The 2024 melting season

[binntho]

Thanks, binntho, for your information. 

Some years, we know (from an A-Team gif some years ago) ice near the North Pole reaches Fram Strait in six months, a distance of nearly 800 km - so it moved, on average, a bit more than 4 km/day.

What moves the ice? Choices include wind, currents, tides, coriolis effect, aliens; I suspect wind and currents dominate.  If wind is a net neutral (i.e., random), that leaves currents.  Am I missing something (or use bad assumptions)?

Since there is no known current going from the North Pole to the Fram strait, the only option is wind. Four km per day is a very low average speed, less than 170 m/hr. But then the wind keeps changing, sending ice first one way and then another, with probably an average vector pointing south.

[binntho]

Atlantic side will receive some beating  coming days, too late for ice to recover from this. Late April is very unusual time for storm

https://zoom.earth/maps/wind-gusts/#view=79.2,46.2,4z/date=2024-04-22,08:00,+2/model=icon

This certainly looks like quite a big push of warm strong wind over several days, which will probably play havoc with the Barent Sea front and into the Kara. According to Nullschool, from the 24th a large high-pressure area will begin to form over the Beaufort, growing to cover most of the Arctic ocean by the 26th, with another smaller high-pressure settling over Greenland (again!). Is this the famous bi-pole?

We are moving into the preconditioning phase, where the amount of sunlight is most important. Meltponding early in the season is a very strong indicator for what is to come. A large high pressure area is certainly good for sunlight, not so good for the ice.

[El Cid]

I find the situation on the Beaufort side much more interesting. According to ECMWF from Apr 25/26 a huge high pressure dome is going to be above the Central Arctic/Beaufort Area. Lots of sunshine I guess

[Paul]

I find the situation on the Beaufort side much more interesting. According to ECMWF from Apr 25/26 a huge high pressure dome is going to be above the Central Arctic/Beaufort Area. Lots of sunshine I guess

Might be but it's a cold high so there won't be any melt ponds forming and the sun is probably not all that strong even at this time of year.

The basin melting season never really starts until after mid may really.

[uniquorn]

I find the situation on the Beaufort side much more interesting. According to ECMWF from Apr 25/26 a huge high pressure dome is going to be above the Central Arctic/Beaufort Area. Lots of sunshine I guess

https://www.cryosphereinnovation.com/data recently provided deployment data for the 9 drifting Beaufort buoys and the ice at deployment was thinner than the default estimates. Buoy temperature data may confirm the increases noted below. Too busy right now.

SIMB3 2024B
Ice Thickness 132cm increased to 145cm
Snow Depth 7cm no increase
Ice TypeFYI
Thickest FYI visible in area. Low snow on level ice at deployment site. Some drifting on ridges nearby.

SIMB3 2024C
Ice Thickness 132cm increased to 141cm
Snow Depth 18cm increased to 24cm
Ice TypeMYI
MYI with hummock inclusions, but not particularly thick. Appears to have nearly melted out with most of the ice thickness drilling as if it were saline FYI. Selected thickest ice apparent in the region.

SIMB3 2024D
Ice Thickness 120cm increased to 133cm
Snow Depth 5cm unsure of change
Ice TypeFYI
Large flat pan of undeformed FYI with little snow. Frost flower bumps still visible. Apparently thickest ice in area.

SIMB3 2024E
Ice Thickness 132cm  increased to 142cm
Snow Depth 15cm no increase
Ice TypeFYI*
Buoy is almost certainly in FYI, but the larger floe has a few MYI hummock inclusions.

SIMB3 2024F
Ice Thickness 101cm increased to 115cm
Snow Depth 9cm
Ice TypeFYI
Large flat pan of undeformed FYI with little snow. Appears to be thickest ice here despite being surprisingly thin, with little snow cover.

SIMB3 2024G
Ice Thickness 119cm increased to 128cm
Snow Depth 17cm no increase
Ice TypeMYI
Surprisingly thin MYI. FYI adjacent at landing site was 95 cm with little to no snow. MYI has some snow ~15cm avg.

SIMB3 2024H
Ice Thickness 102cm increased to 118cm
Snow Depth 2cm no increase
Ice TypeFYI
FYI with no snow. Appears to be full-winter ice, and is surprisingly thin. Especially with no snow cover.

