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Sunday, January 23, 2011

Joseph Romm: Canada sees staggering mildness as planet’s high-presure record is “obliterated”; Stu Ostro explains how global warming is changing the weather

Ostro explains how global warming is changing the weather

by Joseph Romm, Climate Progress, January 23, 2011

Temperature anomalies in North America, 12.10-1.11
Surface temperature anomalies for the period December 17, 2010, to January 15, 2011, show impressive warmth across the Canadian Arctic….
The largest anomalies here exceed 21 °C (37.8 °F) above average, which are very large values to be sustained for an entire month.
The disinformers and many in the media love to focus on where it is cold in the winter.  It has been cool where many people live.  Brr!

Unfortunately for homo sapiens, it’s been staggeringly warm where the ice is.  I’ll do a post on Greenland shortly, but the NSF-sponsored researchers at UCAR/NCAR  have posted some staggering data on just how warm it has been in northern Canada:
To put this picture into even sharper focus, let’s take a look at Coral Harbour, located at the northwest corner of Hudson Bay in the province of Nunavut. On a typical mid-January day, the town drops to a low of –34 °C (–29.2 °F) and reaches a high of just –26 °C (–14.8 °F). Compare that to what Coral Harbour actually experienced in the first twelve days of January 2011, as reported by Environment Canada (see table at left).
  • After New Year’s Day, the town went 11 days without getting down to its average daily high.
  • On the 6th of the month, the low temperature was –3.7 °C (25.3 °F). That’s a remarkable 30 °C (54 °F) above average.
  • On both the 5th and 6th, Coral Harbor inched above the freezing mark. Before this year, temperatures above 0 °C (32 °F) had never been recorded in the entire three months of January, February and March.
The extremes have been just as impressive when you look high in the atmosphere above these areas. Typically the midpoint of the atmosphere’s mass—the 500-millibar (500 hPa) level—rests around 5 kilometers (3 miles) above sea level during the Arctic midwinter. In mid-December, a vast bubble of high pressure formed in the vicinity of Greenland. At the center of this high, the 500-mb surface rose to more than 5.8 kilometers, a sign of remarkably mild air below. Stu Ostro (The Weather Channel) found that this was the most extreme 500-mb anomaly anywhere on the planet in weather analyses dating back to 1948. Details are at the conclusion of Ostro’s year-end blog post. 
Farther west, a separate monster high developed over Alaska last week. According to Richard Thoman (National Weather Service, Fairbanks), the 500-mb height over both Nome and Kotzebue rose to 582 decameters (5.82 km). That’s not only a January record: those are the highest values ever observed at those points outside of June, July and August.
Previously I wrote about how Weather Channel expert Stu Ostro discussed Georgia’s record-smashing global-warming-type deluge:  “Nevertheless, there’s a straightforward connection in the way the changing climate “set the table” for what happened this September in Atlanta and elsewhere. It behooves us to understand not only theoretical expected increases in heavy precipitation (via relatively slow/linear changes in temperatures, evaporation, and atmospheric moisture) but also how changing circulation patterns are already squeezing out that moisture in extreme doses and affecting weather in other ways.”

In January, Ostro explained at great length in a long PPT, “A connection between global warming and synoptic meteorology,” which is a must-read for wonks.  In December, Stu Ostro explained:
HOLY 500 MILLIBAR HEIGHT ANOMALY, BATMAN! In recent years, I’ve documented many cases of strong ridges of high pressure aloft which have contributed to temperature and/or precipitation extremes, as those pressures aloft have risen in recent decades in tandem with the warming of the atmosphere. 
Well, recently the atmosphere outdid itself. At the peak of the pattern which begat the wild weather in Europe and the U.S., the biggest departure from average pressure aloft in the database (which goes back to 1948) anywhere on the planet occurred over Greenland on December 15. Then the next day that record was smashed. And the previous record for December at this level, a few miles above the Earth’s surface, was completely obliterated. 
This image is simply a copy and paste from a spreadsheet which ranked all of the departures in that database. (Technically they’re “positive 500 millibar height anomalies.”) But what it represents is significant. 

[Data source: ESRL; NCEP/NCAR Reanalysis 1]
The UCAR/NCAR analysis continues:

The year the sea forgot to freeze

Arctic sea ice extent, 12.21.10
Large areas of open water persisted across much of the area between Greenland and Canada on December 21, 2010. (Image courtesy Cryosphere Today.) 
Why so freakishly mild?  One factor that both feeds and is fed by the warmth is the highly unusual amount of open water across seas that are normally frozen by late November. On the winter solstice (December 21), Hudson Bay was little more than half frozen (see map at right). 
Similarly, a large swath of the Baffin/Newfoundland Sea fell weeks behind schedule in freezing up. As evident in the charts at bottom, these bodies of water remain in catch-up mode. Around the south part of Baffin Island, “the boats were still in the water during the first week of January,” says David Phillips, a senior climatologist with Environment Canada. “The Meteorological Service of Canada was still writing marine forecasts as of 7 January, well beyond anything we have ever done.” 
Storm after storm sweeping up the East Coast in recent weeks has pumped warm Atlantic air across eastern Canada, helping postpone the freeze-up even further and allowing temperatures over land to soar far above average.
According to Philips, the implications for people in the far north have been widespread. Nunavut’s capital, Iqaluit, had to cancel its year-end snowmobile run on Frobisher Bay for the first time. “Last New Year’s Eve, the big story was ice breaking up,” says Phillips. “This year there was no ice to break up.” 
Worst of all, he adds, “it’s impossible for many people in parts of the eastern Arctic to safely get on the ice to hunt much-needed food for their families—for the second winter in a row. Never before have we seen weather impact a way of life in so many small and big ways.”
Now imagine how warm it is going to be in the Arctic when during these kinds of heat waves are compounded by several decades of global warming:
Graphic of chnage in temperature
How could the Greenland ice sheet possibly survive?

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