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Frivolousz21

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Re: The 2015 melting season
« Reply #900 on: May 22, 2015, 06:19:25 AM »
Wow the 12z euro is bone crushing
I got a nickname for all my guns
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it go e-e-e-e-ow e-e-e-e-e-e-blaow

jdallen

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Re: The 2015 melting season
« Reply #901 on: May 22, 2015, 06:50:55 AM »
Wow the 12z euro is bone crushing
Might be associated with this image, from 171 hours out in 5/28?

Bit warm for this time of the season, maybe?

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Frivolousz21

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Re: The 2015 melting season
« Reply #902 on: May 22, 2015, 08:25:54 AM »
Yes

The 00z gfs is brutal.

If these model runs verify we are talking flying Right into June in unprecedented territory.




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it go e-e-e-e-ow e-e-e-e-e-e-blaow

Frivolousz21

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Re: The 2015 melting season
« Reply #903 on: May 22, 2015, 08:36:40 AM »
Tuktoyaktuk Canada literally on the
Shores of the arctic basin reached 77F today.

The average high is 34.5F.

The record set in 1984 was 54F.


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my TEC 9 Imma call T-Pain
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it go e-e-e-e-ow e-e-e-e-e-e-blaow

plinius

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Re: The 2015 melting season
« Reply #904 on: May 22, 2015, 11:43:59 AM »
@Jim:
Yes, I have seen satellite images. Most of the arctic (> 80%) is still covered in cold, pure, white snow, no matter if there is sunshine or not. Sunshine does not do a lot there and consistently you do not even see a trace of melt. And the parts under WLA are nicely melting under the cloud cover. Once the sun comes out, they will be ready for a nice melt, but we were talking about the onset.

@Jai:
Same applies here: Most of the arctic is not wet snow, but dry snow at this time of the year. Warm rainy weather is a phantastic environment for melt onset, as the snow is very vulnerable against downwelling long-wave, while the Sun would not do anything. If it is hard to believe, just look at obuoy 9 which has seen many days of marvellous sunshine, but the weather is so cold, that even the nearby big lead has frozen over again. Even mid May the sun does not melt ice with snow on it (major factor last year, by the way, where fresh snow played a role in moderating melt).


Solar insolation does VERY little in April and May. That's because ice is covered with snow at albedo values of 0.8-0.9, probably rather close to 0.9

You have seen the satellite images of melt ponds in May this year I take it?

jai mitchell

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Re: The 2015 melting season
« Reply #905 on: May 22, 2015, 03:11:15 PM »
@slow wing - I have only played around with the nullschool datasets I do not know the specific correlation to cloudcover or precipitation events.  I don't think that you can extract the level of detail regarding precipitation using it unless it is absolutely obvious (i.e. 25C and 100% humidity is most likely rain!).  For cloud cover if you go to NASA worldview, MODIS can show a rough correlation to cloud cover, I like to work with the 1000 hPa elevation for the arctic and TPW for cloud cover, it correlates, well, ok I guess.

compare

http://earth.nullschool.net/#2015/05/21/1200Z/wind/isobaric/1000hPa/overlay=total_precipitable_water/equirectangular=-69.88,87.24,1193

https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor%28hidden%29,MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels%28hidden%29,Reference_Features%28hidden%29,Coastlines&t=2015-05-22&v=-6553600,-3231744,6553600,3231744

click on earth and select arctic (top right)
then on left click "corrected reflectance 3-6-7
and you can see if they match up very well. 

@plinius

agreed, if it is -15C sunshine isn't going to do much, as we approach the melt season and air temperatures approach 0C (as they did in the Chukchi a few weeks ago) sunshine this early in the season is devastating to the ice.  to treat the entire ice pack as though it was the CAB is not really accurate, the melt always starts from the outside edges in mid May and moves inland until early June. 

Which is why this cloud cover is assisting the ice to remain for about 30% of the total surface area where melt and air temperatures have already driven snowmelt and is working on the ice below.

