Barrow Break-up 3

This blog post was preceded by Barrow Break-up 1 and Barrow Break-up 2 (both containing more general info).

The Sea Ice Group of the Geophysical Institute at the University of Alaska Fairbanks has been issuing break-up forecasts for almost three weeks now. Their current forecast is for the grounded ridges approximately 5 miles off the coast of Barrow to give way on July 9th. They have been making precise forecasts since a couple of days, as break-up can be forecast no more than 16 days in advance.

Their forecast is based on the mean shortwave flux, or in other words how much energy from the sun reaches the surfaces (in W/m2). Confused and silly as I am, I had called this 'solar flux', which I believe is something else entirely.

Here is their graph:

Lots of insolation when the forecast was first made, but since then Barrow seems to have clouded over. Nevertheless, we have seen the sea ice between the ice ridges and the coast continue to melt on the Barrow webcam.

I have again retrieved images from this archive (2006 and 2007 are still images from these time-lapse videos) to compare them with this year's image on June 22nd (click for a larger vision):

Where I didn't see a lot of major differences between years on the previous comparison, there are a few visible now. The coast had almost cleared by now in 2007 (june 27th) because no grounded pressure ridges had formed during winter. On the image from 2010 (lower left corner) you can clearly see the grounded ridges in the distance.

When it comes to open water, right now this year resembles 2009 most. More open water means that more solar energy is absorbed and warmer water erodes grounded pressure ridges from below. In this sense 2011 seems to be ahead of 2010, but the latter was much less cloudy and thus had more solar energy coming in.

And these images are of what's happening in front of Barrow, not what is happening in front of the Navy Arctic Research Laboratory (NARL), approximately 5 miles north of Barrow. Which is the exact place where the break-up of the land-fast ice and its grounded ridges is forecast to happen.

 

So all in all the break-up forecast from the Sea Ice Group of the Geophysical Institute at the University of Alaska Fairbanks looks very solid. I'll come back to this when the break-up has occured. For now I leave you with this comparison between 2009, 2010 and 2011. The image from 2009 is a week later, clouds were blocking the view on all other dates:

Comments

[michael sweet]

The web cam at Barrow has been off for the past few days. Todays Modis image clearly shows a lot of shore fast ice breaking off near Barrow. I cannot tell if it broke off in front of the Naval Research station, but it is definitely nearby. That suggests that the ice will break up well before the forecast this year.

[Neven]

The forecast is now for July 11th (just like 2009).

Michael, I think the fast ice is breaking off tot he North of Barrow and NARL. There is an animation and an image in Barrow Break-Up 1 that shows you exactly where Barrow and NARL are.

[michael sweet]

Neven,
I actually think the fast ice break off is just to the south of Barrow. NARL is almost at the top of North America, there is only ocean north of there.

someone linked a google Modis image. Can that be reposted (or just say what thread it is in), I forgot to bookmark it.

[Neven]

I see what you mean now, Michael. I had to scroll a bit to the right on the 250m-resolution image.

This fast ice breaking up is not where Barrow is. Barrow is in the next frozen bay that is still intact.

[Neven]

WRT the Barrow Webcamera:

Please note: we have been experiencing network problems with the camera recently. As a result the picture below may be several days old. We are working on the problem and hope to have it fixed as soon as possible.

[Christoffer Ladstein]

As long as it's just the network, we'll at least have a fair chance to watch the "movie" of 2011 later...

[Werther]

Break up in front of Barrow is imminent now:
Arctic_r05c03.2011179.terra.250m
Lots of action around the Chukchi Sea; break up on Pevek Bay,too. Wrangel Island almost 10 degrees maximum. Large polynia over there is connecting with the open sea.

[Artful Dodger]

Diapycnal: (definition)

In the ocean, density always increases with increasing depth. However, surfaces of constant density (called "isopycnals") are not always level. Wind, the rotation of the Earth, and other processes cause density surface to slope.

The direction at right angles to the local isopycnal surface is called the "diapycnal" (i.e., across-isopycnal) direction. The angle between the diapycnal direction and vertical (i.e., directly out from the Earth) is always very small, a fraction of a degree at most.

However, the difference between the two is important because the slope of isopycnals tells us a great deal about how the ocean is moving, and how it can interact with the coast and the atmosphere.

Courtesy: ESR glossary

[Neven]

The break-up forecast has gone back to July 8th, and some more on the recent breaking up of much of the fast ice in the 'bay':

Much of the landfast ice broke off at once between downtown Barrow and Point Franklin (100 km, 60 mi SW of Barrow). Barrow resident Jason Herreman, Department of Wildlife Management of the North Slope Borough: "Between 2 and 5 [pm] today the pack ice and shorefast ice from Barrow playground/bank building and everything South started heading north at about 2 knots. The only ice not moving in that area are some large grounded pressure ridges. The shorefast ice north of Barrow proper does not appear to be moving at present." While this event is highly significant for the Barrow community, this is not the break-up we are looking for on this page.

