we received 24 contributions of September pan-Arctic sea-ice extent forecasts…

The August 2024 median forecasted value for pan-Arctic September sea-ice extent is 4.27 million square kilometers with an interquartile range of 4.11 to 4.54 million square kilometers. This is about 200,000 square kilometers lower than the June median and about 250,000 square kilometers lower than the July median, which reflects the faster than average ice loss during July.

The lowest sea-ice extent forecast is 3.71 million square kilometers and the highest sea-ice extent forecast is 5.23 million square kilometers. These extremes are actually higher, particularly on the low end, than the estimates from July.

[Update – September 9th]

There’s been the tiniest of upticks in the NSIDC 5 day extent metric. 1 thousand km² to be precise. However, the others are still slowly declining:

[Update – September 10th]

NSIDC extent has posted a new low for the year, and JAXA extent is still declining. However there has been a slightly more substantial uptick in the OSI SAF metric:

The current minimum is 4.64 million km² on September 8th.

AWI sea ice area has posted a convincing looking minimum on September 4th, which suggests that the central refreeze is already well under way:

[Update – September 17th]

JAXA/ViSHOP/ADS extent has risen significantly over the last two days:

It now looks highly likely that the 2024 minimum will prove to be 4.07 million km² on September 13th. That is 4th lowest for the date, but equal 5th lowest minimum in the JAXA record.

A closer look at some of the other extent metrics will have to wait until this problem is solved:

Not good timing for a data outage!

[Update – September 22nd]

SSMIS data has been flowing again for a couple of days:

This graph may be subject to revision if and when the missing data is recovered, but currently it looks as though the 2024 minimum of the NSIDC 5 day averaged extent metric is 4.28 million km² on September 11th.

[Update – September 24th]

The National Snow and Ice Data Center formally announced today that:

On September 11, Arctic sea ice likely reached its annual minimum extent of 4.28 million square kilometers. The 2024 minimum is the seventh lowest in the nearly 46-year satellite record. The last 18 years, from 2007 to 2024, are the lowest 18 sea ice extents in the satellite record…

Note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Arctic ice extent, as happened in 2005 and 2010. NSIDC scientists will release a full analysis of the Arctic melt season, and discuss the Antarctic winter sea ice growth, in early October.

The NSIDC also addressed the recent missing SSMIS data issue mentioned above as follows:

Note that a gap exists in the input source data between September 12 and September 18. This gap somewhat lowers our confidence in the minimum extent estimate. However, it appears that September 11 is the mostly likely date of the minimum based on data trends in daily extent values leading up to the 5-day average on September 11 and the extent values after data restarted on September 18. If extent did drop further between September 11 and September 18, it would have been marginal. If the input source data becomes available to fill that gap, our team will update the minimum estimate if necessary.

Watch this space!

Facts About the Arctic in July 2024

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The first sea ice outlook report for 2024 has been published by the Sea Ice Prediction Network:

This year’s median forecasted value for pan-Arctic September sea-ice extent is 4.48 million square kilometers with an interquartile range of 4.21 to 4.74 million square kilometers. This is slightly lower than the 2022 (4.57 million square kilometers) and 2023 (4.54 million square kilometers) June median forecasts for September.

The lowest sea-ice extent forecast is 3.1 million square kilometers, from the UK Met Office, which would be a new record low for the satellite period (1979-present); the highest sea-ice extent forecast is 5.21 million square kilometers, submitted by both the HEU Group and SYSU/SML-MLM, which would be the highest September extent since 2015:

There are three heuristic Outlooks, with a median of 4.32 million square kilometers and an interquartile range of 4.26 to 4.4 million square kilometers. Statistical submissions total fifteen Outlooks with a median of 4.68 million square kilometers and an interquartile range of 4.47 to 4.9 million square kilometers. There are nine dynamical model contributions. The dynamical models have a median forecast of 3.97 million square kilometers with an interquartile range of 3.68 to 4.35 million square kilometers.