SIMB3 2024I
Ice Thickness 109cm increased to 116cm
Snow Depth 22cm unsure of change
Ice TypeMYI
Surprisingly thin MYI. Adjacent FYI is about the same thickness, with less snow.

[Freegrass]

Latest Five Day Forecast + Last 5 Days
Wind + Temp @ Surface
Large GiFs!

I haven't made one of these for a long time. I almost forgot how to do it. 
But the weather is interesting now, with a lot going on, like night and day starting to matter more, and the deep cold vanishing.

Also notice the high pressure settling in at the end and the first positive temperatures coming in on both sides.

I'll let the animation speak for itself, coz I've never been good commenting on these.

[HapHazard]

The phrase "surprisingly thin" appears too often for my liking.

[kiwichick16]

daylight increasing at Barrow   Alaska

https://www.timeanddate.com/sun/@5880054

[Jim Hunt]

The ice at deployment was thinner than the default estimates.

The unusually thin MYI is confirmed by CryoSat-2:

https://GreatWhiteCon.info/2024/04/facts-about-the-arctic-in-april-2024/#Mar-18

The familiar arm of "old ice" in the Beaufort Sea is invisible on the thickness map:

[binntho]

I find the situation on the Beaufort side much more interesting. According to ECMWF from Apr 25/26 a huge high pressure dome is going to be above the Central Arctic/Beaufort Area. Lots of sunshine I guess

Might be but it's a cold high so there won't be any melt ponds forming and the sun is probably not all that strong even at this time of year.

The basin melting season never really starts until after mid may really.

Somebody put forward a formula (can't remember who ... if it was me then I must have stolen it from somebody else!) of what kind of conditions at any one time during spring/summer would maximise melt. I seem to remember the formula calling for cloudy and "mild" weather early spring, followed by intense sunlight May/June and into July, followed by stormy and windy in August/September.

The worst that can happen this early in the melting season is for the surface to start forming a crust, particularly where it is covered with loose snow which has the highest albedo. A crust is caused by partial melt of the surface at some point - which might happen in southern Beafort and the Bering this coming week, at least judging from Nullschool. I have seen crust forming on snow in sunlight even if the temperature was well below freezing, probably through some sort of sublimation.

Insolation at 70N (northern coast of Alaska) is getting into stride, but the 80/90N insolation is still lagging. The following graph from an old post by Gerontocrat is perhaps worth revisiting:

[Bardian]

" I have seen crust forming on snow in sunlight even if the temperature was well below freezing, probably through some sort of sublimation."

-10 C or warmer and sublimation starts north of 78 degree this time of spring(already midnight sun), worst for the ice now is to loose the snow cover

[gerontocrat]

SATs in the Arctic have been somewhat chilly since mid-March

Total sea ice area in the Arctic is currently 19th lowest in the 46 year year satellite record, 40th lowest (7th highest) in the High Arctic, 15th lowest in the Peripheral seas.

Graphs from Steven @ https://sites.google.com/view/arctic-sea-ice/home/temperature?authuser=0 refer to "Slater's Area"

[The Walrus]

I find the situation on the Beaufort side much more interesting. According to ECMWF from Apr 25/26 a huge high pressure dome is going to be above the Central Arctic/Beaufort Area. Lots of sunshine I guess

Might be but it's a cold high so there won't be any melt ponds forming and the sun is probably not all that strong even at this time of year.

The basin melting season never really starts until after mid may really.

Somebody put forward a formula (can't remember who ... if it was me then I must have stolen it from somebody else!) of what kind of conditions at any one time during spring/summer would maximise melt. I seem to remember the formula calling for cloudy and "mild" weather early spring, followed by intense sunlight May/June and into July, followed by stormy and windy in August/September.

The worst that can happen this early in the melting season is for the surface to start forming a crust, particularly where it is covered with loose snow which has the highest albedo. A crust is caused by partial melt of the surface at some point - which might happen in southern Beafort and the Bering this coming week, at least judging from Nullschool. I have seen crust forming on snow in sunlight even if the temperature was well below freezing, probably through some sort of sublimation.

Insolation at 70N (northern coast of Alaska) is getting into stride, but the 80/90N insolation is still lagging. The following graph from an old post by Gerontocrat is perhaps worth revisiting:

I think that is quite accurate binntho.  Clear skies this early in the season results in cold nights, and the top layer of snow forms that crust.

