The 2018 melting season

[Steven]

Land snow cover extent for April 2018 was 1.84 million km² above average.  It's similar to years like 2017 and 2013.




https://climate.rutgers.edu/snowcover

[Daniel B.]

2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

[numerobis]

2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.

[bbr2314]

2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.

Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?

[binntho]

2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.

Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?

Well, pine and spruce never have leaves.

[bbr2314]

2017 and 2013 where years which saw a significant increase in sea ice minimum over the preceding year.

1994 had a fair bit more ice than either 1995 or 1996, both of which had high snow cover anomalies. So your correlation doesn't check out well.

The northern hemisphere is very large compared to the Arctic. Most of the snow cover anomaly is in mid latitudes, under trees -- and is gone by early to mid May. I'm completely unconvinced there's any link at all with the ice.

Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?

Well, pine and spruce never have leaves.

You can merely have an ass or you can actively be one.



This notion that "trees mitigate snowcover" is literal horsesh*t. It is ignorance at best and dishonest at worst. If you want to talk about different kinds of leaves then the melting thread is not for you.

[gerontocrat]

Is there historical data on snow on the treeless far north to the ocean edge of Canada and Russia? If snow persists there longer is it not there that an effect on the sea ice is more likely?

[Dharma Rupa]

Normally when there is extant snow cover trees don't have leaves, but maybe you don't live in a place where it snows?

Normally, trees in areas that snow a lot are evergreens.

[binntho]

Well, a quick look at the literature shows that snow over no-shrub tundra has the highest albedo, but also melts out much faster come spring. With increased vegetation, from dwarf shrub to low shrub to conifer forests, albedo drops significantly.In April (with snow cover), boreal forests have albedo of around 0.4, tree-shrub-mosaic tundra about 0.5, and other types of tundra between 0.72 and 0.76. Fresh snow has albedo of 0.8-0.9.

On longer timescales, since boreal forests and shrub cover is rapidly moving northwards, one would expect the effects of snow cover on albedo to drop as well.

Nowhere in the literature did I see any mention of asses or horses**t.

[litesong]

Land snow cover extent for April 2018 was 1.84 million km² above average.  It's similar to years like 2017 and 2013.




https://climate.rutgers.edu/snowcover

Your North American charts are interesting. Comparing our small Washington state region is apples & oranges, but the 98-99 season at Mt. Baker, WA set the world snowfall record at 1140 inches. Previous to that, Mt. Rainier, WA had world snowfall record at 1122 inches. Half way between Baker & Rainier about 5-7(?) years ago, Skykomish, WA (in the mountains, but only 1200(?) foot elevation had snows that were 11 feet of snow in yards. Residents, while on their roofs trying to clear snows, had to pitch shovelfuls of snow.... upward to be able to clear the snows in their yards.   

[gerontocrat]

This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

I thought this thread was for the melting season.

But since you are all at it - I did a post today on the "Northern hemisphere snow cover" thread which included the following:-

Trends and Extremes in Northern Hemisphere Snow Characteristics
Abstract
Recent studies of snow climatology show a mix of trends but a preponderance of evidence suggest an overall tendency toward decreases in several metrics of snow extremes. The analysis performed herein on maximum seasonal snow depth points to a robust negative trend in this variable for the period of winter 1960/1961–winter 2014/2015. This conclusion is applicable to North America. Maximum snow depth is also mostly decreasing for those European stations analyzed. Research studies show generally negative trends in snow cover extent and snow water equivalent across both North America and Eurasia. These results are mostly, but not fully, consistent with simple hypotheses for the effects of global warming on snow characteristics.

ps: I want to see here all the really good stuff on what is physically happening to the ice in the Arctic.

[jdallen]

This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

<snip>

Shifting the discussion to there.

https://forum.arctic-sea-ice.net/index.php/topic,292.msg152440.html#msg152440

[RoxTheGeologist]

This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

<snip>

Shifting the discussion to there.

https://forum.arctic-sea-ice.net/index.php/topic,292.msg152440.html#msg152440

Good idea, as it looks like the North Pole might be getting a spot or two of rain by the end of the week.

[romett1]

Good idea, as it looks like the North Pole might be getting a spot or two of rain by the end of the week.