FYI the meltponds never get to 3C, the increased heat absorption due to solar insolation and reduced far spectrum IR emissivity of meltponds drives ice melt, the melt of ~1 foot per week surface is how much additional energy is absorbed by an decrease in albedo from .8 (or so) to .3
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jdallen

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Re: The 2015 melting season
« Reply #906 on: May 22, 2015, 05:18:49 PM »
FYI the meltponds never get to 3C, the increased heat absorption due to solar insolation and reduced far spectrum IR emissivity of meltponds drives ice melt, the melt of ~1 foot per week surface is how much additional energy is absorbed by an decrease in albedo from .8 (or so) to .3
Makes sense on both counts. Smaller thermal volume would be buffered more by the mass of the ice going through phase change. Under ideal conditions, the additional insolation could strip off 30 CM a day.
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plinius

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Re: The 2015 melting season
« Reply #907 on: May 22, 2015, 05:40:01 PM »
Don't understand why it is a surprise that meltponds have a maximum temperature <3 C. Convection and boundary condition on the ice surface will ensure that...

@Jai: As we agree on the -10 to -15C on the main ice mass, I think we do not need to argue that cloudy skies in May actually help trigger ice melt, if they are connected to warm, humid WLA. On sunny skies you just do not break the inversion in May, if not from the side.  And nobody has treated the pack as if it was the CAB. Just any region of interest does not normally show significant melt in May and sunny skies. That comes later (and I do not care so much about Hudson or so).

jai mitchell

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Re: The 2015 melting season
« Reply #908 on: May 22, 2015, 06:19:25 PM »
This curve shows the average temperature rates for the CAB



peripheral locations to the CAB have similar warming profiles though shifted to the left (earlier)

I stand by my previous statement that increased cloudcover in those regions at this time are helping to prevent ice loss.  This should be obvious now that there is observed melt pond formation in these regions.

Cool cloudy days covering melt ponds are doing nothing to the ice compared to warm and intense sunshine that is available under clear sky conditions.
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Siffy

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Re: The 2015 melting season
« Reply #909 on: May 22, 2015, 06:48:11 PM »
This curve shows the average temperature rates for the CAB



peripheral locations to the CAB have similar warming profiles though shifted to the left (earlier)

I stand by my previous statement that increased cloudcover in those regions at this time are helping to prevent ice loss.  This should be obvious now that there is observed melt pond formation in these regions.

Cool cloudy days covering melt ponds are doing nothing to the ice compared to warm and intense sunshine that is available under clear sky conditions.


This doesn't seem to make much sense to me.

DMI 80 models temperatures of the CAB which actually hasn't been particularly overcast the last week or so.

http://obuoy.datatransport.org/monitor#buoy9/weather

Obuoy 9 has shown relatively clear skies overall and has been to the north of greenland giving us a good view of weather conditions instiu.

In contrast buoys 10-12 have shown cloudy weather and the temperatures are far above average for the time of year.

The weather manifestly isn't cool in periphery the over the last week (On the alaskan side) and large scale onset of melt ponding is occurring. Maybe the ice isn't melting much right now I couldn't say but the snow cover over much of the pack around the Beaufort and the Chukchi has been obliterated.

I don't understand how the formation of meltponding is proof that ice loss is being reduced due to cloud cover when it seems like in a large part the cloud cover is responsible for the large drop in albedo of the surface?

Maybe I'm not understanding something you're trying to communicate though?


plinius

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Re: The 2015 melting season
« Reply #910 on: May 22, 2015, 07:00:34 PM »
I second that and would also like to add:
Boltzmann constant is 5.67*10^-8 Watts m^-2 K^-4
So the radiation loss rises by >20 Watts per every 5 Kelvin warmer surface temperatures, which is of order the same quantity as the entire absorbed insolation in that region. So, that has nothing to do with  fast rising temperatures due to sunshine, but with the region being just very cold right now and duly warming up.

Peter Ellis

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Re: The 2015 melting season
« Reply #911 on: May 22, 2015, 07:43:49 PM »
This doesn't seem to make much sense to me.

DMI 80 models temperatures of the CAB...

