Arctic Sea Ice: Likely Record-Low Volume

Arctic Sea Ice Down to Second-Lowest Extent; Likely Record-Low Volume – NSIDC

The National Snow and Ice Data Center (NSIDC) says despite cooler temperatures and ice-favoring conditions, long-term decline of Arctic ice cover is continuing.

As previously reported, Arctic sea ice extent for 2008 melt season as measured by satellite was the second-lowest level since 1979, reaching the lowest point on September 14, 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million square kilometers. The record monthly low was 4.28 million square kilometers set in September 2007.

The 2008 observation strongly reinforces the thirty-year downward trend in Arctic ice extent, NSIDC said. The 2008 low was 34% below the long-term September average for the 1979 to 2000 period and only 9% greater than the 2007 record low. The 2008 low was so far below the average, it forced the negative trend in September extent downward to –11.7 % per decade (from 10.7 %).

A comparison of ice age in September 2007 (left) and September 2008 (right) shows the increase in thin first-year ice (red) and the decline in thick multi-year ice (orange and yellow). White indicates areas of ice below ~50 percent, for which ice age cannot be determined. AVHRR, SMMR SSM/I, and IABP buoy data.
—From National Snow and Ice Data Center courtesy C. Fowler, J. Maslanik, and S. Drobot, University of Colorado at Boulder – High-resolution image

“The trend of decline in the Arctic continues, despite this year’s slightly greater extent of sea ice. The Arctic is more vulnerable than ever.” —NSIDC Lead Scientist Ted Scambos

Related Links:

• Arctic ice cover second-lowest on record
• NSIDC Arctic ice extent animation

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Redoubt’s ‘Phantom Unrest’ Could Lead to Eruption

Alaska Volcano Observatory

Information Statement – Friday, October 3, 2008 10:37 AM AKDT (10:37 UTC)

Redoubt Volcano

• Type of Volcano: Stratovolcano
• Coordinates: 60°29’7″ N 152°44’38” W
• Summit Elevation: 10197 ft (3108 m)
• Recent Eruptions:1902, 1966-68, and 1989-90
• Location: Western side of Cook Inlet, about 170 km southwest of Anchorage and 82 km east of Kenai, Alaska
• Current Volcano Alert Level: NORMAL

Current Aviation Color Code: GREEN

Annotated photo of Redoubt Volcano from the north, including features seen on 27 September, 2008.
Picture Date: September 27, 2008 – Image Creator: Kate Bull – Image courtesy of the AVO/ADGGS.
Full Size

What’s up at Redoubt?

Starting September 16, reports of strong hydrogen sulfide odor and loud noises coming from the direction of the volcano were reported. AVO observation flight on September 27 revealed:

• A number of fractures and circular openings in the upper Drift glacier for the first time.
• Scientist noted a strong hydrogen sulfide odor, but onboard instrumentation recorded no sulfur dioxide.
• Fumaroles on top of  domes formed in the 1968 and 1990 eruptions showed more vigorous steaming than the last observation in mid-August.
• AVO’s seismic network detected no abnormal earthquake activity, despite the earlier reports.

AVO believes Redoubt’s increased fumarolic activity and presence of sulfur odors do not suggest an imminent eruption, despite similar observations being made in the  months preceding the 1989-1990 eruption, when seismicity also increased significantly. AVO expects a similar strong increase in seismicity first before an eruption occurs.

Notes:

In the 1989-90 eruption lahar traveling down the Drift River partially inundated the Drift River Oil Terminal facility. Ash plumes produced during the same eruption affected international air traffic with traces of ashfall falling on Anchorage and nearby communities. (AVO)