During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily IJIS sea ice extent (SIE) and Cryosphere Today sea ice area (SIA) numbers, which I compare to data from the 2005-2011 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything that can be of particular interest.
Check out the Arctic Sea Ice Graphs website for
daily updated graphs, maps and live webcam images.
ATTENTION: There are still 3 days left to vote on the polls in the right hand bar.
One is for Cryosphere Today minimum daily sea ice area, the other for NSIDC minimum monthly sea ice extent (the one that is used for the SEARCH SIO projections). More info in this blog post.
July 28th 2012
I'm basically going to say the same thing as I did in the last ASI update: Weather patterns haven't been conducive to sea ice decrease, trend lines on graphs should be stalling, but they don't. As I've shown in yesterday's blog post comparing this year's weather patterns in June and July with previous record years, the decrease should have slowed down significantly like it did in 2010 and 2011, but it didn't. The 2012 SIE trend line shouldn't follow 2007 so closely, but it does. The 2012 SIA trend line shouldn't lead, but it does.
Now air and sea surface temperatures are higher than in previous years, but does that explain all of it? Personally, I don't think so. I think ice thickness is playing a big part in all of this. One of the conclusions I found most important last year, was that, yes, the weather is still dominant and determines whether a melting season will see a new minimum record or not, but only as much as ice thickness will allow it. There comes a point when large parts of the ice pack become so thin that it doesn't matter what the weather does. Sure, ideal conditions will cause a nosedive, but the train keeps chugging along, even when the weather isn't so great for melt, transport and compaction.
I believed I saw that in September 2011. I believe I'm seeing it now too,
4-6 weeks earlier. Maybe my eyes deceive me.
Sea Ice Extent (SIE)
In the last ASI update I was wondering whether the 2012 trend line
on the IJIS SIE graph would veer off to the right towards big staller 2010:
But it didn't. Especially in the last couple of days the 2012 trend line has decided to track new leader 2007, after following 2011, which had a brake put on its decline in mid-July. 2007 had a very strong first week in August, so it will be interesting to see whether 2012 can keep up or not.
The current difference between 2012 and other years (without the unrealistic last data point that gets revised upwards) is as follows:
- 2005: -593K (-83,709)
- 2006: -608K (-70,025)
- 2007: +198K (-98,608)
- 2008: -683K (-81,260)
- 2009: -371K (-92,127)
- 2010: -376K (-62,601)
- 2011: +90K (-83,473)
Between brackets is the average daily SIE decrease for the month of July. 2012's average daily SIE decrease for July currently is -87,101 km2 per day, which is quite a bit less than 10 days ago, but given the circumstances quite high. One would have expected it be more like 2010's average of -63K, but it's actually third highest.
Sea Ice Area (SIA)
Despite a couple of slow days in the past week, the situation on the Cryosphere Today SIA graph is basically the same:
Here we see the difference between area and extent at work. The slowdowns in 2010 and 2011 are less apparent here because of melt ponds and holes within the ice pack. This year there are a lot of holes on the Pacific side of the Arctic, these get counted for SIA, and so the 2012 trend line is still leading, and has been for almost a month now. Despite today's uptick I think 2012 will stay in the lead until the end of the month.
As we saw in this blog post, the CT SIA anomaly graph broke through the 2 million km2 barrier earlier than ever this year. It has shot back to 1.8 million, but given the fact that the long-term average decline is going to slow down, I wouldn't be surprised if it dips below 2 million some more before the period of re-freeze:
The current difference between 2012 and the other years is as follows:
- 2005: -857K (-76,120)
- 2006: -939K (-77,397)
- 2007: -218K (-91,629)
- 2008: -797K (-89,552)
- 2009: -867K (-99,165)
- 2010: -465K (-73,502)
- 2011: -111K (-91,469)
Between brackets is the average daily area decrease for the month of July. 2012's average daily area decrease for July is currently -86,335 square km per day. That's a big drop compared to two weeks ago (-105K), but still a lot higher than 2010, the year that also had anti-melt weather patterns in July.