Not really. They use a 1/2 degree grid with all points given equal weighting, i.e. the same number of measurements at 89 degrees north as at 80 degrees north, despite the fact that the former points are much closer together.  It is thus VERY strongly weighted towards the region around the Pole itself.

http://ocean.dmi.dk/arctic/documentation/arctic_mean_temp_data_explanation_newest.pdf

Compare the DMI trace to the trace from buoy 2015D, which was placed at the Pole by the Barneo expedition and has since drifted a few degrees south.
http://imb.erdc.dren.mil/irid_data/2015D_temp.png

The DMI trace is essentially "The temperature in Santa's back garden" and doesn't say anything about wider Arctic conditions.

helorime

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Re: The 2015 melting season
« Reply #912 on: May 22, 2015, 07:46:07 PM »
Looks like Alaska is going to stay unusually warm for a while.  https://www.adn.com/article/20150521/unusual-weather-pattern-brings-record-highs-barrow
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jai mitchell

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Re: The 2015 melting season
« Reply #913 on: May 22, 2015, 07:53:39 PM »
Yes, the CAB warms at a later date than the periphery that is not in close proximity to Greenland or Baffin.  Snow cover anomalies are a primary driving force for air temp warming in the outlying regions and it is only in these areas that the insolation values have impact at this early date.

only later in the season (say 2-3 weeks) will the CAB experience significant melt-pond and solar effects.  In this way then the modeled rate of mass loss to surface area shows increasing periphery loss at the beginning and increased surface loss toward the middle-late melt season.



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Sonia

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Re: The 2015 melting season
« Reply #914 on: May 22, 2015, 11:38:32 PM »
Barrow lost some ice today.  The 1 day radar loop (at http://seaice.alaska.edu/gi/observatories/barrow_radar/recent-radar-animations) currently shows it well. 

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Re: The 2015 melting season
« Reply #915 on: May 23, 2015, 03:07:54 PM »
Near Barrow (Thanks for the link Sonia)...

If HYCOM is correct then the ice edge in the Beaufort Sea looks like it's about to hit the multi-year ice, a stall might be expected over the next week to two weeks. But there's a lot of open water there before the solstice and warming water this early in the season might be enough to seriously attack the multi year ice. I hope so, that would open up the possibility of a good low extent by September.

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Re: The 2015 melting season
« Reply #916 on: May 23, 2015, 03:39:12 PM »
As of day 141 (21 May)...

Beaufort extent is 0.494M km^2, not the lowest on record.

6 years have 21 May extent below 0.5M km^2. Of these 1982, 1998, 2008, 2012 correspond to the following September having extent that is a local minima (i.e. a drop down from the years around those years). Only 1991 saw a September extent that was a local maximum.

Examining what happened in 1991 vs those other years is left as an exercise to the reader. ;)
i.e. I can't be bothered.  :P

Anyways, this makes me a bit happier. If we don't have another re-run of the crappy weather of 2013 and 2014 then there's a good chance that ice albedo feedback started early will give us a good low extent later in the summer.  :)

Jim Hunt

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Re: The 2015 melting season
« Reply #917 on: May 23, 2015, 04:14:38 PM »
Summer seems to arrived early in the Beaufort Sea this year, so my ice mass balance buoy temperature profiles are hastily moving into summer mode:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2015-imbs/#2015A

The webcam trained on SIMB 2014A has now been righted, although the recent attentions of a polar bear seem to have broken the top sounder.

SIMB 2015E has also recently been installed north of Svalbard, although it doesn't seem to be fully "frozen in" as yet.
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Re: The 2015 melting season
« Reply #918 on: May 23, 2015, 04:14:59 PM »
As of day 141 (21 May)...

6 years have 21 May extent below 0.5M km^2. Of these 1982, 1998, 2008, 2012 correspond to the following September having extent that is a local minima (i.e. a drop down from the years around those years). Only 1991 saw a September extent that was a local maximum.

