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McMurdo Sound and its ice-clogged waters extends about long and wide. The sound connects the Ross Sea to the north with the Ross Ice Shelf cavity to the south via Haskell Strait. The strait is largely covered by the McMurdo Ice Shelf. The Royal Society Range rises from sea level to on the western shoreline. Ross Island, an historic jumping-off point for polar explorers, designates the eastern boundary. The active volcano Mt Erebus at dominates Ross Island. Antarctica's largest scientific base, the United States' McMurdo Station, as well as the New Zealand Scott Base are on the southern shore of the island. Less than 10 percent of McMurdo Sound's shoreline is free of ice. It is the southernmost navigable body of water in the world. Captain James Clark Ross discovered this sound, which is about from the South Pole, in February 1841, and he named it after Lt. Archibald McMurdo of the HMS ''Terror''. The sound today serves as a resupply route for cargo ships and for airplanes that land on the floating ice airstrips near the McMurdo Station. However, McMurdo Station’s continuous occupation by human beings since 1957/58 has dirtied the harbor of Winter Quarters Bay. The pack ice that girdles the shoreline at Winter Quarters Bay and elsewhere in the sound presents a formidable obstacle to surface ships. Vessels require ice-strengthened hulls and often have to rely upon escort by icebreakers. Such extreme sea conditions have limited access by tourists, who otherwise are appearing in increasing numbers in the open waters of the Antarctic Peninsula. The few tourists who reach the McMurdo Sound find spectacular scenery with wildlife to be seen, including killer whales, seals, Adelie penguins, and emperor penguins. Cold circumpolar currents of the Southern Ocean reduce the flow of warm South Pacific or South Atlantic waters reaching McMurdo Sound and other Antarctic coastal waters. Bitter katabatic winds spilling down from the Antarctic polar plateau into McMurdo Sound demonstrate Antarctica's status as the coldest and windiest continent in the world. The McMurdo Sound freezes over with sea ice about thick during the winter. The Antarctic summer causes the pack ice to break up. Wind and currents may push the ice northward into the Ross Sea, stirring up cold bottom currents that spill into the ocean basins of the world. Temperatures during the dark winter months at McMurdo Station have dropped as low as . However, December and January are the warmest months, with average highs at , according to USA Today. ==Ice defines strategic role== McMurdo Sound's role as a strategic waterway dates back to early 20th century Antarctic exploration. British explorers Ernest Shackleton and Robert Scott built bases on the sound's shoreline as jumping-off points for their overland expeditions to the South Pole. McMurdo Sound's logistic importance continues today. Aircraft transporting cargo and passengers land upon frozen runways at Williams Field on the McMurdo Ice Shelf. Moreover, the annual sealift of a cargo ship and fuel tanker rely upon the sound as a supply route to the continent's largest base, the United States' McMurdo Station. Both the U.S. base and New Zealand's nearby Scott Base are on the southern tip of Ross Island. Ross Island is the southmost piece of land in Antarctica that is accessible by ship. In addition, the harbor at McMurdo's Winter Quarters Bay is the world's southmost seaport (Department of Geography, Texas A&M University). The access by ships depends upon favorable ice conditions. McMurdo Sound during austral winter presents a virtually impenetrable expanse of surface ice. Even during summer, ships approaching McMurdo Sound are often blocked by various concentrations of first-year ice, fast ice (connected to the shoreline), and hard multi-year ice. Subsequently, icebreakers are required for maritime resupply missions to McMurdo Station. Nonetheless, ocean currents and fierce Antarctic winds can drive pack ice north into the Ross Sea, temporarily producing areas of open water. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「McMurdo Sound」の詳細全文を読む スポンサード リンク
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