['pɜ:məfrɔst] 名词 This HTML5 player is not supported by your browser 强调
一般 вечная мерзлота ; вечномёрзлый грунт (a thick subsurface layer of soil that remains below freezing point throughout the year. COED. permafrost, permanently frozen soil, subsoil, or other deposit, characteristic of arctic and some subarctic regions; similar conditions are also found at very high altitudes in mountain ranges. In 1962 measurements in a borehole drilled on Melville Island, Northwest Territories, Canada, showed that the ground was frozen to a depth of at least 1,475 ft (450 m); comparable thicknesses have been found in other far north regions. Tundras, though underlaid by permafrost, today support centers of population in Alaska, Canada, and Siberia. Permafrost is a very fragile system that may easily be damaged or destroyed by the presence of man-made heat. A controversy developed in the late 1960s and early 70s over the construction of an oil pipeline from the Alaska North Slope to the southern part of the state. Critics of the project argued that if the pipeline containing hot oil ever came into contact with the permafrost, it would melt the permafrost; the pipeline would then sink and eventually break. The oil spilled during the breakage would result in a major ecological disaster. It was decided to build the pipeline with insulated pipe raised above the permafrost or on gravel beds in order to prevent melting and thus preserve both the pipeline and the ecosystem. The Columbia Electronic Encyclopedia® Copyright © 2013 Alexander Demidov 军队, 技术 вечномёрзлые породы 地质学 мёрзлые отложения (MichaelBurov ; мёрзлая толща (MichaelBurov 建造 многолетняя криолитозона ; вечномёрзлый грунт 技术 многолетняя мерзлота ; многолетнемёрзлый грунт 油田 многолетнемёрзлые горные породы 海洋学 вечная мерзлота (почвы) 生态 многолетнемёрзлые породы 石油/石油 многолетнемёрзлая горная порода 石油和天然气技术 вечномёрзлая порода 自然资源和野生动物保护 мерзлотная почва ; многолетно мёрзлый материал ; постоянно мёрзлый грунт ; почва с вечно мёрзлым слоем 钻孔 многолетнемёрзлая порода 马卡罗夫 вечная мерзлота (состояние почвы) ; многолетнемёрзлые породы (явление длительного охлаждения горных пород до нулевой температуры и сами горные породы, оцементированные замёрзшей в них влагой, называемые многолетнемёрзлыми породами) 黄金开采 вечная (многолетняя мерзлота Leonid Dzhepko 油和气 ММГ (многолетний мерзлый грунт OGC 地质学 вечномерзлотный (MichaelBurov ; многолетнемёрзлый (MichaelBurov ; геокриологический (MichaelBurov ; вечномёрзлый (palomnik 英语 词库 缩写 permanently frozen ground 缩写, 地球科学 permanently frost