Examining what happened in 1991 vs those other years is left as an exercise to the reader. ;)
i.e. I can't be bothered.  :P

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Might just  be relevant there.
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Re: The 2015 melting season
« Reply #919 on: May 23, 2015, 04:17:53 PM »
Summer seems to arrived early in the Beaufort Sea this year, so my ice mass balance buoy temperature profiles are hastily moving into summer mode:

The webcam trained on SIMB 2014A has now been righted, although the recent attentions of a polar bear seem to have broken the top sounder:
It's wet. it sits on top of ice, it  looks like a melt pond,  or several to me.
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Nightvid Cole

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Re: The 2015 melting season
« Reply #920 on: May 23, 2015, 06:10:52 PM »
OMG!!! 06Z GFS has the entire CAB above freezing on the 29th and 30th!!!  :o

I predict the unprecedented - that by June 5th, the central Arctic will have discernible surface melt on MODIS...
« Last Edit: May 23, 2015, 06:20:11 PM by Nightvid Cole »

Shared Humanity

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Re: The 2015 melting season
« Reply #921 on: May 23, 2015, 06:31:58 PM »

Shared Humanity

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Re: The 2015 melting season
« Reply #922 on: May 23, 2015, 06:39:06 PM »
Near Barrow (Thanks for the link Sonia)...

If HYCOM is correct then the ice edge in the Beaufort Sea looks like it's about to hit the multi-year ice, a stall might be expected over the next week to two weeks. But there's a lot of open water there before the solstice and warming water this early in the season might be enough to seriously attack the multi year ice. I hope so, that would open up the possibility of a good low extent by September.

It looks as if open water is trying to surround that MYI. Could it possibly be attacked on all sides?

plinius

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Re: The 2015 melting season
« Reply #923 on: May 23, 2015, 06:50:00 PM »
that's melt pond bias and a couple of leads. Open water is something highly different...

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Re: The 2015 melting season
« Reply #924 on: May 23, 2015, 06:57:10 PM »
I must be getting old.

Which year had the midsummer cyclone that ripped apart the CAB and resulted in a very low minimum? Was that 2012?

If the ice edge in the Beaufort and Chukchi retreats north towards the pole early enough and far enough we could have a repeat as the the temperature differences at this ice edge will encourage the formation of storms.

plinius

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Re: The 2015 melting season
« Reply #925 on: May 23, 2015, 07:02:06 PM »
I know of no research paper showing conclusively that a local ice edge will encourage storms. Any meat on this?

And yes, 2012.

Metamemesis

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Re: The 2015 melting season
« Reply #926 on: May 23, 2015, 07:04:05 PM »
Add in some "dark snow" from early fires in the Yukon and NW Territories on 21 May, and that MYI is facing a multitude of high-melt factors. You can clearly see the smoke clouds heading out over the ice flows in the Beaufort between the McKenzie River delta and along to the Eskimo Lakes (at the right side of the image)


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Re: The 2015 melting season
« Reply #927 on: May 23, 2015, 07:07:12 PM »
I know of no research paper showing conclusively that a local ice edge will encourage storms. Any meat on this?

And yes, 2012.

No....not really. I'm just talking out of my ass.  ;)

I thought I did recall someone here who knows more than me (this could be anyone) say that storm formation is encouraged at boundaries between warm and cold atmosphere.

Jim Hunt

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Re: The 2015 melting season
« Reply #928 on: May 23, 2015, 09:10:14 PM »
Landsat 8 from the Western Beaufort yesterday. Around 73N, 150W:
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Siffy

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Re: The 2015 melting season
« Reply #929 on: May 23, 2015, 09:14:51 PM »
Landsat 8 from the Western Beaufort yesterday. Around 73N, 150W:

Is it wrong that I'm thinking a substantial portion of the Beaufort is going to be melted out by the 31st of May if these kind of temperatures are maintained?

be cause

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Re: The 2015 melting season
« Reply #930 on: May 23, 2015, 10:12:19 PM »
Hi Siffy .. based on last years summer forecasts I would not trust the GFS 2m temps forecast for the Arctic . Last year GFS spent the entire summer forecasting @ 10'c more than GEM for the Arctic as a whole . Seems to be the same again... 10 days out GFS has a frost free Arctic , Gem has it averaging @ -8'C . Last year GEM was by far the more accurate and looks likely again in 2015 . Still I don't doubt this is going to be a very interesting melt season :)
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

ChrisReynolds

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Re: The 2015 melting season
« Reply #931 on: May 23, 2015, 10:43:17 PM »
As of day 141 (21 May)...

