Sea ice extent update 5: 10 million, here we come

I'll be regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2006-2009. The JAXA graph is favoured by almost everyone, probably because it looks so nice compared to other graphs (like the one by Arctic ROOS, the University of Bremen and the Danish Meteorological Institute). All the years have a nice colour of their own which makes it easy to eyeball the differences between trends. Most of the betting on minimum SIE is based on the IJIS data. NSIDC has a nice explanation of what sea ice extent is in their FAQ.

June 18th 2010

Yesterday I was expecting to write that 2010 was slowly returning to the pack and join the other years before the unofficial start of the season (on the 21st of June, the day of the year with the longest hours of daylight in the northern hemisphere), as it had come in 4th the day before yesterday, and 2nd the day after that. But 2010 seems to have decided it wants to remain an Einzelgänger a little while longer and had the highest reported melt of today's date: 77,812 square km.

With just 23K to go it looks like the 10 million square km threshold will be officially crossed tomorrow, 4 days ahead of 2006 and a whole week ahead of 2007.

The current difference between 2010 and the other years is as follows:

• 2006: -262K (59,609)

• 2007: -500K (63,328)

• 2008: -590K (56,474)

• 2009: -649K (55,938)

Between brackets is the average daily melt for June. These averages get a bit higher towards the end of the month in anticipation of the heavy melting of July and August. With a current average daily melt of 62,555 square km 2010 has a good chance of beating the other years, but it will need 1 or 2 century breaks to do so.

On NOAA's daily AO index we can see that the Arctic Oscillation is still in a positive phase:

TIPS - Other interesting blog posts concerning Arctic ice:

Patrick Lockerby has published the second instalment of his MODIS satellite image tutorial called 'Rapidfire for Citizen Scientists'.

Wayne Davidson has a short update out. Quote:

Big Blue is expanding everywhere in the high Arctic, leads along the Arctic Archipelago coast are clearly seen for the first time since early spring. This will accelerate the melting tremendously, since its occurring at the solstice, very high sun, and will further demolish previous ice extent records. Everything is coming about as expected.... Unfortunately....

Comments

[Lord Soth]

June 21st is the solstice, however the seasons are delayed. Here around 45 degrees north, the climatic maximun occurs around August 1. From the short history of the arctic records, it appears that the climatic maximun occurs sooner around the middle of July, but this could be due to the shortness of the records.

I have looked for a chart of the date of climatic maximun temperture vs latitude but have never found one. Also, maritime vs continental climate would probably dictate two graphs.

So we have another 5 weeks of turning up the heat on the arctic, before we even talk about the descent into fall, and that sun will be beating down on increasing open blue water.

[Patrick Lockerby]

Lord Soth: If you take the dates per latitude of first exposure to 24hr sunshine and add number of days / 4 you get a ballpark figure for delayed maximum temperatures.

It's a ballpark figure, but it gives you something to work with.

This list may be useful:
http://www.scientificblogging.com/chatter_box/blog/lands_midnight_sun

[Patrick Lockerby]

That should read: add number of days / 4 to solstice date.

[Neven]

2010 crossed that 10 million threshold quite hard with a reported melt of 97,188 square km and is now at 9.925 million square km. We'll have to wait for the revision later today to see how much of the melt number gets chopped off, but I doubt 2010 will take a step back across that threshold.

[Anu]

Looks like they nailed down 06/18/2010 at 9,933,594 sq.km.

6/19/2010 is so far at 9,813,281 sq. km, for a quite impressive 120,313 sq. km. melt.

Do you remember what the "revision" explanation is ? I think I read IARC_JAXA applies a smoothing filter, but I don't have time to look it up right now...

There's still an OK chance of setting a new record minimum this summer - but I also thought there was a good chance the Boston Celtics would win the NBA Finals this year, up until the second half of the fourth quarter of Game 7. It's hard to make predictions, especially about the future.

Look at the Northern Hemisphere Land-Ocean temperature anomalies for Jan -> May:
http://data.giss.nasa.gov/gistemp/tabledata/NH.Ts+dSST.txt
Warmest three months ever coming into the summer melt season.
I think the two biggest annual influences on summer melt are the ocean temperatures (of the water getting into the Arctic Ocean - mainly from the Atlantic, much less from the Pacific) and pre-conditioning of the ice (thinning).

If the Professors working on PIOMAS are more insightful than Steve Goddard at WUWT, then there's a good chance the sea ice is pre-conditioned for a sobering melt:
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolumeAnomalyCurrent.png
July 1 will be an important milestone - if still below 2007, then we might have the newest minimum since 2002, 2005 and then 2007.

[GFW]

Anu, surface transport of ice out the Fram Strait is fairly high on the importance list too. While I'll definitely take PIOMAS over Goddard, that recent story about the aerial survey finding "lots" of 4m ice would suggest there's a bit more ice than PIOMAS thinks ... assuming that the aerial survey's sensor was well calibrated, and that "lots" means what it usually means.