A storm surge may have arrived in Barrow on the 27th, helping to dislodge landfast ice.

[Artful Dodger]

Barrow Webcam -- June 28 2011:

[Neven]

Forecasted break-up date has shifted a day back, to July 7th.

[Neven]

One thing I don't get is that the break-up is forecasted on July 7th, but the accompanying graph with the mean shortwave flux is showing something like July 14th.

[Peter Ellis]

Um, no? The dark red dots are simply a 16-day extended weather forecast starting from today.

What matters for the breakup forecast is when the weather projection enters the shaded region at the top of the graph. Counting the dots, that happens on the 3rd dot after it crosses the "4th July" dotted line. That is, the likely date of breakup is the 7th.

[Neven]

Thanks, Peter. I get it now.

[michael sweet]

The ice at Kimmirut (one of the web cams on the Arctic Ice page) broke up today. Does anyone know when the ice usually breaks up there?

[Artful Dodger]

Hi, Michael. This page says breakup is usually mid- to late-June.

[WhiteBeard]

Here are 4 shots of the ice off Barrow on May 27th. They are from a photo feature that went up on the 30th at the Anchorage Daily News web site.

http://www.adn.com/2011/06/29/1943090/a-summer-day-in-barrow-alaska.html#id=1943147&view=large_view

http://www.adn.com/2011/06/29/1943090/a-summer-day-in-barrow-alaska.html#id=1943142&view=large_view

http://www.adn.com/2011/06/29/1943090/a-summer-day-in-barrow-alaska.html#id=1943087&view=large_view

http://www.adn.com/2011/06/29/1943090/a-summer-day-in-barrow-alaska.html#id=1943089&view=large_view

[Neven]

Thanks a lot, Whitebeard! Some images are very illustrative.

The forecast has moved forward to July 12th again, perhaps having to do with that big low that is forming over the North American part of the Arctic.

[Neven]

The forecast moved to July 9th and then to July 10th.

I don't know. If the current ECMWF forecasts come about, there will be some high-pressure areas that should take that ice apart from all sides.

I think things will break up around July 5th or 6th.

[Paolo]

Hi all,
Break-up ?!!

[Neven]

Thanks a lot for bringing this to our attention, Paolo!

Let's see whether the forecast changes today or if a break-up is reported. Unfortunately satellite images are too cloudy to see what is going on down there.

[Peter Ellis]

Paolo, that's the webcam in Barrow town. The ice broke up there on the 28th, as already discussed in the comments above. Point Barrow is north of that, and there's no direct webcam data from it.

[Neven]

What happened on the 28th was south of the webcam I believe. There's also a marked difference between today's image and one from the 28th (as posted by Lodger).

BTW, I'm not saying there has been a break-up. It's just too bad there aren't any clear satellite images. I think some of the landfast ice is still there...

[Artful Dodger]

Peter is correct. The "observations" section of Barrow Sea Ice Break-Up shows fast-ice is still present off of the Navy Arctic Research Lab (NARL). Here is how the Researchers call Breakup:

What is Break-Up

We define break-up as the first detected movement of landfast ice shoreward of grounded ridges within the 20 m-isobath off NARL, approximately 5 miles north of Barrow. Typically, movement is parallel to the coast, confined by grounded pressure ridges at the 20 m-isobath. However, we exclude ice affected by dust from town and a coastal road, i.e. the first approx. 100 m off shore. Typically, we detect movement from coastal RADAR and from Satellite imagery. In previous years, webcam images near NARL were available

[Artful Dodger]

Well, not sure what happened to the URL...

Try the Observations 2011 section here:

http://seaice.alaska.edu/gi/observatories/barrow_breakup

The most recent satellite image is on the right...

Cheers!

[paoloc]

Hi,
Above all sorry for my webcam real time picture (and not archived picture) and damned morning fog..
Now the fog is out and the extern strip of the fast ice seems vanished (it is only a webcam picture and this is not absolutely clear)
Peter, I know that the webcam is in Barrow town and for this I used a question form “?!” (and also because the quality of information : webcam picture)
To end, I don’t think we must wait the 10 July for the break-up, wait and see
Very good blog and sorry for my English

[Neven]

This just in from the sea ice group:

3 July 2011: Break-out of ice right at downtown Barrow, and of ice seaward of pressure ridges between Barrow and Point Barrow.

Very, very close.