Cryosphere Today area per IJIS extent (CAPIE)
CAPIE has been low, supporting the satellite images showing holes in the ice pack. These holes get counted for sea ice area, but not for sea ice extent, so if you divide the one by the other, you get a CAPIE or compactness percentage that tells you something about how patchy or Swiss-cheesy the ice pack is compared to previous years. Here's the graph:
With extent going down a bit faster in the last couple of days, and area going slower, CAPIE has gone up a bit again, but it's still really, really low for the time of year.
Percentages for July the 26th:
- 2005: 69.70%
- 2006: 71.04%
- 2007: 68.56%
- 2008: 68.64%
- 2009: 72.27%
- 2010: 66.78%
- 2011: 66.09%
- 2012: 63.44%
Regional SIE and SIA
Regional graph of the week:
I'm guessing this graph will be Regional graph of the week in more updates to come, as this is one of the few regions left that still have ice in them, together with the East Siberian Sea, Canadian Archipelago and Greenland Sea (where there's always ice because of transport from the Arctic Basin). In fact, the Arctic Basin is the biggest and most important region of all. This is where we expect the last of the ice to be, by the time the Arctic is coming close to becoming ice-free.
The trend line on the Arctic Basin SIA graph has dipped below 3 million km2, a recurring feature since 2007. Judging by this MASIE extent graph it seems to be going down faster than other years, which is hardly surprising with those holes showing up all over the place:
Most of the regions on the Regional Graphs page are practically empty of ice. The nosedive I expected on the East Siberian Sea SIA graph came about, and the Canadian Archipelago (where a lot of ice is melting in place, instead of being transported to warmer waters) is going down hard as well.
Sea Level Pressure
As usual I start with an animation of SLP images from the Danish Meteorological Institute to see what has happened in the past two weeks:
The lows dominating the Arctic, churning up and diverging that ice for the first 10 days since the last ASI update, can clearly be seen. Much of the transport towards Fram Strait was cut off, but at the same time those lows didn't move over the Canadian Archipelago either, so these effects perhaps cancelled each other out. Towards the end of the animation we see a weak high taking over and then moving in the direction of Canada. Basically things are at a standstill right now, due to a lack of intensity of both high- and low-pressure systems.
Maybe the weather forecast by the the ECMWF forecast model can tell us whether the weather will stay like this:
I would say it does seem like it will stay like this. Highs remain dominant on the American side of the Arctic, lows on the Siberian side, but I don't see anything intense that either spurs or slows the decline. For a fast decrease you need a strong high in the 1025-1035 hPa range, preferably over the Beaufort Sea. Or a nice cyclone in the 985-995 hPa range to stir things up and cause some of that flash melting that we love so much on the ASI blog because it looks so awesome.
Actually, we have been seeing some flash melting already, without that cyclone, but more on that some other time.
Temperatures
A bit more yellow and green air temperature anomalies in Siberia, a bit less in Alaska, northern Canada and Greenland, compared to two weeks ago:
When it comes to sea surface temperature anomalies (as calculated by DMI), things look again much worse than the image I posted two weeks ago for the previous ASI update:
There's significantly more red in the Laptev Sea, the red in the Kara and Barentsz Seas grew and intensified some more, and it's growing in the Beaufort Sea as well. Luckily, it seems to have cooled down a bit in the Chuckchi Sea and Bering Strait.
I'm getting increasingly worried about this. 4-5 °C warmer than on average in so many parts of the Arctic. I wonder what that will bring come September and October. If it stays like this, of course.
Update conclusion
With ice that doesn't seem to care what the weather does and warm temperatures in many places above and below the ice, it's no wonder that SIE and SIA keep decreasing steadily. This melting season doesn't resemble 2007 in any way really, but 2012 is keeping up with the tempo easily. The longer the weather stays like this, the stronger the evidence becomes that the ice is thinner than it has been for a long, long time. If it doesn't stay like this and weather patterns start to move towards something that made 2007 so formidable, we will need a word that surpasses 'formidable'.