Continue reading Facts About the Arctic in July 2024 →

Facts About the Arctic in September 2023

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There’s lots of coverage specifically about assorted Arctic sea ice extent metrics over on the “2023 Minimum Extent” thread. However we’ll start the September open thread ball rolling with a couple of cross posted images.

At the end of August JAXA daily extent was 7th lowest for the date, at 4.49 million km² :

The median prediction of the contributors to the August call by the Sea Ice Prediction Network for the September monthly average extent is 4.6 million km² :

Continue reading Facts About the Arctic in September 2023 →

The 2023 Arctic Sea Ice Minimum Extent

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It’s that time of year again! Tony Heller has been asserting that “summer is over at the North Pole” for several weeks now, and the 2023 Arctic sea ice minimum extent will occur at some point over the next four or five weeks. The exact date and level will almost certainly vary from one extent metric to the next.

To get the minimum extent ball rolling, here’s Signe Aaboe’s graph of previous summer minima based on OSI SAF data:

Here too is Zack Labe’s equivalent, based on JAXA data:

Continue reading The 2023 Arctic Sea Ice Minimum Extent →

Facts About the Arctic in August 2023

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We have grandchildren visiting this week, so it seems prudent to get the new open thread started a day early, and before they wake up!

The ARCUS Sea Ice Prediction Network July report has recently been published. Here’s the graphic overview of the 30 predictions for September sea ice monthly average extent:

The July median forecasted value for pan-Arctic September sea-ice extent is 4.66 million square kilometers with interquartile values of 4.51 and 4.87 million square kilometers, while individual forecasts range from 3.12 and 5.30 million square kilometers. We note the lowest forecast is an outlier, and the only forecast that predicts a new record September sea-ice extent value (current record is September 2012, with a sea-ice extent of 3.57 million square kilometers).

Continue reading Facts About the Arctic in August 2023 →

Facts About the Arctic in July 2023

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After briefly being near the bottom of the historical range at the beginning of the month, AWI’s high resolution AMSR2 area metric is now back near the top of that range:

However, although it’s not visible on the area graph extent has recently taken a bit of a tumble:

Here’s an animation showing the motion of sea ice in the Arctic over the last month:

Continue reading Facts About the Arctic in July 2023 →

Facts About the Arctic in August 2022

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We’ll start the new month in traditional fashion. Here’s the high resolution AMSR2 sea ice extent and area:

Extent decline in July proved to be somewhat sluggish by recent standards. A week ago I posed the question:

Is 2022 more likely to follow the path of 2012, 2013 or 2016 to this year’s minimum?

At the moment the answer seems to be “2013 Jim!”. However what about the condition of all that ice? Here’s the latest AMSR2 concentration map:

Continue reading Facts About the Arctic in August 2022 →

The 2021 Arctic Sea Ice Minimum Extent

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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 Extent →

The 2020 Arctic Sea Ice Minimum Extent

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I’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 Extent →

Facts About the Arctic in July 2020

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The new month starts with JAXA extent “lowest for the date in the satellite record” by a whisker:

The high resolution Arctic sea ice area and extent graphs based on the University of Hamburg’s AMSR2 concentration data are also in “statistical ties” for that honour, in records going back to 2013:

The 2020 melting season currently seems to be a game of two (geographical) halves. The sea ice on the Siberian side of the Arctic is currently at record lows:

Whereas the Beaufort Sea is near a record high:

Currently the tell tale signs of surface melt are visible across most of the central Arctic, as are the large number of wildfires across Arctic Siberia:

NASA Worldview “false-color” image of the Arctic on July 1st 2020, derived from the MODIS sensor on the Terra satellite

[Edit – July 4th]

The June 30th PIOMAS gridded thickness numbers have been released, and here are the results of Wipneus’s number crunching:

This month including a visualisation of the increasing negative anomaly:

[Edit – July 6th]

A break in the clouds over the North Pole reveals the onset of surface melt:

NASA Worldview “false-color” image of the North Pole on July 6th 2020, derived from the MODIS sensor on the Terra satellite
NASA Worldview “false-color” image of the North Pole on July 6th 2020, derived from the MODIS sensor on the Terra satellite

[Edit – July 8th]

After a brief hiatus there are once again some ice mass balance buoys installed at assorted locations across the Arctic. Some have ceased to function, but one of the buoys installed as part of the MOSAiC expedition is still sending back data as it heads towards the Fram Strait. Buoy 387850 is currently located at 81.66 N, 4.19 E. Here’s its ice mass balance plot:

As you can see, both surface and bottom melt are well under way, with just over a meter of ice still remaining.