I agree - current models are showing that this heat is staying for quite a long time. And Morris Jesup weather station shows already 0 °C, that is jump from -19 °C. Image: http://www.dmi.dk/groenland/maalinger/vejret-lige-nu/stations/vis/4301

[oren]

Thanks for the link Romett1. For some reason the whole "current weather" part does not exist in the English version of the DMI/Greenland website.

[FishOutofWater]

In mid-February the NH had the most intense stratospheric warming on record as far as i know. The sudden stratospheric warming in mid January 2013 was very powerful. in 2017 the end warming went out with a huge pulse of heat to the upper stratosphere. Following these warmings momentum was transferred downwards causing the polar jet to expand southwards. All of these years had greater than average NH snow amounts and cool spring weather in the eastern U.S. and western Europe.

If you go back in the climate records you will find that strong stratospheric warmings are associated with the kind of weather we have seen since mid February. I'm not convinced, however, that this summer will be like summer 2013 because the effect of SSWs does not appear to last beyond one season.

Moreover, this year the north Atlantic overturning circulation in the Labrador sea appears to be much stronger than it was in 2013. Warm salty water has been pulled back up onto the the north side of the subpolar gyre in the Labrador sea, then cooled and mixed down to 2000m. Right now there's a burst of heat being released to the air above the far north Atlantic building an atmospheric ridge over norther Europe.

The net result is that the Arctic ice pack on the Atlantic side will be taking a hit over the next week.

[epiphyte]

This thread is getting snowed under  - again. There is a thread called - Northern hemisphere snow cover, there is a thread called - Land snow cover effect on sea ice.

<snip>

Shifting the discussion to there.

https://forum.arctic-sea-ice.net/index.php/topic,292.msg152440.html#msg152440

Good idea, as it looks like the North Pole might be getting a spot or two of rain by the end of the week.

Rain? Rain, I ask you?
Please don't anyone say rain is off topic. That would (also) be very, very, silly.

PS. Got your fickle NH snow cover anomaly right here... My front lawn. April 15 vs May 01 2018
It's 2018. It's melting. It's the season for that.

ergo... It's on topic.

[JayW]

102 hours loop April 27- May 1, Beaufort and some Chukchi.  Looks like most of the fast ice NE of Alaska has sheared away.  The Chukchi isn't freezing over anymore, at least the southern part, but low clouds ( likely due to the open water) are obscuring things.  The Beaufort is freezing over the leads opened up by the winds.

Contrast slightly increased for detail

http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?page=4&search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1

[jdallen]

I doubt the Beaufort leads will refreeze much past 10-20CM. That fragmentation is bad news.

[Shared Humanity]

As a gardener, I've always loved early spring snowfalls. The melting snow would seep into the ground and guarantee a healthy, early summer harvest.

[litesong]

This thread is getting snowed under  - again.....I thought this thread was for the melting season.

The more snow that falls, means all the more snow that melts(never becoming hard ice?), under warming AGW conditions. 

[Alexander555]

A little heat moving in.

[uniquorn]

Ice lifting off the nth Greenland coast already.
Worldview terra/modis Apr30-May2

[uniquorn]

Comparison with previous years on May2 2007-2018

[gerontocrat]

The warmth heading up off the East Coast of Greenland is beginning to affect temperatures at 80+ North, and look to increase somewhat for a week or so. Warmer than 2017 by about 3 degrees at 2nd May.

Will the high Arctic be warmer than 2017? We are reaching the time of year when it matters.

[Dharma Rupa]

The warmth heading up off the East Coast of Greenland is beginning to affect temperatures at 80+ North, and look to increase somewhat for a week or so. Warmer than 2017 by about 3 degrees at 2nd May.

Will the high Arctic be warmer than 2017? We are reaching the time of year when it matters.

Thanks for the vertical lines....they are so much better than my eyes -- and I was pretty sure I was seeing hotter than last year.

[gerontocrat]

Thanks for the vertical lines....they are so much better than my eyes --

I am selfish - I did it for me but am glad others find it helpful. 

[litesong]

Will the high Arctic be warmer than 2017? We are reaching the time of year when it matters.