The 120,000 (preliminary) drop today is impressive. Even revised, it will likely be another of Neven's "century breaks". As of today, it really looks like 2010 "wants" to parallel 2007 on the IJIS graph. We'll just have to see.

[Neven]

GFW, that survey was done last year. Some news paper reporter has written a story about it nevertheless, offering WUWT the opportunity to regurgitate it happily.

You can read the paper here.

You can have a look at data and maps here.

[Neven]

BTW, Environment Canada has released a new 30 day forecast a few days ago.

An excerpt:

As a result of above-zero mean temperatures over the
southern part of the Central Arctic, ice will melt at an increasing rate
during the first half of July and extensive melt ponds will develop.

[Lord Soth]

Anu, The smoothing alg. is only applied between May 20 to June 11, to smooth out a blip that have been occuring around June 1, due to the recalibration fo sensors, as the high arctic goes from the ice being dry to the ice being wet (wet snow, melt ponds, etc).

The revised figures could be due to a lot of things. My theory is that they have additional sat. passes to go on, and areas with heavy cloud cover may be clear in the next pass, and they can revised the figures for those areas with better accuracy. In the summer, I have seen the figures be revised further downwards, instead of upwards.

Well not about arctic ice, the following arcticle is quite interesting.

http://climatechangepsychology.blogspot.com/2010/06/oil-drum-unattributed-doomsday-scenario.html

Apparently, the BP well in the Gulf, could be compromised down shaft, with terrible consequences for the enviornment. It may be a bit alarmist, but what bothers me, is that everything the explain is possible, and is mirroring reality.

[Patrick Lockerby]

Currently there's a lot of leads, cracks, meltwater ponds and holes all over the Arctic. Consolidated ice can only melt from the top down if the sea temperature remains at or below freezing.

If meltwater gets through the ice, it floats on the more saline ocean, raises the local under-ice SST - invisible to satellites - and, in my opinion, has the potential to substantially increase the melt rate. Water contact melts ice faster than solar radiation.

[Anu]

Posted by: Lord Soth | June 20, 2010 at 13:17
Yes, there is that smoothing too (I think they change the algorithm to better handle melt ponds in the Spring).

But part of that "revision" every day is also a running average of values - NSIDC uses a 5 day running average (weighted differently for each of the 5 days), and IARC-JAXA uses a two day running average:
(If you watch the NSIDC daily graph, you can see the leading tip flop around as they apply the running average smoothing)
http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
Averaging period and the update timing of daily data

In general, sea-ice extent is defined as a temporal average of several days (e.g., five days) in order to eliminate calculation errors due to a lack of data (e.g., for traditional microwave sensors such as SMMR and SSM/I). However, we adopt the average of two days to achieve rapid data release. The wider spatial coverage of AMSR-E enables reducing the data-production period.

Usually the latest value of daily sea-ice extent is fixed and updated at around 1 p.m. (4 a.m.) JST (UT). Before the value is fixed, we also assign a preliminary value of daily sea-ice extent several times (usually three to four times) as an early report, which is determined without the full two-day observation coverage. (The fixed values of sea-ice extent are determined with the full coverage of observation data.)

JAXA has articles on its research, e.g.:
http://www.eorc.jaxa.jp/en/imgdata/topics/2008/tp080514.html
I read about their daily revisions of sea ice extent data there once, but can't find it this morning...

[GFW]

Neven, thanks for the link to that paper. I swear the "mainstream" news source I read completely left out the survey year. I gotta keep reminding myself just how bad most science reporting is. Someone I was reading recently (maybe Michael Tobis) had some interesting thoughts on that. It seems that in the past most science journalists came to journalism after doing something science-related. Now newspapers generally only hire j-school grads. Hence a diminished capability to report science.

Anyway, continuing my thought from my previous post, it seems the pre-conditioning for melt-out is the greatest on record, but the Fram export is stalled. So things could go either way. The Nares export looks like a conveyor belt though.

[Kevin McKinney]

Neven, thanks for bird-dogging down the Haas paper. I'd looked for it, but to no avail. It's interesting to be able to look at the work a little more closely. It really doesn't say anything that dramatic, though Dr. Haas does use the word "recovery," which pushes my buttons a bit, given that (as he himself observed in the press release) the declining trend is highly likely to continue over the coming years.

[Neven]

And as you can see on the pictures in the paper they just surveyed a few parts of the Arctic (where the multiyear ice is). I believe it has received some attention again, after having received plenty of attention last year, because their research has just been published in GRL or some such.

The ice probably has thickened here and there in the last two 'recovery' years, but it won't matter if this year's weather conditions resemble those of 2007. That much is clear. We'll know more in a few weeks.

Sorry for sounding like a broken record.

[David Gould]

Neven,

Are you able to give more information about the Fram Strait and how it's going this year as opposed to past years? Perhaps a few comparison pictures, for example, in a new post? Just something that I would be interested in. :)

David