PIOMAS June 2016
8
June, 2016
Another
month has passed and so here is the updated Arctic sea ice
volume graph as
calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation
System (PIOMAS) at the Polar
Science Center:
As
of May 31st the 2016 trend line is lowest on the graph. A sea ice
volume decrease of 3037 km3 during the month of May was enough to
overtake 2011 and increase the lead over every other year in the
2007-2016 period, except for 2010 and 2012, which both recorded
massive volume losses during May. 2016 has a very small lead now over
2011 (162 km3) and 2012 (270 km3). The gap with last year has grown
to a whopping 2180 km3.
Here's
how the differences with previous years have changed since last
month:
Wipneus' version of the PIOMAS volume graph also shows how close the 2011, 2012 and 2016 trend lines are:
The
trend line on the PIOMAS sea ice volume anomaly graph has now dipped
well below the linear trend, moving towards the 2 standard deviation
zone where it hasn't been since 2013:
As
for thickness, I still can't use Cryosphere Today sea ice area data
for my crude thickness calculation (PICT), as they haven't switched
to the new SSMIS-based data yet (it's still in the calibration phase)
and so I've decided to use reliable AMSR-2 based data as provided by
JAXA (via ADS-NIPR).
I divide PIOMAS volume by JAXA sea ice extent to get average
thickness that I can then compare to previous years. I've decided to
use a serious acronym this time: PIJAMAS.
Here's
the graph:
One
would intuitively guess that when volume is low, average thickness is
low too. But when the ice cover is even lower - and JAXA SIE was much
lower than previous years at the end of May - the volume gets spread
out over a smaller area, and thus average sea ice thickness is now
higher than other years from the post-2010 era.
Another
interesting piece of information has been added to the PIOMAS
website, a thickness anomaly map that
shows where this year the ice is thicker/thinner compared to the
2000-2015 average:
This
reminded me of the volume distribution comparison maps that Wipneus
produces every month and shares on
the Arctic Sea Ice Forum. Because this year is so close to 2011 and
2012, I decided to have a look at the differences with these two
years (red means there is more ice now than there was then, blue the
reverse):
As
you can see, according to the PIOMAS model there is more ice this
year mainly in the Central Arctic and in the East Siberian Sea, the
difference being more pronounced in 2011. Sea ice volume is
practically on a par with 2011 and 2012 as of the end of May. These
are also the years that ended in the lowest September volume and
extent numbers.
If
we assume that volume in the Central Arctic doesn't matter for the
September sea ice extent minimum (as it didn't melt in 2011 and 2012
when sea ice volume was lower there), this means that sea ice volume
is lower outside of the Central Arctic, in the regions that do matter
for the outcome of the melting season.
As
eyeballing only gets you so far, I asked Chris Reynolds about this
(be sure to check out his latest blog
post on
PIOMAS and other data) and he was so kind as to send me the PIOMAS
volume numbers for the Central Arctic and the rest of the Arctic:
This
year is on a par with 2011 both within and outside of the Central
Arctic region, but looking again at Wipneus' thickness difference
map, it's clear that the East Siberian Sea will play crucial role in
the race between 2011 and 2016. This region is in the middle of a
heatwave as we speak, and the ice surface is showing extensive
melting, according to satellite images and other data (I'll have more
on this next week).
As
for 2012, this year there is 1000 km3 less sea ice volume in the
regions outside of the Central Arctic. That's a lot of ice - almost
10% - that doesn't need to melt for this year to end on a par with
2012. Most of this difference is situated in the American-Pacific
side of the Arctic, where the ice pack opened up at record speed this
year and large stretches of open water are in the process of warming
up, next to and within a large part of the ice pack that is looking
increasingly patchy.
According
to both PIOMAS and CryoSat the ice seems to be thicker in the
currently warm East Siberian Sea than it was in 2012, but in contrast
to 2011, there's also somewhat thicker ice on the Atlantic side of
the Arctic. The Atlantic seems to be bringing warmer ocean currents
to the Arctic this year, so it remains to be seen what will happen to
that ice. All in all, 2016 looks to have a slight advantage over
2012, when it comes to potential melting in the regions outside of
the Central Arctic.
This
is all fine and well, speculating is fun, but June was when 2012 laid
the basis for its record breaking melt, due to almost perfect weather
conditions for melting. June has been more modest this year so far,
but there's three more weeks left to go. We'll know next month
whether this year will have been able to keep up with 2012's
breakneck pace.
Atmospheric CO2 Reaches
New High, Arctic Ice Shrinks
to New Low
8
June, 2016
The
atmospheric concentration of carbon dioxide reached a new high of
407.7 parts per million, a 3.76 ppm increase since last May, as
measured at
the Mauna Loa Observatory in Hawaii.
According
to the National Oceanic and Atmospheric Administration, the planet
last saw such an increase in carbon dioxide between 17,000 and 11,000
years ago.
Last
month, Arctic
ice levels hit
a record low, with the average area of sea ice on the Arctic Ocean
being just 4.63 million square miles, according
to the
National Snow and Ice Data Center. This follows previous record lows
set this year in January, February and April.
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