When the sun is low on (or below) the High Arctic horizon, the everyday (fall, winter, & early spring?) weather of the High Arctic daily line gradually has been rising since 1958(before?), due to the increasing predominant AGW excess GHG heat(& positive feedbacks) building in Earth's biosphere. This effect has continued despite the Total Solar Irradiation decrease for the last 11+ years(including a 3+ year period with the TSI setting a 100 year record low). However, when the sun is not so low & high off the High Arctic horizon for as much as 24 hours per day, the TSI, low for the last 11+ years, is causing High Arctic summer temperatures to average slightly below the 1958-to-present average temperature.
It is remarkable that the "dark" season of the High Arctic is countering the low TSI. If the low TSI continues (or drops further) for decades(?), only the increasing strength of AGW GHG heat, can keep the High Arctic "dark" season from dropping.       

[Neven]

On-topic, please.

[Neven]

Here are the 925 hPa temperature graphs for April. Arctic overall was 5th lowest highest on record, Atlantic was 10th, Siberian was 15th, Pacific was lowest highest, Canadian was 23rd lowest highest on record:

[Neven]

The current ECMWF weather forecast is very interesting as well. Aside from the heat coming in via the Atlantic, it seems that if the high pressure can't be over the CAB, it shifts on the periphery, looking for a way to get back in. In this case it forms a ridge of sorts from the Kara Sea to Alaska. It's May now. This should slowly start having an impact, even if imperceptible at first.

[slow wing]

Here are the 925 hPa temperature graphs for April...

Very interesting, thanks Neven! How many years are on this record?

[Neven]

Did you mean highest?

Yes, I did! Thanks, fixed now.

How many years are on this record?

1948-2018.

[Juan C. García]

Here are the 925 hPa temperature graphs for April. Arctic overall was 5th lowest highest on record, Atlantic was 10th, Siberian was 15th, Pacific was lowest highest, Canadian was 23rd lowest highest on record:

From the first graph, I see it as the 4th highest...
Are there more years that we can analyzed?

[Neven]

1995 was warmer as well, Arctic-wide (-9,354). I'll be more clear in the future that I'm referring to the 1948-2018 period, but that the graph only shows 2005-2018.

[uniquorn]

Lift off from the north Greenland coast continues. The ice front retreats a little with the warmer wind.
Worldview terra/modis May1-3

[gerontocrat]

It is getting warmer North of 80

[Juan C. García]

It is getting warmer North of 80

Just to make the comment, I am not sure to put "Like" to something that I don't like! 
But thanks for the information! 

[Neven]

Even though 80N is only a small part of the Arctic, I still regard the DMI temperature graph as somewhat indicative of what's going on, a precursor of sorts. In this sense, the current high temperatures there may prove to be significant. Emphasis on 'may'.

Below is what I would consider the most important graph in the latest NSIDC summary. According to the summary there's a record high amount of FYI and record low amount of MYI:

As averaged over the Arctic Ocean (Figure 4d), the multiyear ice cover during week nine has declined from 61 percent in 1984 to 14 percent in 2018, the least amount of multiyear ice recorded. In addition, only 1 percent of the ice cover is five years or older, also the least amount recorded. This is rather striking since September 2017 did not set a new record low minimum extent. The proportion of first-year versus multiyear ice in spring will largely depend on the amount of open water left at the end of summer over which first-year ice forms. How much ice is transported out of the Arctic through Fram Strait in winter also plays a role. The unusually high amount of first-year ice this March suggests that there was a strong Fram Strait ice export this past winter. Given that (in the absence of ridging) first-year ice grows to about 1.5 to 2 meters (4.9 to 6.6 feet) thick over a winter season, the ice age data point to a fairly thin ice cover. Nevertheless, how much ice melts out this coming summer will depend strongly on summer weather conditions.

I'm not sure how accurate this is. For instance, I'm not seeing the band of MYI extending across the Beaufort towards Chukchi. A-Team, are you reading? What do you think?