The weather is neither fish nor flesh right now, but the ice pack keeps getting smaller, from within and without. We will know more in two weeks.
Frankd 1977, check the ASI Graphs page, top right. There you have CT SIA numbers, and the recent NSIDC SIE numbers.
As for a blog post on statistics: I don't know enough statistics for that. Maybe if I have time this weekend, I could, just like Anthony Watts, learn everything I need to know to write a paper. But I don't think so. ;-)
But I will do some sort of countdown in the ASI updates at a certain point, along the lines of: If 2012 loses as much ice as 2007, etc...
Posted by: Neven | August 02, 2012 at 02:01
On the subject on Manhattan transafers, I'd have to say http://en.wikipedia.org/wiki/Couldn%27t_Be_Hotter
Posted by: Mike | August 02, 2012 at 11:08
I've actually been maintaining precisely those stats (for SIA only; I'll do the SIE version during the freezin' season). I calculate for each year in the record how much more ice disappeared from the current day down to the minimum for that year. I then compare those numbers with the current area, and extrapolate what the minimum would be for the current year should each year's finale be repeated this year. Based on yesterday's numbers (as CT hasn't yet updated), I can tell you that 24 years in the record, and eight of the past ten, had finales that, if repeated this year, would lead to a new record. I can also tell you that the largest post-.5781 finale (1989) would bring on a minimum of 2.215 million km2 (while the smallest--1997--would result in 3.417).
If I have time over the next few days, I'll see if I can't graph this; it shouldn't be too difficult.
Posted by: Jim_pettit | August 02, 2012 at 12:34
Hi all,
CT figures:
3.92 area
anomaly -1.978
Shitbiscuits!
Posted by: idunno | August 02, 2012 at 12:56
CT area on 8/1 is lower than the annual minimum for any year before 2007.
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_N_min_to_date.png
Posted by: L. Hamilton | August 02, 2012 at 12:57
Correction, that should be CT area for 7/31. We're several days ahead of last year in passing this milestone.
http://neven1.typepad.com/blog/2011/08/the-modern-area-of-ice.html
Posted by: L. Hamilton | August 02, 2012 at 13:01
...and I spoke too soon; CT just updated, and we have another monster drop, this time about 170k km2. A few things, then:
--First, an update to the salient paragraph in my prior comment: based on today's numbers, I can tell you that 28 years in the record, and nine of the past ten, had finales that, if repeated this year, would lead to a new record. I can also tell you that the largest post-.5808 finale (1989) would bring on a minimum of 2.192 million km2 (while the smallest--1997--would result in 3.265);
--Area is now at 3.915 million km2, the earliest it's ever fallen below the 4 million mark;
--Only six years in the record have seen area drop below 4 million. It's only been 124 days since maximum was reached, by far the shortest amount of time that's taken. The average has been 157 days, and the shortest prior to this year was last year's 147 days;
--SIA is now 271k km2 less than it was on this day last year, and 355k km2 less than it was on this day in 2007;
--2012 area is still in first place for the 33rd consecutive day, and 49 of the last 54. (As noted in the previous bullet point, 2011 is in 2nd place, and 2007 is in 3rd.)
Okay, that's enough out of me for now...
Posted by: Jim_pettit | August 02, 2012 at 13:08
A few more simple comparisons in my less-is-more graphical style:
CT area on 7/31, 1979-2012:
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_N_this_date.png
Detailed comparison with record-setting 2011:
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_N_2011_2012.png
Mean daily change in July:
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_N_delta_this_month.png
Tracking the anomaly, 2007, 2011, 2012:
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_N_anomaly_to_date.png
Posted by: L. Hamilton | August 02, 2012 at 13:11
What is this going to do Monday?
Posted by: crandles | August 02, 2012 at 13:11
The Dutch have the expression "Op het vinken touw zitten", in one word, scooped. Makes it the 6th year below 4M [Jim Pettit in overtime], and 85% of sat years ending higher at their annual minimum than day ~213 of the year.