6 years have 21 May extent below 0.5M km^2. Of these 1982, 1998, 2008, 2012 correspond to the following September having extent that is a local minima (i.e. a drop down from the years around those years). Only 1991 saw a September extent that was a local maximum.

Examining what happened in 1991 vs those other years is left as an exercise to the reader. ;)
i.e. I can't be bothered.  :P

Mt Pinatubo: The volcano's Plinian / Ultra-Plinian eruption on 15 June 1991 produced the second largest terrestrial eruption of the 20th century after the 1912 eruption of Novarupta in the Alaska Peninsula.
Might just  be relevant there.

Of course! I forgot all about that. There was a very interesting paper from years back about it - IIRC it was using Pinatubo to examine water vapour feedback in a model.

Lord M Vader

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Re: The 2015 melting season
« Reply #932 on: May 23, 2015, 11:06:20 PM »
I don't think we'll set a new record minima this year. It'll require perfect melt conditions including a strong cyclone arriving at the right moment later this summer. However, I do believe that there is a good chance that 2015 can be at 2-3 place by September if current conditions keep rolling.

If these conditions had been present in 2013 i wouldn't have had any doubts that 2012 years record minima could have been destroyed...

///LMV

jdallen

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Re: The 2015 melting season
« Reply #933 on: May 23, 2015, 11:21:36 PM »
Hi Siffy .. based on last years summer forecasts I would not trust the GFS 2m temps forecast for the Arctic . Last year GFS spent the entire summer forecasting @ 10'c more than GEM for the Arctic as a whole . Seems to be the same again... 10 days out GFS has a frost free Arctic , Gem has it averaging @ -8'C . Last year GEM was by far the more accurate and looks likely again in 2015 . Still I don't doubt this is going to be a very interesting melt season :)
be cause - can you point us at some sites producing summary maps based on GEM modelling output?

I'm sifting through a number right now that appear to use it, but if you have something specific, that would be useful.

(Edit:  I found this:
http://weather.gc.ca/data/model_forecast/colour_images/00_054_G1_north@america@zoomout_I_4PAN_CLASSIC@012_000.jpg
You have better?)
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ChrisReynolds

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Re: The 2015 melting season
« Reply #934 on: May 23, 2015, 11:24:20 PM »
Near Barrow (Thanks for the link Sonia)...

If HYCOM is correct then the ice edge in the Beaufort Sea looks like it's about to hit the multi-year ice, a stall might be expected over the next week to two weeks. But there's a lot of open water there before the solstice and warming water this early in the season might be enough to seriously attack the multi year ice. I hope so, that would open up the possibility of a good low extent by September.

It looks as if open water is trying to surround that MYI. Could it possibly be attacked on all sides?

The weather is interesting there, there is a band of cloud over that region.
http://weather.gc.ca/data/satellite/hrpt_dfo_ir_100.jpg

However Bremen shows not just reduced concentration persisting there, but also the structure of parallel fractures in the ice from the recent opening away from Banks Island - that's very big stuff! I'm certainly not saying a stall = loads of ice in September. And yes, that broken stuff behind the ice edge looks very promising.

Compactness is area divided by extent, using Wipneus's area and extent data*: I take the last ten days, 12 to 21 May (21 May is latest I have downloaded), and sort in order of lowest compactness.

2015   0.79
1998   0.81
1995   0.82
1991   0.84
2008   0.84
2012   0.85
1993   0.86
2014   0.89
1997   0.90
2011   0.90

2015 is the lowest on record and is 2.4 standard deviations below average compactness for 12 to 21 May.

The way that Beaufort is shaping up, reminds me of Laptev this time last year. it looks very promising for an exciting race in Beaufort. Now we just need Siberia to join in. But I am allowing myself to get a bit excited over Beaufort.

*PS, Wipneus's data is here.
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data
For full daily regional area and extent people need: nsidc_nt_nrt_detail.txt (recent data) and nsidc_nt_final_anom.txt.gz (finalised long term data).

I know that there is a lot of data there, but I keep getting the feeling very few are using this data and it really pays to put the time in to spreadsheet or write code to handle it.

