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Posts tagged Alaska

The Role of Bering Strait in Regulating the Global Climate

65.4N 169.9W

June 18th, 2013 Category: Climate Change AVHRRMetOp

Russia and USA – June 17th, 2013

Alaska’s Bering Strait may play a critical role in the regulation of the global climate — including a knack for maintaining the Atlantic Ocean “conveyor belt” that bathes northern Europe in sultry currents and warm wet weather.

But squeeze shut the 53-mile-wide narrows between the Pacific and Arctic oceans off the western tip of Alaska — something that occurred during the last ice age when continental ice sheets locked up much of the world’s fresh water — and the oceanic engine that stabilizes the home planet’s climate becomes much more likely to go on the fritz and stay that way for a long time.

These resulting shutdowns have previously stalled the Gulf Stream and triggered abrupt swings between warmer and frigid climates, what scientists call Dansgaard-Oeschger and Heinrich events. These jarring shifts struck the North Atlantic as many as 25 times between 80,000 and about 11,000 years ago, all during moments when the Bering Land Bridge blocked all flow between Pacific and Arctic oceans.

The flow of the Gulf Stream and other elements of the global ocean circulation system deliver warm salty water to the North Atlantic, where it cools, grows denser, and sinks. At depth, this dense salty water starts flowing south. It then keeps rolling, eventually crawling into other hemispheres along a network of deep ocean currents that meander the globe over hundreds of years while equalizing the climate.

But introduce massive amounts of less dense fresh water into the mix, and the North Atlantic sinking starts to sputter, slowing the deep currents to the point where they temporarily die. The paradoxical result can be a chilldown of northern Europe and perhaps the entire northern hemisphere. Thus, smooth functioning of the Atlantic ocean “conveyor” becomes a “critical link” in keeping the world’s climate from making these wild swings (click here for more information).

Climate Change and Alaska’s Bodies of Water, USA – May 29th, 2013

64.2N 149.4W

May 29th, 2013 Category: Climate Change, Image of the day

USA – May 28th, 2013

Several bodies of water along the coast of Alaska, USA, can be viewed here: Cook Strait, brownish grey with sediments (right), Bristol Bay (below, center) and Norton Sound, partially ice covered (upper left).

Global warming is currently impacting Alaska and will continue to impact it a number of ways. These impacts include melting polar ice, the retreat of glaciers, increasing storm intensity, wildfires, coastal flooding, droughts, crop failures, loss of habitat and threatened plant and animal species.

According to scientists, Arctic sea ice extent in 2012 was the lowest since satellite records began in 1979; it was 16 percent lower than the previous low in 2007 and more than half of what it was in 1979. Less ice means more open water – which means greater absorption of solar energy – which leads to increased warming in the ocean, and in turn accelerates more ice loss.

This has led to a wide range of impacts in Alaska, including: melting glaciers, rising sea levels, and flooding of coastal communities; thawing permafrost, increased storm severity, and related infrastructure damage to roads, utility infrastructure, pipelines and buildings; loss of the subsistence way of life as animal habitat and migration patterns shift and as hunting and fishing become more dangerous with changing sea and river ice; forest fires and insect infestations increasing in frequency and intensity (click here for more information).

Bristol Bay and Ahklun Mountains, Alaska, USA

57.9N 160.6W

March 6th, 2012 Category: Mountains

USA - January 3rd, 2012

This wide-swath ASAR image shows Bristol Bay, the eastern-most arm of the Bering Sea, in Southwest Alaska, USA. Bristol Bay is 400 km (250 mi) long and 290 km, (180 mi) wide at its mouth. A number of rivers flow into the bay, including the Cinder, Egegik, Igushik, Kvichak, Meshik, Nushagak, Naknek, Togiak, and Ugashik. Here, a layer of ice, appearing light grey, can be seen over some of the waters.

Visible north of the bay are the Ahklun Mountains, in the northeast section of the Togiak National Wildlife Refuge in southwest Alaska. They support the only existing glaciers in western Alaska, and are the highest Alaskan mountain range west of the Alaska Range and north of the Alaska Peninsula. To the west of the range is the Kuskokwim River and to the east is the Bristol Bay lowlands.

Mount Cleveland Volcano and Islands of the Four Mountains, Alaska, USA – October 31st, 2011

52.8N 169.9W

October 31st, 2011 Category: Image of the day, Volcanoes

USA - October 29th, 2011

This orthorectified image shows the Islands of Four Mountains, an island grouping of the Aleutian Islands in Alaska, United States. The chain includes, from west to east, Amukta, Chagulak, Yunaska, Herbert, Carlisle, Chuginadak, Uliaga, and Kagamil Islands.

This island chain is located between Amukta Pass and the Andreanof Islands to the west, and Samalga Pass and the Fox Islands to the east. These islands have a total land area of 210.656 sq mi (545.596 km²) and have no permanent population.

The two largest islands are Yunaska and Chuginadak. Chuginadak is mainly made up of the active volcano Mount Cleveland, a nearly symmetrical stratovolcano on the western end the island. Mount Cleveland is 1730 m high, and one of the most active of the 75 or more volcanoes in the larger Aleutian Arc. Mount Cleveland erupted three times in 2009, twice in 2010, and once in 2011.

Phytoplankton Bloom in Bristol Bay Near Alaska Peninsula

57.8N 160.8W

August 25th, 2011 Category: Phytoplankton

Phytoplankton Near Alaska, USA - August 25th, 2011

The bright teal stain in Bristol Bay, near the Alaska Peninsula, is a phytoplankton bloom (click here for previous images). Subsurface phytoplankton blooms are relatively common in Bristol Bay (particularly from mid August to early September).

Bristol Bay is the eastern-most arm of the Bering Sea, in Southwest Alaska. Bristol Bay is 400 km (250 miles) long and 290 km, (180 miles) wide at its mouth. A number of rivers flow into the bay, including the Cinder, Egegik, Igushik, Kvichak, Meshik, Nushagak, Naknek, Togiak, and Ugashik. Upper reaches of Bristol Bay experience some of the highest tides in the world.

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