Summit County Citizens Voice

Spring northern hemisphere snow cover extent has been dropping rapidly for 15 years.

Arctic air temps soaring well above average

By Summit Voice

SUMMIT COUNTY — Along with the heat wave gripping a large part of the lower 48 states, some exceptional mid-June warmth in the far north helped speed Arctic sea to some record daily low levels in mid-month.

The ice extent on June 30 (3.70 million square miles) would not normally be expected until July 21, based on 1979-2000 averages. This puts extent decline three weeks ahead of schedule.

While weather patterns over the Arctic varied widely, air temperatures in the area stayed above the 1981 to 2010 average by as much as 7.2 degrees, and as much as 12.6 to 16.2 degrees above average over northern Eurasia and near southern Baffin Bay.

Researchers observing the ice pack reported daytime highs reaching 66 degrees near Barrow, Alaska, causing ice the area to melt at the rate of about 4.3 in a single 24- hour period, according to preliminary data. The melting was exacerbated by a layer of nighttime fog that trapped heat near the surface and bright afternoon sunshine.

Overall, Arctic sea ice declined at near-record pace for the month to the lowest total coverage since 2010. According to the National Snow and Ice Data Center the June 2012 sea ice extent was one of the three lowest on record during the satellite era, dating back to 1979.

The ice extent was about 54,000 square miles above the 2010 record low. The only area where the sea ice extent is still above average is along the east coast of Greenland.

Through 2012, the linear rate of decline for June Arctic ice extent over the satellite record is 3.7 percent per decade.

Snow cover extent in the northern hemisphere also retreated quickly in May and June, continuing a steady trend of snow melting earlier in the year. June 2012 set a a new record low for snow extent (for a 45-year period of record spanning 1967-2012) by a significant margin.

For the year, the snow cover extent was the third-lowest for the 45-year period. The earlier loss of snow exposes large, darker underlying surfaces to the sun early in the season, fostering higher air temperatures and warmer soils.

Filed under: climate and weather, Environment, global warming Tagged: | Measurement of sea ice, National Snow & Ice Data Center, Polar ice packs