[Sublime_Rime]

Somebody put forward a formula (can't remember who ... if it was me then I must have stolen it from somebody else!) of what kind of conditions at any one time during spring/summer would maximise melt. I seem to remember the formula calling for cloudy and "mild" weather early spring, followed by intense sunlight May/June and into July, followed by stormy and windy in August/September.

It looks like mild weather is in store for much of the arctic for the next 7 days, except the Beaufort (where it kicks in towards the end of that period, if forecast can be trusted that far out). But Bering, CAB and Barents, especially the latter, getting above average temps. Above freezing for Bering and penetrating even up to 90N in a few days.

[Renerpho]

The phrase "surprisingly thin" appears too often for my liking.

The unusually thin MYI is confirmed by CryoSat-2

See, people are always willing to find new synonyms for old concepts.

[Carex]

On The Margins.  The Great Lakes are completely ice free.  Although it could be -10c tomorrow night, causing a minor set back.

[John_the_Younger]

there won't be any melt ponds forming and the sun is probably not all that strong even at this time of year.

and

I have seen crust forming on snow in sunlight even if the temperature was well below freezing, probably through some sort of sublimation.

With a month of always under 10F (-12C) temperatures, I've watched what sunshine-induced sublimation looks like: snow turns to grainy ice and some (maybe 10 or 20%?) of that ice 'disappears.'  I imagine grainy ice focuses (bends) light in a way to support later melting when the temperatures are circa 0C. (When looking at that grainy ice, it appears as a mixture of whites and grays (greys?), and I suspect this is caused by refraction of light.)

[Freegrass]

Latest Five Day Forecast + Last 48h
Wind + Temp @ Surface
Large GiF!

I had to make another one today, coz things are getting interesting.

A lot can, and will most definitely change in the next 5 days, but if this HPS does manage to get more powerful, the high Arctic melting season could come early this year.

-0.4°C is above the melting point of sea ice, so will we see the first signs of melt? Or will the snow and ice temperature protect the ice a little longer?

We'll definitely see the first melt in the Chukchi sea if this holds.

[El Cid]

In the past few months AI based weather forecasting systems surpassed physical systems, eg. the AI based forecasting system of ECMWF (called AIFS) is now better than the official forecast (see attachment 1).

That's why I now mostly look at the AIFS forecast and the similar AI based Graphcast model (also available from ECMWF's page)


Both of these systems show a HP system (almost) all over the Arctic as far as the forecasts go (10 and 15 days). The official ECMWF forecast shows the same (attachment 2 shows T+8 days as an example). There could be lots of clear skies over the Arctic.






ECMWF AIFS charts:

https://charts.ecmwf.int/products/aifs_medium-z500-t850?base_time=202404231200&projection=opencharts_europe&valid_time=202404231200



 

[Paul]

Latest Five Day Forecast + Last 48h
Wind + Temp @ Surface
Large GiF!

I had to make another one today, coz things are getting interesting.

A lot can, and will most definitely change in the next 5 days, but if this HPS does manage to get more powerful, the high Arctic melting season could come early this year.

-0.4°C is above the melting point of sea ice, so will we see the first signs of melt? Or will the snow and ice temperature protect the ice a little longer?

We'll definitely see the first melt in the Chukchi sea if this holds.

It's a cold high so even if temperatures do get near the freezing point in parts, it will be brief and be quite isolated in nature. Temperatures will still drop at certain times to well below freezing so no we are extremely unlikely too see any melt ponds.

Also from what I'm seeing, even if this set up occurs in late May or early June, an arctic basin high might be better for the ice as it brings very minimal heat from the landmasses, the sun at the pole whilst could shine all day is not all that strong(as far as I'm aware) and there will be troughing at lower latitudes of the basin keeping it cooler and cloudier here.

High pressure is bad for the ice if it's a ridge from the landmasses bring warmth from the landmasses which melts and pushes sea ice away from the coasts and raising sea temperatures.

[Michael Hauber]

What we could see, especially in week 2 of the forecast, is temps rising to just below freezing over large areas of Arctic.  Not warm enough to melt anything much, but no longer cold enough to freeze ice over.  Accounting for Ekmann transport towards the center of the high this may see the Laptev start to open up.  Another one to watch is Beaufort.  There has been recent dispersion in Beaufort with areas of thin new ice forming in the leads.  This could melt out quickly again if it doesn't get much cold weather in next week or so to thicken up.  The high pressure will transport ice out of the Beaufort towards Chukchi/ESS.  However in first week it probably transports just as much ice from just north of CAA westward into Beaufort with low pressure over CAA.  Week two sees high pressure over CAA so transport out towards Chukchi/ESS continuing, and transport in from north of CAA slowing/stopping.  Both weeks currently have the coldest conditions towards Beaufort so potential to further thicken up the freshly formed ice in the leads.