Click: http://bit.ly/CTAR01
Click: http://bit.ly/CTAANM
Click: http://bit.ly/CTNHMn
Posted by: Seke Rob | August 02, 2012 at 13:15
And CT SIA hitting nearly 2 and 3 standard deviation again on the rolling year and current day metric: http://bit.ly/CTAR02
Greenland, great clear images from DMI-MODIS of Lincoln/Kennedy/Kane for the 30th
http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/20120730TERR.jpg
http://ocean.dmi.dk/arctic/images/MODIS/Kennedy/20120730TERR.jpg
http://ocean.dmi.dk/arctic/images/MODIS/Kane/20120730TERR.jpg
Breaking up is no longer hard to do... The To Nares Speedway.
Posted by: Seke Rob | August 02, 2012 at 14:13
What a difference a hundred years makes:
http://brunnur.vedur.is/pub/trausti/Iskort/Pdf/1912/1912_08.pdf
(An interesting series of maps: you can get maps back at least as far as 1901 by changing both dates in the address-bar)
H/T Steven Goddard
Posted by: idunno | August 02, 2012 at 14:31
Idunno, this is the map directory index for easy pickins: http://brunnur.vedur.is/pub/trausti/Iskort/Pdf/
Posted by: Seke Rob | August 02, 2012 at 14:44
I guess I should have been more patient. That lag is longer than I thought. Shitbiscuits indeed.
Posted by: Neven | August 02, 2012 at 15:13
Strangelove
Strange highs and strange lows
That's how my ice goes
Posted by: Neven | August 02, 2012 at 15:17
I see quite a bit ice flashing back on the UB SIC maps, so SIA (and SIE) will probably slow down again.
IJIS SIE dropped fast in 2007 in the first week of August, so 2012 will probably play catch-up again for the rest of the month.
Posted by: Neven | August 02, 2012 at 15:54
Hi Neven, check your email.
Posted by: dabize | August 02, 2012 at 16:44
I am REALLY excited about the SIA minimum for 2012! The past 2 days have seen a decline of over 320,000 km2 (a "monster drop" as Jim Pettit called it).
As it is, 2012 is in 6th place for lowest SIA minimum in the past 34 years. The average daily SIA reduction for the past week was 72,800 km2. If the melt rate is half of that for August, a new record low will occur before the end of the month.
Jim Pettit: I am looking for daily measurements of SIA for the past few decades. I want the daily numbers and not graphs. Can you point me in the right direction?
Posted by: Frankd 1977 | August 02, 2012 at 16:49
The advice was correct go to the graphs page and look at the text links in top right box. 1st is NSIDC extent, and 5th line is CT area.
Posted by: crandles | August 02, 2012 at 16:57
Thank you crandles :)
Posted by: Frankd 1977 | August 02, 2012 at 17:09
Well, I found some time, so went ahead and drafted out the graph I spoke of above that shows the SIA decrease from the current day through the minimum for every year in the record (1979-2011), overlaid by a line showing how much area needs to drop this year in order to set a new record. As you can see, "finales" similar to all but five years in the record would result in a new record minimum this year.
GRAPH: Arctic Sea Ice Area Annual Decrease from Current Day Through Minimum
The graph will, of course, be updated daily until the beginning of melt season. And feedback is appreciated, as always...
Posted by: Jim_pettit | August 02, 2012 at 17:29
"...until the beginning of melt season."... that's going to be a long winter ;>)
Frankly, I'm not quite following your chart. Is it to indicate the amount of melt in prior years did from current day in year till their minimum?
