Topic(s):Climate, Cryosphere, Hydrosphere, Oceans
Scenario:In search of the Northwest Passage... The fate of Franklin no man can know The fate of Franklin no tongue can tell Lord Franklin with his seamen does dwell." Verse from "Lord Franklin" an English Ballad. Listen to the ballad. In spite of being one of the best equipped expeditions and carrying five years of food supplies, Franklin and 128 members of his crew perished in the Arctic. The sea ice surrounding King William Island didn't melt enough in the summer of 1847, keeping Franklin's ships trapped through the following winter. Franklin died on June 11, 1847. In the spring of 1848 the remaining 105 members of the expedition abandoned their ships, camped on the island and eventually perished. The search for Franklin and the Northwest Passage contributed to the mapping and exploration of Canadian Arctic waterways and the identification of several possible Passage routes. Nearly fifty years later, Roald Amundsen, who later beat Scott to the South Pole, became the first to navigate the Northwest Passage sea-to-sea in 1903-1906. It took Amundsen two years to pick his way through the ice-laden waters of the Arctic. Like Franklin and others before him, his ships often became trapped in the sea ice for long periods of time. In the absence of the sea ice, navigating the Passage would be quick and easy. If the record-setting melt of Arctic sea ice in 2007 in any indication of things to come, ships sailing in open water through the Northwest Passage could soon become a daily, year round event. Sea ice forms when a frigid air mass above the sea surface chills the surface seawater to its freezing point. It starts out as single ice crystals. The ice crystals bunch together into clusters called frazil or grease ice. Eventually the clusters begin to freeze together forming a thin continuous sheet (nilas). The sheet gets thicker as additional ice forms at the edges and on the underside of the nilas. Wind and waves force the nilas together to form bigger sheets that float on the surface (pancake ice). There are differences in the accumulation and distribution of sea ice in Earth's Northern and Southern polar regions. Accumulation and distribution are controlled by the differences in the influx of solar radiation due to the tilt of the Earth's rotational axis, distribution of land masses, distribution, temperature and circulation of water masses and atmospheric and oceanic seasonal characteristics. The extent of sea ice varies greatly with the seasons. When it's winter in Arctic, it's summer in the Antarctic. Arctic sea ice reaches its maximum extent (~14 million square kilometers) in March, melts to its minimal extent (~7 million square kilometers) in September and has an average thickness of ~3 meters. Antarctic sea ice reaches its maximum extent (~20 million square kilometers) in September and melts to its minimum extent (~4 million square kilometers) in February. The amount of sea ice lost in Southern regions during the summer melt (~16 million square kilometers) is about equal to the land area of South American. Arctic sea ice is generally older and thicker than that in the Antarctic. Prior to the late 1970's the information about the extents and concentrations of sea ice in our polar regions came from visual observations by ship and aircarft crews, explorers and researchers and native peoples. Since then, remote sensing through the development and deployment of satellites equipped with passive microwave radiometers has provided data to produce detailed polar images for identifying and tracking sea ice extents, concentrations and floes. Analyses of sea ice extent data (satellite since 1978) included in the International Government Panel on Climate Change (IPCC) Climate Change 2007 Synthesis Report indicate that sea ice extent is shrinking: North polar sea ice at a rate of decrease of ~3% per decade; South polar sea ice at rate of little more than 1% per decade. How fast and far-reaching the implications of the changes in sea ice will be is still open to some debate. But according to the IPCC Fourth Assessment Summary Report, climate models indicate that sea ice extent is projected to continue to shrink in both the Arctic and Antarctic. Some projections indicate that Arctic sea ice could disappear entirely by the end of this century. Satellite and pre-satellite records indicate that the Arctic has not been been free of summer ice for at least 5,000 and possibly 125,000 years. Earth's climate system and ecosystem did not develop in conjunction with an ice-free Arctic. An ice-free summertime Arctic could have significant and unforeseen ramifications for climate change and ecosystems. Recent changes in the extent of summer Arctic sea ice could suggest that the long sought-after Northwest Passage will become accessible for long periods of time in the future. In September of 2007, the Northwest Passage was reported to be totally free of ice for first time since satellite monitoring began. Commenting on the unexpected opening of the Passage, Mark Serrenze, a senior scientist at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado said: "We're probably 30 years ahead of schedule in terms of the loss of the Arctic sea ice.".
Task:
Date: 3/25/2009 |
Scenario Images:
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Resources:
1. All About Sea Ice
(Cycle A)
2. Scientific Background for Studying Polar Sea Ice Processes
(Cycle A)
3. Arctic Sea Ice News Fall 2007
(Cycle A)
4. Arctic Climate Impact Assessment Reports
(Cycle A)
5. Climate Change Classroom Activities
(Cycle A)
6. Readings
(Cycle A)
7. Sea Ice Extent and Concentration Data Sets and Animations
(Cycle A)
1. Arctic Climate Change: Where Reality Exceeds Expectations
(Cycle B)
2. Arctic Sea Ice 2007 Minimum: An Autopsy
(Cycle B)
3. Climate of 2007
(Cycle B)
4. Arctic Sea Ice News
(Cycle B)
5. Sea ice: a refuge for life in polar seas?
(Cycle B)
6. Readings
(Cycle B)
1. Exploring the Cyrosphere Using Data from the National Snow and Ice Data Center
(Cycle C)
2. Simple Science
(Cycle C)
3. Sea ice - An Antarctic habitat
(Cycle C)
4. Global Climate Change Student Guide
(Cycle C)
5. Climate Literacy: "The Essential Principles of Climate Sciences"
(Cycle C)
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Sample Investigations:
Snow and Ice I and II
(Cycle A)
Virtual Globes: NSIDC Data on Google Earth
(Cycle A)
Difficulty: intermediate More advanced learners: use the dataset, imaging, and animation resources listed in cycle A to create your own animations and graphs for analysis.
March of the Polar Bears: Global Change, Sea Ice, and Wildlife Migration
(Cycle B)
Polar Regions: Arctic Adaptations and Global Impacts
(Cycle B)
Northwest Passage - Google Earth
(Cycle C)
Studying Snow and Ice Changes
(Cycle C)
Wither Arctic Sea Ice?
(Cycle C)
Standards:
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