[Neven]

Here are ASCAT and AARI for around week 9:

[Neven]

Wipneus also wrote in the PIOMAS thread recently:

PIOMAS has updated the so called gice data (upto 22th of April). As some will remember, ice in each gridcell in the PIOMAS model is specified as a discrete distribution: there exist 12 categories of ice thickness (m):
[0.00, 0.26, 0.71, 1.46, 2.61, 4.23, 6.39, 9.10, 12.39, 16.24, 20.62, 25.49]
gice specifies the percentage less or equal to the thickness of each category.

From these I calculate total area occupied for each cat as shown in the attached graph.

PIOMAS has the lowest area on the 22 April of all years, but more of that ice is thicker than in some recent years.

For the time being, I'm not sure the ice age graph and map posted in the NSIDC summary are accurate, but don't have time to look into it more.

[be cause]

So the dmi 80 has got back to where it was in late Feb ! This time it will keep on going . I don't believe I have seen such anomalously warm forecasts this time of year before , and if anything like them comes to pass then wreckords may litter this season ! b.c.

[GoSouthYoungins]

Forecasts for May 6th and/or 7th look like the 80N mean temp will be a serious outlier for the 2nd time in less than 3 months.

The entire arctic seems to be similar to a barely refrozen slushy. And the Pacific and Atlantic ice edges are as close together as they have “ever” been this time of year.

The northern hemisphere’s temperature regulator appears near the precipice of a major shift. Every year in the next decade it becomes more likely to take the dive, at which time (if recent warming trends continue) it becomes inevitable irrespective of weather volatility.

With the temperature lid effectively removed, A) a drastically quicker atmospheric warming will commence, and B) immediate climate system chaos will occur.

First post. Howdy.

[Michael Hauber]

Circulation patterns for the last few months seem semi-favourable for multi-year ice retention.  The NSIDC doesn't just show a record low multi-year amount, but a very big record.  I doubt it is correct.

These circulation patterns would also help build up thicker ice in Siberian and Laptev regions (although temps would oppose this).

[Coffee Drinker]

Major torch for southern Hudson Bay in extended forecast. Far out but 30C possible to destroy the ice.
http://www.wetterzentrale.de/en/topkarten.php?map=5&model=gfs&var=5&time=384&run=18&lid=OP&h=0&tr=3&mv=0

[jdallen]

Even though 80N is only a small part of the Arctic, I still regard the DMI temperature graph as somewhat indicative of what's going on, a precursor of sorts. In this sense, the current high temperatures there may prove to be significant. Emphasis on 'may'.

Below is what I would consider the most important graph in the latest. According to the summary there's a record high amount of FYI and record low amount of MYI:
<snippage>

I'm in full consensus with you Neven.  The lack of MYI is a very big signal, and as most of that ice is under 2.5M in thickness, even a "normal" melt season could reach 2-3rd lowest extent/area/volume.

The table is set, weather is now key, and the high pressure and sunshine now hitting the Arctic from the Kara to Alaska may be very important, especially if it persists.

[bbr2314]

It looks like the impact of "no Fram" due to warmth will imminently entail the re-opening of Nares for export. Massive cracking extending towards it as of yesterday. Probably won't take much to break the arch and start early transport of MYI toward Baffin.

If model depiction of heat through D5 is correct, the transport may be more of an absolute gushing. That is... an enormous amount. The ATL front is going to be obliterated.

[subgeometer]

The 5 day anomaly forecast on GFS is pretty insane

[uniquorn]

snippage
latest NSIDC summary..ice age wk9...I'm not sure how accurate this is. For instance, I'm not seeing the band of MYI extending across the Beaufort towards Chukchi.

3 clearish days from feb28-mar2 show the string of MYI floes fairly well using viirs band15. They appear to get progressively fractured and dispersed as they make their way round the Beaufort. (maybe even bottom melt in that area?)

worldview brightness temperature band15 night
https://tinyurl.com/y7wjshaz

[romett1]

It is getting warmer North of 80

As next 7 days are really interesting north of 80 °N, it is worth looking also FDD (Freezing Degree Days) anomaly. As March was colder than in 2016 and 2017, May seems to be a lot warmer (north of 80 °N). Since start of the year 2018 is now slightly warmer than 2017 (north of 80 °N) and is probably going to chase 2016 as well. Image: https://sites.google.com/site/cryospherecomputing/fdd