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Re: The 2015 melting season
« Reply #935 on: May 23, 2015, 11:53:56 PM »
Just to tie up some details about Beaufort before I trash the spreadsheet...

Extent lowest 10.

1991   0.5033
1995   0.5076
2015   0.5077
2012   0.5086
2008   0.5106
1998   0.5148
1982   0.5209
2005   0.5229
1993   0.5263
2010   0.5268


Area Lowest 10

2015   0.403
1995   0.415
1998   0.415
1991   0.420
2008   0.429
2012   0.435
1993   0.454
2014   0.469
1997   0.472
2005   0.474


So beaufort is the third lowest extent, the lowest area, and the lowest compactness for 21 to 21 May since 1979.

That means there is less ice, and what ice there is is more spread out.  ;D

jdallen

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Re: The 2015 melting season
« Reply #936 on: May 24, 2015, 12:00:42 AM »
... Last year GEM was by far the more accurate and looks likely again in 2015 . Still I don't doubt this is going to be a very interesting melt season :)
On a hunch I started looking at historical data regarding precipitable water.  If you look at 2013 and 2014 for this period and compare it to the present, the difference is pretty clear - there is a lot more moisture continuously flowing into the Arctic as compared to those two years.  Not sure how to quantify it from the images, but by eyeball - 25 to 30% seems minimum.

Edit:  I also think it may be useful to point out that the areas on the same date in 2013 and 2014 with highest moisture available roughly correspond to the areas of greatest melt activity later in the season.  By extrapolation from that, it may follow that we will see greater melt activity over a broader area in 2015, based on the greater extent of available moisture in the atmosphere over those areas.

(I am aware I'm comparing GFS with CFSV2 - but I think the general qualitative comparison is still useful...)
« Last Edit: May 24, 2015, 12:07:02 AM by jdallen »
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be cause

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Re: The 2015 melting season
« Reply #937 on: May 24, 2015, 12:30:32 AM »
sorry JD .. my observations were based only on regularly comparing the forecasts on Metrociel . It was obvious last summer that the 'toasting' and 'torching' so often promised was just not materializing . Just as now they were never promised on GEM but always on GFS .
 I am a very rudimentary user of the internet and have no computer training so can offer little in way of direction . I do however thank all you regular contributors here for bringing me a world of knowledge and information every time I come here .. the only site Bing tells me I am 'very active' on .
Thanks everyone ! :)
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Jim Hunt

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Re: The 2015 melting season
« Reply #938 on: May 24, 2015, 01:47:50 AM »
Can you point us at some sites producing summary maps based on GEM modelling output?

Meteociel covers most bases:

http://www.meteociel.fr/modeles/geme_cartes.php?ech=6&code=0&carte=1&mode=9&archive=0
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Re: The 2015 melting season
« Reply #939 on: May 24, 2015, 02:30:52 AM »
OMG!!! 06Z GFS has the entire CAB above freezing on the 29th and 30th!!!  :o

I predict the unprecedented - that by June 5th, the central Arctic will have discernible surface melt on MODIS...

That is preposterous, there is absolutely no possible way that the CAB could reach those temperatures this early in the season.  Obviously the GFS is overstating the temperatures.  It isn't even June yet!

I wouldn't trust that model run output.
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« Last Edit: May 24, 2015, 02:46:51 AM by jai mitchell »
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Re: The 2015 melting season
« Reply #941 on: May 24, 2015, 02:52:17 AM »
OMG!!! 06Z GFS has the entire CAB above freezing on the 29th and 30th!!!  :o

I predict the unprecedented - that by June 5th, the central Arctic will have discernible surface melt on MODIS...

That is preposterous, there is absolutely no possible way that the CAB could reach those temperatures this early in the season.  Obviously the GFS is overstating the temperatures.  It isn't even June yet!

I wouldn't trust that model run output.

Actually, per DMI N80 graphs, 2012  saw temperatures reach 0C about June 1st, briefly dip below, then rise above 0C for the rest of the summer.  So I wouldn't call it preposterous - though probably unlikely.  Large increases this time of year in the N80 temps are not unheard of - 2002 and 2012 both showing large jumps in late May. 


jdallen

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Re: The 2015 melting season
« Reply #942 on: May 24, 2015, 06:24:04 AM »
OMG!!! 06Z GFS has the entire CAB above freezing on the 29th and 30th!!!  :o

I predict the unprecedented - that by June 5th, the central Arctic will have discernible surface melt on MODIS...