[binntho]

Also from what I'm seeing, even if this set up occurs in late May or early June, an arctic basin high might be better for the ice as it brings very minimal heat from the landmasses, the sun at the pole whilst could shine all day is not all that strong(as far as I'm aware) and there will be troughing at lower latitudes of the basin keeping it cooler and cloudier here.

High pressure is bad for the ice if it's a ridge from the landmasses bring warmth from the landmasses which melts and pushes sea ice away from the coasts and raising sea temperatures.

And again with heat from the landmasses. I don't know where this comes from. The Arctic receives heat from the oceans all year round, specifically from anticyclones coming up the Atlantic. During summer, the sun is by far the biggest cause of heat entering the Arctic.

In fact, being (almost) surrounded by continental landmasses is one of the main causes for the Arctic freezing almost totally over during winter. Heat transfer from the surrounding landmasses happens only once all snow has melted out, and even then is extremly limited.

Other factors that can cause melt are strong winds, but the Arctic is one of the least windy places on earth.  Oceanic heat transfer from below has big potential but happens very slowly most of the time, seeing as how the waters of the Arctic are some of the most sluggish on the planet. The Arctic truly is the Doldrums.

A few posts back I posted an insolation graph for the surface, but it only "starts" in 50N. The following chart shows insolation at top of atmosphere but compares the equator also. Peak insolation in the Arctic is quite significant, even if shortlived.

[Paul]

Also from what I'm seeing, even if this set up occurs in late May or early June, an arctic basin high might be better for the ice as it brings very minimal heat from the landmasses, the sun at the pole whilst could shine all day is not all that strong(as far as I'm aware) and there will be troughing at lower latitudes of the basin keeping it cooler and cloudier here.

High pressure is bad for the ice if it's a ridge from the landmasses bring warmth from the landmasses which melts and pushes sea ice away from the coasts and raising sea temperatures.

And again with heat from the landmasses. I don't know where this comes from. The Arctic receives heat from the oceans all year round, specifically from anticyclones coming up the Atlantic. During summer, the sun is by far the biggest cause of heat entering the Arctic.

In fact, being (almost) surrounded by continental landmasses is one of the main causes for the Arctic freezing almost totally over during winter. Heat transfer from the surrounding landmasses happens only once all snow has melted out, and even then is extremly limited.

Other factors that can cause melt are strong winds, but the Arctic is one of the least windy places on earth.  Oceanic heat transfer from below has big potential but happens very slowly most of the time, seeing as how the waters of the Arctic are some of the most sluggish on the planet. The Arctic truly is the Doldrums.

A few posts back I posted an insolation graph for the surface, but it only "starts" in 50N. The following chart shows insolation at top of atmosphere but compares the equator also. Peak insolation in the Arctic is quite significant, even if shortlived.

I'm sure I read elsewhere the suns strength at the pole even at the peak is not as strong as one would imagine. Infact when Zack Labe posts his graphics for the suns strength at the solstice, it seems to suggest the further south you go the stronger the suns strength is.

Heat from landmasses has to be main contributor for ice lost, having temperatures of over 25C let's say blowing across the ice and whilst the air temperature quickly cools as it goes over the ice it's still usually above freezing hence the melt ponds start.to form. The sun at the beginning of the melt season usually gets reflected back from snow cover although of course any sun over open water will heat it up.

[binntho]

I'm sure I read elsewhere the suns strength at the pole even at the peak is not as strong as one would imagine. Infact when Zack Labe posts his graphics for the suns strength at the solstice, it seems to suggest the further south you go the stronger the suns strength is.

Well imagine that, "not as strong as one would imagine" and "the further south you go the stronger the suns strength is".

Heat from landmasses has to be main contributor for ice lost, having temperatures of over 25C let's say blowing across the ice and whilst the air temperature quickly cools as it goes over the ice it's still usually above freezing hence the melt ponds start.to form. The sun at the beginning of the melt season usually gets reflected back from snow cover although of course any sun over open water will heat it up.

