Area graphs: 3 million km2 mark passed

We are getting closer to the minimum sea ice area, which comes a bit earlier towards the end of the melting season than sea ice extent because of the simple fact that low air temps start to make melt ponds and even water between ice floes freeze over. This effect shows up immediately in sea ice area data, but a bit later in sea ice extent data, due to the different ways they are calculated.

The Cryosphere Today minimum SIA was recorded quite early in 2005 (August 31st) and quite late in 2006 (September 16th), but in the last few years minimum sea ice area occurred between September 7th and 9th. Even though we still have about two weeks to go, it's interesting to have a preliminary look today at what the different sea ice area graphs are showing us.

The main reason is that the Cryosphere Today SIA has passed the 3 million square km for the second time in recorded history, the other time this happened, was in 2007 (graph courtesy of Piotr Djaków):

The 3 million mark has been passed 10 days earlier than 2007 and only a drop of about 68K square km is needed to break the minimum SIA record, but it might take the full two weeks to happen. Area can now go up and down very arbitrarily, depending on weather conditions. If things turn really bad up there, we might even see an early minimum SIA like in 2005, with no record broken. But chances of this happening are slim.

Larry Hamilton's bar chart gives an excellent impression of how this year stacks up so far, compared to minima in other years:

There are some other SIA graphs that are updated on a daily basis, such as the one by Arctic ROOS which uses SSM/I data provided by NERSC:

Although not as low as on the Cryosphere Today SIA graph, the 2011 trend line is also getting very close to 2007, after seemingly having beaten the 2008 minimum SIA already. We see the same thing on this SIA graph by IARC-JAXA (also known as IJIS), the research center that produces the well-known SIE graph and bases its data on the AMSR-E sensor aboard the Aqua satellite:

There are some differences in the details of course, which is to be expected as different sensors and algorithms are used to record and process the data, but all sea ice area graphs seem to agree that 2011 has passed the 2008 minimum SIA and is very close to the 2007 record. In two weeks we'll know more, if not everything. Extent will soon follow.

Comments

[Kevin McKinney]

Thanks, Neven. It looks as if SIE will hew somewhat close to this general pattern as well--IJIS is poised to break through the 5M milestone, which would be the second-earliest also. There's a bit more separation between 2011 and 2007 SIE, of course.

But I'm sure you'll have lots more to say about that!

As usual, we must wait to see what happens. That uncertainty is a big part of the intrigue of watching the ice, I think!

[Lord Soth]

The way SIA bounces around, I would consider 68K noise. But it still be nice to beat 2007 SIA on paper, despite the large error bars.

[Wayne Kernochan]

I would also note Neven's (?) recent remark that the big dip in area seems to lag that in extent by 2-3 days. If so, then, all else being equal, that 68K may already be baked in, since extent has dropped by 70K over the last 2-3 days ... - w

[Andrew Xnn]

Looks like the most significant contributor to the record is the central Arctic Basin. It is almost half of the roughly -2 MKm2 anomaly.

Some of the other basins melted out earlier than normal and their anomalies have been rising and have been trending closer towards zero and thus contributing less to delta over the last 2 weeks.

Clearly, since 2007 Arctic sea has entered a new era.

[Rlkittiwake]

I'm just marinating in the knowledge that a massive hurricane is set to hit the east coast, O'sellout gave his thumbs up to the oil sands pipeline, and sea ice is hitting the all-time epic low all on the same weekend.

Irony's not dead, folks.

[L. Hamilton]

Just back from a brief vacation, I updated the year-to-date area graph. Will be following that and the other indexes closely over the next few days.
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_N_min_to_date.png

[Werther]

Completely off topic...
Actually at the moment I’m captured watching the arrival of Irene, Morehead City, NC. CrazyMother TV has a live video stream. I located it on Google Earth. The reporter is on a boatlaunch on the Intra Coastal Waterway, some 3 km from the Atlantic shore. There is a surge, coming 30 meter into the shore (of the ICW), some 2-3 meter over normal sea level.
Unbelievable what info you can access through the internet!
The only link I guess could be on topic, is that these cyclones may pull a lot of heat out of the tropical seas, transporting them up north.
Remember Igor, ending up near the SW Greenland coast september last year?

[Seke Rob]

Did a bit of chart borrowing of L.Hamilton and reproduced his minimum CT SIA and slapped the dates of the minima reached on top, to see if there was any pattern [See Chart]. None, but it is interesting how metronomic the minimum has sat to happen around day 251 for the last 4 previous years, suggesting [very softly] we could have +/- 8 days of reduction by that indicator.

There's also a Maximum CT SIA Chart with the days when those were reached on top. Not seen anything to conclude of that.

[L. Hamilton]

Seke Rob, in connection with the Modern Area of Ice post, I looked for shifts in the date of CT North minimum -- that would be interesting. I didn't see anything, though. It seemed that turnaround dates could be regarded as a function of weather.

