Saturday, 23 May 2015

Arctic sea ice conditions worsen

Arctic Sea Ice Conditions Worsen, Nightmare Melt Scenario in the Works?


22 May, 2015
It’s the end of a bad week in a bad month in a bad season in the all-too-bad, human-heated, era for Arctic sea ice. As of the middle of this week, both the US measure — NSIDC — and Japan’s measure — JAXA — were showing record low daily sea ice extents. The lowest levels in the history of Arctic sea ice observation for this time of year and likely the lowest levels for hundreds, even thousands of years.
As charts go, the JAXA graphic looks pretty amazingly ominous. A 2015 sea ice extent line diving below all others, steadily plumbing an abyss that, if not this year or the next, could lead to a dreaded blue ocean event in the not-too-distant future. The kind of upshot from human greenhouse gas emissions we thought we might see by 2080 or later. One that has become increasingly more likely during recent years and that some researchers are expecting could emerge by before 2020.

Sea ice extent
(JAXA sea ice measure plunging to new record lows on May 22 and now hitting a very steep angle of decline. Image source: JAXA Polar Research.)

Above you can seen the 2015 red line taking its most recent plunge after hovering very near to record low levels. According to JAXA’s Polar Research Center, sea ice extent dropped like a stone to 11.44 million square kilometers yesterday, or about 200,000 square kilometers lower than the previous record low value set in 2006.
Divergence in May

The problem is not just one of a new record low. It’s one of timing and divergence. Accelerated melt in the May-to-June time-frame can have serious impacts on late season ice. The reason is that greatly reduced ice coverage also reduces albedo or reflectivity. The result can be compounded warming and increased heat absorption by darker surfaces under the 24 hour Arctic sunlight of June and July.
Large open stretches of ocean also enable swell formation, which can chew away the ice. And already we can see very large sections of dark, low albedo, ocean forming throughout many vulnerable regions.
Arctic ice visual May 22
(MODIS satellite shot shows widespread regions of open ocean and far northward melt advance for this time of year. Image source: LANCE-MODIS.)

For this time of year, we have very advanced sea ice loss and open ocean development in the regions of the Chukchi, the Beaufort, Northern Baffin Bay and the Kara. In addition, large open water areas are now becoming visible in the Laptev. A far northern extent of sea ice melt for May in addition to typical seasonal losses coming from Hudson Bay and southern Baffin Bay.
Such record low ice totals at this time of year can enable far greater melt advance by end season if the weather stacks up in all the wrong ways. And, at least for the next week, the weather forecast is tilting ever more heavily toward a melt-enhancing extreme warming of Arctic regions.
Arctic Warm Air Invasion Forecast to Continue

Over the next seven days, heat is predicted to continue to flood from south to north — goaded along by high amplitude ridges in the Jet Stream continuing to form over Northwestern North America and the Siberian region adjacent to the Kara Sea. The warm flux zones are forecast to deliver unseasonable, above average temperatures to the Arctic — resulting a general state of much warmer than normal conditions for the entire Arctic Ocean by late next week.
Air Temperature Anomaly ArcticAir Temperature Arctic May 29
(Side-by-side comparison of Arctic temperature anomaly forecast [left] and 2 meter temperature forecast [right] for May 29, 2015 in the GFS model run as provided and graphically displayed by Climate Reanalyzer. It’s worth noting that such extreme anomalies are very unusual for Arctic Ocean regions during late spring and summer.)

As a result, we see temperature anomalies for the entire Arctic Ocean zone hitting a range of between 5 and 15 degrees Celsius above average for next Friday (May 29, 2015). Such a warm air surge would push temperatures in the above freezing range for almost the entire Arctic Ocean area. These are temperatures more typical of late June and early July. Conditions that, should they emerge, would result in a multiplication of ice-threatening melt ponds, a further expansion and warming of already unseasonably large open water zones, and a forcing of more ice-eating, high heat content water vapor into the Arctic environment.
Any forecast is subject to uncertainty. Rapid May melt during 2013 and 2014 stalled out during June of those years. However, May melt is significantly more advanced this year than during those years. And, as opposed to 2013 and 2014, GFS model forecasts showing warmer than normal conditions have tended to be correct. The warm air slots over Northwest North American and Western Siberia are also very well established at this time.
Melt Ponds Barrow May 22

(Snow cover gone, melt ponds plainly visible at Barrow Alaska today. Proliferation of melt ponds during May and June can greatly enhance risk of record low totals come August and September. Image source: Barrow Sea Ice Cam.)

As a result, there’s high risk that the current record lows now appearing in the NSIDC and JAXA measures with continue to deepen over the coming week. It’s an utterly wretched situation for sea ice in the Northern Hemisphere. One that will bear very close watching as the risks now appear to be heading toward some unsettling markers.
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