(Arctic sea surface temperature anomaly on June 24, 2014. Image source: NOAA/NWS.)
For
encircling the Arctic from the West Coast of Greenland, to Iceland,
to Svalbard, to the Barents and Kara Seas, to the Chukchi and on to
the Beaufort we see surface water temperatures ranging from 2.25 to 4
C or more above average. And just west of Svalbard, we have water
temperatures ranging in a zone exceeding a terrifying 8 C above
average. When a sea surface temperature departure of 0.5 to 1 C above
average is considered significant, these values represent extremes
that are far outside what was once considered normal.
Melt
Pressure to Ice Sheets
Such
high surface water temperatures have numerous effects. The first is
that adjacent submerged ice sheets, such as the calving faces of
Greenland’s great glaciers plunging into the ocean, are faced with
a far greater melt pressure than before. The glacial fronts in many
cases expose 500 or more feet of ice directly to these much warmer
waters. And on almost every side of Greenland, but especially in the
west, along Baffin Bay, these great ice masses are confronting
extraordinary warmth. The heating is without respite. It occurs at
all hours of the day and since it is delivered by water, it is many
times more energy intensive than a similar volume of equally heated
air.
Widespread
Sea Ice Thinning and Melt
In
the sea ice edge zone, the warmth also provides added heat pressure
to the vulnerable and already greatly thinned ice floes. This heating
is especially apparent in areas where continental rivers disgorge
their waters into the Arctic Ocean. Warmer than normal water
temperatures have coincided with much warmer than normal land
temperatures, particularly over tundra regions like Canada’s
Northwest Territory and the Yakutia region of Russia. These warmer
lands result in warmer river flows. And the hot rivers spill into an
already hotter than usual Arctic Ocean.
The
result, as we can see in today’s MODIS satellite shots are numerous
zones of greatly thinned ice.
(Ice melt, thin ice and melt ponds in the Beaufort Sea on June 25 of 2014. Image source:LANCE MODIS.)
A
Beaufort Sea confronted with warm water outflow from the Mackenzie
River, sea surface temperatures in the range of +1 to +4.5 C above
average, and a broad swath of above freezing air temperatures, is now
starting to show major melt effects. The sea ice has already
withdrawn by as much as 150 miles from a broad section of the
Canadian and Alaskan coasts. The off-shore ice features numerous very
large polynyas and leads. And, overall, the ice has taken on a bluish
tint indicative of widespread melt pond formation.
(Arctic Sea Ice over the Laptev and East Siberian Seas. Image source: LANCE MODIS.)
Meanwhile
on the far side of the Arctic, effects appear to be even more
widespread. Though sea surface temperature values are somewhat lower
than those seen in the Beaufort, at +0.5 to +1.25 in most open water
areas, the entire region is rife with 150-200 mile wide polynyas,
shattered and broken floes, and thinning (blue in the satellite
picture) ice covered in melt ponds. The ice in this region is so
frail that even the mildest storms, featuring 15-20 mph winds, are
enough to rip through and splinter previously contiguous ice. And the
storms in the region this year have been quite mild, ranging from 990
to 1000 mb in strength.
Sea
ice measures show current area and extent at between 3rd and 5th
lowest on record. That said, observed ice response to even the
mildest high and low pressure weather systems reveals a startling
vulnerability with much warmer than normal sea surface temperatures
surely a contributing factor.
Wildfire
Eruptions From The Northwest Territory to Siberia
In
net, much warmer water temperatures and retreating sea ice in the
Northern Hemisphere trigger both Jet Stream erosion and increasing
south to north air flow. Over the continents, where lands are far
more susceptible to rapid warming, this can result in Arctic regions
seeing summer time temperatures comparable to those in latitudes much
further south.
Over
the past week, temperatures in the upper 70s to upper 80s
(Fahrenheit) covered a broad region of Canada’s Northwest Territory
including Alberta and the Mackenzie Delta region along the Beaufort
Sea. These temperatures, in the range of 20-25 F above average
rapidly dried out the shallow topsoil zone over the frozen and
thawing tundra. Such rapidly dried soil and newly liberated tundra is
a volatile fuel for fires. The human-thawed tundra itself contains
burnable organic material and hosts pockets of methane while the dry
soil bed is suffused with tinder-like grasses and shrubs. Any
ignition can set off extraordinary fires of almost unimaginable scope
and intensity.
(Massive fires rage near Great Slave Lake in Canada on June 24, 2014. Image source:LANCE MODIS.)
By
June 24, four massive fires, each with a front ranging from 20-30
miles in breadth, raged along the shores of Great Slave Lake in
Northwest Canada. Four smaller, though still significant fires also
burned nearby. The fires are plainly visible as white, comet-like
plumes of smoke in the satellite picture above. For reference, Great
Slave Lake is more than 200 miles across at its widest point. Bottom
edge of frame is about 300 miles.
To
the south and east by about 250 miles lies the Fort McMurray tar
sands operation. A smaller, though still intense, tundra fire raged
within 20 kilometers of that sprawling site but did not yet encroach
on one of the most powerful and dangerous means of
carbon-to-atmosphere delivery on the planet.
On
the other side of the Arctic in Siberian, Russia, the situation was,
once again, more dire. There a region very vulnerable to mid summer
wildfires during recent years erupted into numerous blazes belching
smoke into a swirling cloud caught up in the heat dome overhead:
(Massive region of wildfires North of Lake Baikal, Russia. Image source: LANCE MODIS.)
These
fires were sparked by temperatures that, during recent days, ranged
in the 80s and even 90s. An extraordinary heat forcing for rapidly
melting tundra regions that also saw far warmer than typical
temperatures this past winter.
This
area, about 800 miles to the north of Lake Baikal, Russia, is a
region of rapidly thawing tundra that has burned again and again
during recent summers. For scope, the satellite shot frame, above, is
750 miles on an edge. In the picture are about 50 fires with fronts
ranging from 4-35 miles.
Smoke
and soot from these massive fires are swept up in the circumpolar Jet
Stream. There they are born aloft for hundreds of miles, often
traveling northward to find a final resting place upon the sea ice or
atop Greenland’s glaciers. This ultimate darkening of the snow
further enhances glacial melt even as it completes the cycle of
warmth, finishing a dance of heat that rises up from the oceans,
assaults the ice, and heats the once frozen lands to erupt in flame.
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