Posted by: Seke Rob | August 02, 2012 at 17:45
>"shows the SIA decrease from the current day through the minimum for every year in the record ... feedback is appreciated"
Now we just want ;o)
http://i137.photobucket.com/albums/q210/Sekerob/Climate/CT_SIA_Annual_Minima.png
with the in progress bar broken up into a stacked bar so we get levels for:
Current year minus amount by which 17% of years reduce area from now to minimum
Current year minus amount by which 50% of years reduce area from now to minimum
Current year minus amount by which 83% of years reduce area from now to minimum
Current year as at now
(and the same for NSIDC extent ;o) ;o) )
Posted by: crandles | August 02, 2012 at 18:15
crandles: Exactly. Starting over the weekend, and then really intensifying on Monday, there will be a low centered over the Beaufort side of the CA Basin. The low is forecast to persist through mid-week, although it spreads out and moves around some.
Typical wind/wave patterns associated with low would push Chukchi ice into the Beaufort; and E. Siberian ice into the Chukchi; and CAB ice adjoining the Laptev into the E. Siberian region, opening the 'Laptev Bite'.
And a lot of the floes will melt out, or be greatly reduced in size. We could lose over 700k sq km by next Wednesday/Thursday on this side of the pack.
Posted by: Paul Klemencic | August 02, 2012 at 18:17
crandles: Exactly. Starting over the weekend, and then really intensifying on Monday, there will be a low centered over the Beaufort side of the CA Basin. The low is forecast to persist through mid-week, although it spreads out and moves around some.
Typical wind/wave patterns associated with low would push Chukchi ice into the Beaufort; and E. Siberian ice into the Chukchi; and CAB ice adjoining the Laptev into the E. Siberian region, opening the 'Laptev Bite'.
And a lot of the floes will melt out, or be greatly reduced in size. We could lose over 700k sq km by next Wednesday/Thursday on this side of the pack.
Posted by: Paul Klemencic | August 02, 2012 at 18:17
Posted by: Seke Rob | August 02, 2012 at 18:41
OK, so here a rough up for 17 and 50% with dummy values. http://bit.ly/CTNHMn
Posted by: Seke Rob | August 02, 2012 at 19:06
Crandles, a spagetti plot made from this year trajectory combined with all the previous decay trajectory would be visulay interesting.
Posted by: Yvan Dutil | August 02, 2012 at 19:25
2012 lower than all minimums before 2007
Thanks for all the great graphs everyone!
Posted by: Neven | August 02, 2012 at 19:28
PIOMAS August update: I have updated my graphics at ArctischePinguin for the July data:
Monthly data:
https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd2.png
Daily data:
https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd4.png
Daily data with a "prediction" based on exponential trend:
https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd4-1.png
Note that the 2012 volume is already 1 stdev below the minimum based on
linear trend expected for September:
https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd7.png
Posted by: Wipneus | August 03, 2012 at 06:00
Thanks Wipneus.
Interesting: both 2010 and 2011 were below the trend line in summer, then returned to it later in the year - only 2010 kept its distance to the trend line until after the minimum, while in 2011 the melt slowed down. Which way will 2012 go?
Posted by: AmbiValent | August 03, 2012 at 09:14
Mike, nice find! :)
Looks like this current Manhattan is now transferring out of the fjord rather rapidly at around 2km per day.
http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=78749
That sounds quick - what is the current pushing it out?
River-like meltwater flow?
Thermohaline?
Oceanic currents?
Wind?
Posted by: Andy Lee Robinson | August 05, 2012 at 04:20
Hi Andy.
In general, iceberg's move with their embedded ocean currents, and laugh at the wind.
Up A Lazy River...
Posted by: Artful Dodger | August 05, 2012 at 05:10
Healy is back in Dutch Harbor, Alaska for Arctic West Summer (AWSW) 2012.
Posted by: Artful Dodger | August 05, 2012 at 09:53
Record temperature at Ilulissat today. 17 °C. Preceeded by a near-record week.
Posted by: Kris | August 05, 2012 at 15:40
Despite "the storm" seems to take all of our attention, me thinks also this has to be noted:
Very unsimilar to 2007, Franz-Josef-Land has been detached completely from the central ice shelf now
Posted by: Kris | August 06, 2012 at 08:24