Now let’s take a look at buoy 386840, currently located at 74.30 N, 132.60 W in the Beaufort Sea:

It looks as though the ice thickness has increased, but surely that can’t be right at this time of year? To try and find out I downloaded the raw data and plotted the temperature readings from the buoy’s thermistor string:

It looks to me as though the ice floe carrying the buoy is currently floating on some warm fresh water from a recently drained melt pond, which is confusing the sensor designed to measure the position of the bottom of the ice. There certainly seems to be far less than the claimed “1.653 m snow and ice thickness” still remaining to be melted!

[Edit – July 15th]

A very unusual image. Hardly a cloud in the sky over the North Pole yesterday:

NASA Worldview “false-color” image of the North Pole on July 14th 2020, derived from the MODIS sensor on the Terra satellite

The July 2020 extent “plummet” shows no signs of ending just yet. Here’s the JAXA/ViSHOP version:

[Edit – July 17th]

JAXA AMSR2 extent is now below 7 million km², and the high resolution version is lower still:

As the “Laptev Bite” and the Atlantic periphery of open water extends further towards the North Pole, Central Arctic Basin extent is now also at record lows for the date in the AMSR2 record:

[Edit – July 19th]

Wipneus has crunched the mid month PIOMAS gridded thickness numbers, and here are the results:

Extent is currently lowest in the satellite era by a long way, but modelled volume is only fourth lowest!

Watch this space!

[Edit – July 21th]

At long last there’s a sub 1000 hPa MSLP low pressure area slowly wending its way across the central Arctic:

It seems to have bottomed out at 997 hPa. Perhaps this will inhibit the ongoing “plummet” in extent? JAXA extent fell by 114,342 km2 yesterday.

[Edit – July 23rd]

The Northern Sea Route has opened unusually early this year:

Based on the AMSR2 concentration maps from the University of Hamburg that happened on July 13th. The final choke point, as is so often the case, was the Vilkitsky Strait. According to the charts from the Russian Arctic and Antarctic Research Institute, by the 14th there was a narrow way through occupied by no more than 3/10 concentration ice:

[Edit – July 25th]

A mere three days away, and the GFS and ECMWF forecasts are in agreement, so there is a decent chance this setup will materialise in the real world:

Graphics via Tropical Tidbits

A 972(ish) hPa MSLP cyclone sitting over the ice Beaufort Sea by 12Z on Tuesday.

[Edit – July 27th]

The Sea Ice Prediction Network July forecast for this year’s September minimum extent have been released. Here’s the graphical overview:

This year’s median projected value from the July forecasts of 4.3 million square kilometers is essentially identical to the median from the June forecasts. Quartiles are 4.1 and 4.6 million square kilometers. As was also the case for June, only two projections, both by dynamic models, are for a new record low, below the mark of 3.57 million square kilometers set in 2012. One dynamical model predicts the September sea-ice extent above 5.0 million square kilometers, compared to two in the June report.

Note that the numbers quoted are for the average NSIDC extent across the month of September, not the lowest daily JAXA extent, which I suggested earlier would be “below 4 million km²” this year.

Meanwhile over on Twitter this evening (UTC):

[Edit – July 28th]

The MSLP of the (Great?) Arctic cyclone sank below 970 hPa overnight:

Here’s an early false colour snapshot of how (s)he looks from on high this afternoon (UTC), courtesy of the MODIS instrument on the Terra satellite:

[Edit – July 29th]

First up today we have a more complete “true colour” image of the cyclone doing its worst yesterday, including a fairly clear view in the bottom left corner of the initial damage to the sea ice covering the eastern Beaufort Sea. This one is from the Aqua satellite:

Watch this space!