No, heat from the landmasses does not have to be a "main contributor for ice lost [sic]" - most of the year, the landmasses are covered with snow for hundreds of kms and all of this has to melt (by the sun!) before any heat could concievably get from the landmasses to the Arctic ocean.

And even when, as does happen on occasion, hot winds blow in over the Arctic from Siberia or Canada, the heat transfer from a warm air mass to the ice is surprisingly low without moisture, turbulence and strong wind, most of which are normally missing. And it is simply not that common for this to happen, and not nearly common enough (or early enough) to have any substantial effect on meltponding.

Met ponds form primarily from solar activity, and they form typically under high-pressure domes with lots of sunshine and temperatures around freezing, once open fresh-water exists the air temperatures will hover around 0C.

The following scientific paper is quite good for understanding these things:

Arctic sea ice melt onset favored by an atmospheric pressure pattern reminiscent of the North American-Eurasian Arctic pattern

"A major catalyst of early melt onset is increased downwelling longwave radiation, associated with increased levels of moisture in the atmosphere. "

"The dominant moisture transport to much of the Arctic is enabled by a broad low pressure region stretching over Siberia and a high pressure over northern North America and Greenland. This configuration ... funnels moisture from lower latitudes and through the Bering and Chukchi Seas."

According to this paper, melt onset varies from middle to end of May. The Northern Siberian coast is still below freezing at this time of year, and not before July do you get temperatures averaging above 10C. (Nizhneyansk)

On the Canadian coast the temps are ever so slightly milder, but average is still below freezing in May, and temperatures above 10C possible in June. (Tuktoyaktuk)

Just from these numbers, with melt onset in the Arctic itself being a month ahead of below-freezing temperatures in the surrounding coastal areas, this idea of "heat from the landmasses" is doomed.

[oren]

High pressure domes can cause significant melt later in the season. However in late April and early May more significant preconditioning would be by winds from the south bringing heat and moisture, such as is available which is not much for obvious reasons.
Still the best (worst) preconditioning at this time of year is continued export down the Fram, especially with most of the thick ice stuck in the vicinity of the Pole and below.

[Paul]

High pressure domes can cause significant melt later in the season. However in late April and early May more significant preconditioning would be by winds from the south bringing heat and moisture, such as is available which is not much for obvious reasons.
Still the best (worst) preconditioning at this time of year is continued export down the Fram, especially with most of the thick ice stuck in the vicinity of the Pole and below.

As I said, it's the type of high pressure system that could be significant also, a basin high might not be too damaging for the ice as it's not bringing much warmth from the lower latitudes and it could help the ice compact together so less dispersion. A high pressure ridge from lower latitudes could bring warmth and mixed in with a low pressure system could bring rainfall also

I'll stand by at every melt season that high pressure is bad for ice and low pressure is good for ice is too simplistic especially these days where low pressure can cause significant dispersion of the ice.

[Freegrass]

High pressure domes can cause significant melt later in the season. However in late April and early May more significant preconditioning would be by winds from the south bringing heat and moisture, such as is available which is not much for obvious reasons.
Still the best (worst) preconditioning at this time of year is continued export down the Fram, especially with most of the thick ice stuck in the vicinity of the Pole and below.

The thing with moisture is that it instantly turns into snow in cold air. The recent event over the Fram was different, because it briefly raised temperatures above freezing temperatures. But this was short-lived and will have minimal impact for the rest of the season beyond pushing back the ice a little.

A similar situation will occur over the Chukchi Sea in the coming days. Warm, moist air from the Pacific Ocean will enter through the Bering Strait, raising temperatures above freezing and preconditioning the ice. Which will have a lasting effect.

Low-pressure systems (LPS), also known as cyclones, bring in heat from southern latitudes, or chase away the cold as I sometimes like to say it. Currently, this primarily raises temperatures and brings additional snow, but it won’t significantly precondition the ice for melting. In fact, the snow may increase the ice’s albedo.

This situation will change rapidly in the coming weeks, as temperatures continue to rise. Especially on the Pacific side.

However, for now, the ice should still be thickening. If temperatures continue to rise, that won't happen anymore.

If we do experience a massive high-pressure system (HPS), I’m curious to see its impact. Will temperatures become positive in certain areas? LPS's like to hang around the edges of HPS's.

Could there be a ridge like the long term forecast predicts? That would definitely bring in loads of heat. Time will tell.

And Oren is right, large HPS systems can export significant amounts of ice through the Fram Strait.