|
An ice pier is a man-made structure used to assist the unloading of ships in Antarctica. It is constructed by pumping seawater into a contained area and allowing the water to freeze. By repeating this procedure several times, additional layers are built up. The final structure is many metres in thickness, and strong enough to support container trucks. Operation Deep Freeze personnel constructed the first floating ice pier at Antarctica’s southernmost sea port〔(U.S. Polar Programs ) National Science Foundation FY2000.〕 at McMurdo Station in 1973.〔("Unique ice pier provides harbor for ships," ) Antarctic Sun. January 8, 2006; McMurdo Station, Antarctica.〕 Ice piers have been in use each summer season since, at McMurdo’s natural harbor at Winter Quarters Bay located at . The harbor is positioned on the southern tip of Ross Island. Historically, two supply ships, a freighter and a tanker, arrive at the ice pier each summer, after an icebreaker opens a ship channel through pack ice. The ice pier’s key function is to provide a platform for freight trucks to come alongside a supply ship to receive or offload cargo. Steel cables attached to shoreline hold the dock in a fixed position. Port officials distribute freight arriving at the dock to McMurdo Station, nearby Scott Base, and to field camps as far away as the South Pole. Imports include virtually any materials needed to support personnel living and working in Antarctica. Exports range from items such as scientific ice core samples and human waste collected from field camps to broken equipment and recyclables for return to the United States for processing. Ice piers typically have a lifespan of three to five years. Once an ice pier is no longer usable, icebreakers tow the pier to sea to be cast adrift. ==Annual break-in opens ship channel== Ships docking at the McMurdo Station ice pier rely upon icebreakers opening a ship channel from Upper McMurdo Sound to Winter Quarters Bay. One or more icebreakers, depending upon seasonal conditions, will typically open a channel from eight to long.〔(“Polar Star Duties,” ) Seattle Post-Intelligencer. December 1999.〕 However, in 2005 icebreakers encountered more than of pack ice blocking entry to McMurdo Sound.〔("U.S., Russian icebreakers open path to Antarctic base," ) USA Today. February 6, 2005〕 The ice buildup occurred when a 100-mile-long iceberg (B15A) ran aground near Upper McMurdo Sound. Two icebreakers eventually broke a ship channel through to Winter Quarters Bay. The ship channel provides a seaway for the few annual re-supply vessels and research ships which call upon the extraordinarily remote seaport at McMurdo Station. Preparation for the supply ships’ arrival includes icebreakers maintaining a uniform edge on the seaward side of the pier. The ship’s skipper maneuvers the icebreaker to use its bow as a giant battering ram to scarf or shave jagged edges from the pier to facilitate ships tying up at the dock.〔 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「ice pier」の詳細全文を読む スポンサード リンク
|