That is preposterous, there is absolutely no possible way that the CAB could reach those temperatures this early in the season.  Obviously the GFS is overstating the temperatures.  It isn't even June yet!

I wouldn't trust that model run output.

Without sounding too wry... it's no more preposterous than 25C temperatures along the coast of the Beaufort Sea by the third week in May.  There are a lot of things out of whack right now.  That doesn't prove the model is going be right, but neither do current conditions preclude it being wrong.

Edit:  Jai - you might want to look at the moisture influx into the Arctic via the Bering and Alaska.  The steady stream of cyclones is moving huge quantities of moisture - easily twice as much as is typical - into the CAB.  Compare what exists now, is being forecast, and what was present the last few years.  That increase in available atmospheric H2O is my sense of why we are and will see abnormally high temperatures.

The clouds and moisture are not the same phenomena we saw last year later - when evaporation from open leads produced low lying fog and cloud cover.  My sense is this is import of huge amounts of moisture into the arctic, by way of the tropical storms we've watched all winter in the east pacific.  This is something very different from what we've seen previously, especially in its persistence.

As long as the pattern spawning those cyclones persist, and the blocking high off/near the North American NW coast persists, those storms will hit that blocking high, break up, and their remnants will be shoved into the basin as if on a conveyor.  That's what's been happening the last 2-3 weeks, and shows no sign of slowing down.
« Last Edit: May 24, 2015, 07:44:58 AM by jdallen »
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Re: The 2015 melting season
« Reply #943 on: May 24, 2015, 07:22:28 AM »
You do not step in the same river twice.

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Re: The 2015 melting season
« Reply #944 on: May 24, 2015, 07:43:33 AM »
The 00z GFS is insane.

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Jim Hunt

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Re: The 2015 melting season
« Reply #945 on: May 24, 2015, 12:00:44 PM »
I'm not sure how reliable these numbers are, since everything has suddenly burst back into life after a week's gap with the Mackenzie River flow already declining. There's an Aqua image of the delta area to go with it:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort
« Last Edit: May 24, 2015, 01:19:42 PM by Jim Hunt »
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Re: The 2015 melting season
« Reply #946 on: May 24, 2015, 01:10:50 PM »
comparison to 2012 here:  http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=05&fd=20&fy=2012&sm=05&sd=20&sy=2015



The snow cover on the 2015 image is suspect, I'm pretty sure Alaska is basically snow free, save the mountains. Amongst other areas.
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JayW

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Re: The 2015 melting season
« Reply #947 on: May 24, 2015, 01:20:48 PM »
In my very humble opinion, the NAEFS are one of the best tools for 2m temps.  It's a combination of the NCEP ensembles (GEFS) and the Canadian GGEM ensembles (GEPS), and I use the NCEP output.  It's certainly not the prettiest,, and perhaps rough with 5°C isotherms, but it's relatively reliable, and since it's a mean of about 50 forecasts, it tends not have its extreme moments. 

The contours are temperature, and the color shading is the spread.
http://mag.ncep.noaa.gov/Imageanis.php
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Re: The 2015 melting season
« Reply #948 on: May 24, 2015, 01:22:58 PM »
comparison to 2012 here:  http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=05&fd=20&fy=2012&sm=05&sd=20&sy=2015



The snow cover on the 2015 image is suspect, I'm pretty sure Alaska is basically snow free, save the mountains. Amongst other areas.

What ever algorithm that spat out the image for 2015 on that date is drunk.



Here's a sat view of Alaska on the 20th of may. The snow cover for the northern hemisphere is ridiculously oversized in that image.

Jim Hunt

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Re: The 2015 melting season
« Reply #949 on: May 24, 2015, 01:25:58 PM »
I'm pretty sure Alaska is basically snow free, save the mountains. Amongst other areas.

Quite so. An alternative point of view:

http://www.nohrsc.noaa.gov/nh_snowcover/
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