May 26th 2013
This is a slow start in two ways.
I wanted to begin posting ASI updates a couple of weeks earlier, but had the idea to try and make video versions of them to save time, as it took me an average 3-4 hours last year to write an update (gazing at graphs and satellite images not included). But I've never made videos before, and it takes me a while to get over the psychological barrier to do new things. So after fiddling with settings for a while and trying stuff out, I realized a couple of things, leading to this video:
Luckily, my slow start wasn't a problem, as the Arctic melting season has a slow start itself, just like last year. At least, when it comes to area and extent numbers.
We know, based on the latest PIOMAS update and the 2012/2013 Winter Analysis I did a couple of weeks back, that 2013 so far looks pretty similar to 2012, except perhaps for the initial configuration, with thicker ice on the Siberian side of the Arctic instead of in the Beaufort Sea.
I can repeat one part of the Winter Analysis, as my opinion hasn't changed:
Despite a couple of differences, this melting season looks similar to last year's melting season and so it will probably beat the 2007 records. Whether it will also beat last year's records is too early to tell, as weather is still an important factor. We used to see rebounds in the Arctic whenever a record low was hit (also known as 'recovery! recovery!' on fake skeptic blogs), but I'm not sure how bouncy the Arctic is anymore.
The start is slow, just like last year. The why and whereto is explained below.
Sea ice area (SIA)
I've decided to start the ASI 2013 updates with Cryosphere Today sea ice area. Except perhaps for the period when melt ponds fool sensors into thinking there's more open water than there actually is (leading to lower SIA numbers), I think it has become a more useful metric than sea ice extent, for the simple fact that the pack is fragmenting more and more and a lot of information isn't therefore properly conveyed anymore by extent, because it glosses over the open spaces between floes.
Here's the graph based on the latest data:
With a series of five consecutive century breaks at the end of last month it looked as if the melting season was off to a flying start, but things have slowed down considerably and the 2013 trend line is now just slightly below that of 2009, almost 350K above 2012 and even more than 500K above other years.
One thing I'm not doing this year, is displaying the exact numerical differences with previous melting seasons. Instead I'm now uploading my spreadsheets to GoogleDrive for you to download if you're interested in the details. I think the spreadsheets are reasonably accurate (or else give a shout, but not about the way CT dates their stuff, because that drives me insane) and pretty self-explanatory. Hope you don't mind the Open Office format.
Here's the link to my CT SIA spreadsheet.
Even though AMSR2 still seems a bit jumpy, IJIS remains an old favourite. Here's the graph:
The current trend line is the highest in the 2005-2013 period. 2012 was highest last year as well in the first week of June, but then started a precipitous drop that never really ended, despite a long period of weather conditions that weren't conducive to extent decrease.
Here's the link to my IJIS SIE spreadsheet.
Regional SIE and SIA
Regional graph of the week, taken from the Regional Graphs page:
I'm very surprised at this graph, as I was expecting a rapid drop right off the bat. The water in Baffin Bay heated up big time last year, and temperatures have been anomalously high since the start of the year. But nothing in the Arctic is a dead certainty and so, after a very early drop, things have remained pretty stable and the anomaly trend line is real close to zero. The air temperature graph further below shows what happened, but I'm still amazed.
Sea Level Pressure (SLP)
Here's an animation of Danish Meteorological Institute SLP images for the last two weeks to get an idea of what's been going on:
In the first half of the animation we see how a high pressure area moves about over the Siberian coast. This could be one of the reasons for a large polynya opening up in the Laptev Sea. It reminds me a bit of 2007 around this time of year, but we saw the same thing last year as well, of course (see the Concentration Maps page for May 25th).
In the second half of the animation we see another high forming over the American side of the Arctic, over the Canadian Archipelago. This hasn't had any effect. Yet.
Let's see what the 6-day weather forecast by the ECMWF model has in store (click for a larger version):
My attention immediately gets drawn to a low pressure area in the middle of the Arctic Ocean. With a pressure of 990 hPa it obviously doesn't come close to the Great Arctic Cyclone of 2012, but it's still pretty low for this time of the year. It's also quite persistent for a cyclone, sticking around for 4-5 days in practically the same spot. It's the cyclones that do the most churning and diverging, so it will be interesting to see what this will have done to the ice pack as soon as the clouds move away.
In the meantime the highs are over on that American side of the Arctic and with the Sun less than a month away from the Solstice this means lots of sunshine. If things stay that way for a prolonged period, we can expect many melt ponds and a rerun of last year's show.
So now we come to the main reason behind this melting season's slow start. For the past 30 days things have been anomalously cold over the American side of the Arctic (and Greenland as well) according to NOAA/ESRL/NCEP:
I think we all expected that the cracking event of last February and March in the Beaufort Sea would lead to a very rapid melt, but it seems the cold has managed to delay the onslaught and the lead (pun intended) 2013 had over 2012 seems to have vanished.
The anomalous warmth was over the Siberian side, but as the ice is allegedly thicker over there compared to last year, this hasn't automatically led to a drop in SIA and SIE numbers.
We also see the cold around Greenland reflected in the DMI 80N temp graph:
Going up, up, up and then crash. Now going up again, but still below average.
There still is a lot of ice, but some red is already showing up on the DMI SST anomaly maps in the Barentsz Sea:
For comparison: Here's how things looked last year towards the end of August. Hopefully it won't be as bad this year.
Based on the numbers we could say that the melting season is having a slow start, but the ice is thin in many places and satellite images are already showing potential zones of divergence well into the pack.
This situation reminds me a bit of something I read in a great gardening book called Gaia's Garden: A Guide To Home-Scale Permaculture. Towards the end of the book the author describes how a permaculture garden, after a few years of muddling and getting various elements set up, suddenly goes POP.
Suddenly everything falls into place, perennial plants have finally taken sufficient root to start expanding for real, beneficial bugs and birds have made their home, and the garden starts to thrive on its own.
I feel the Arctic sea ice pack could soon go POP under the right conditions.
Patrick Lockerby is also back with a piece: Arctic 2013