The range of area minimum dates is Aug 31 - Sep 30, median Sep 8.5.

[L. Hamilton]

Nice enhancement to the graphic, though!

[r w Langford]

Love your graphs guys. Being an artist of sorts the visual pathways work great for me.

[Neven]

Thanks, Larry. I'm adding your updated graph to the post.

[Seke Rob]

Nice you like the pimp. There's a little mislead [to me] in the chart. Day 243 is August 31, so melt could indeed go on a little longer :D

CT, just out, only marginal change from 24th > 25th. The Antarctic data is 1 day behind, so global is only known through the 24th, but it downed 150K, turning the anomaly to -2.16 million km^2. The red line (2011) [See Chart], dove against the rising blue (2007). Now to watch if red is going to cross directly to that 2010 low point, below which 2011 has now moved twice.

[Seke Rob]

Since there are now 2 years that have a below 3 million square kilometer area 'moment' [euphemistically to certain quarters], expanded the first day area < 9 to 4 million day graph [See Chart] and added 3M, for 2 fat red datapoints. In 2007 it happened 1 day earlier than in 2011 and passing the 3M line then by a mere 2,136 KmSq.

[Seke Rob]

Whilst the Arctic skipped up 98KKmSq, the hearts of the lukers was not set to move out of their depression

2011.6466 -2.1628795 17.5675526 19.7304325
2011.6493 -2.3452401 17.3571892 19.7024288

That's a leap towards the global anomaly record at -210K going from the 25th to the 26th [See Chart]. Those anomalies are funny beasts... un-smoothed, there can be shifts of 400-500K in a few days.

At any rate, looks like a new low for the 2011 boreal summer.

[Phil263]

SIA shot up another 40 k, it is now at 3.122 million, more than 140 k above the recent minimum of 2.98 million. Have we already passed the minimum for this year? I looked at previous years and I haven't seen anything like that at this time of year!

[Neven]

Phil, I'd be mightily surprised if minimum SIA had been reached so early. On the other hand, it will be difficult to go below this year's minimum so far. Or will it? Last year there was a drop of almost 143K around this date, and 2005 had one of 138K on the 30th.

Either way, I don't have to change the title of this post. It looks like the 3 million square km mark is passed more than once. In both directions. ;-)

[Neven]

Meanwhile, SIA in Antarctica is falling off a cliff. If the Arctic SIA keeps steady for a while, or makes a big drop, the current record global SIA anomaly will be history.

[Lord Soth]

The rise in the sea ice area is due solely or mostly due to a spike in area increase in the central arctic basin (notice the much larger scale for the central arctic basin)

I'm not sure what percentage is due to sensor noize, and what is due to melt ponds freezing over, but this year has has a lot of variability.

These sharp spikes up, can be quickly erased by sharp spikes down.

Regardless, SIA is going down everyday and probably will for the next two weeks, and we may achieve a first place finish on paper during the next wave of downward spikes.

Regardless, 2007 and 2011 is most likely within the error bars, so statistically, we probably already have a tie.

[L. Hamilton]

Regarding the *global* sea ice area, as Neven mentions we're only 20k above the record there as well. But there's no telling which direction it's headed.

http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_CTglobal_min_to_date.png

[Neven]

Just 20K? That's interesting. I was only looking at anomaly and never thought about looking at the total. Thanks, Larry.

[L. Hamilton]

Global sea ice variations show an interesting pattern -- dominated within years by the larger Antarctic seasonal variance, but across years by the stronger Arctic trend. I've got a nice graph of this somewhere, perhaps worth posting after the Arctic melt season cools off.

[Wayne Kernochan]

A couple of more random thoughts about global area: If today's Arctic and Antarctic areas simply stay where they are today, then about 18 days from today we would be on the edge of a new negative anomaly record. And if we get a late freeze in the Arctic, we have an excellent shot at a new maximum yearly value record.

Remember, last year the deniers were out in force at about this time pointing to a close to record Antarctic extent maximum, coupled with a higher than usual Antarctic area. It certainly doesn't appear likely that that will happen this year.

[L. Hamilton]

Correction to my earlier note, the global sea ice area was only 20k above the one-day record earlier this year, on January 24. It's currently several million km^2 higher than that. Global minimum area occurs during the austral summer, when most of the Antarctic sea ice is gone.

[Seke Rob]

Wayne Kernochan | August 29, 2011 at 18:26

Well, and then came that late dip in 2011 for Global SIA that they did not count on ;>)

CT updates...
Arctic
2011.6548 -1.8083068 3.1219401 4.9302468
2011.6576 -1.8158386 3.0820990 4.8979373

Antarctic:

2011.6521 -0.4948436 14.2354136 14.7302570
2011.6548 -0.4780137 14.2829218 14.7609358

Global:

2011.6521 -2.3883979 17.3165398 19.7049370
2011.6548 -2.2863250 17.4048615 19.6911869