摘要
以固态形式存在的冰冻圈诸要素,其冻、融过程导致水循环发生重要变化,进而影响大洋、河流水文过程及大气水分循环过程.本文在分析两极地区海洋淡水组成的基础上,论述了两极地区冰冻圈对大洋输入淡水的影响,阐释了冰冻圈与大洋热盐环流的关系,讨论了冰冻圈对海平面上升的贡献程度.研究指出,在南、北纬60o^90o范围南、北极海洋的淡水年循环中,海冰和北极融雪参与的水量远超过降水-蒸发过程的水循环量;北极融雪与河流补给、山地冰川、冰帽及格陵兰冰盖、南极冰盖、海冰、冰间湖等冰冻圈要素的变化可以显著地影响海洋深水对流强度及深水的形成,从而影响海洋热盐环流.冰冻圈对海平面变化影响的评估仍然存在较大的不确定性.从1990年开始的5次IPCC评估报告中,历次对海平面上升贡献的评估结果相差较大.总体来看,若不考虑陆地水储量变化的影响,在海洋热膨胀和冰冻圈这两大影响因子中,工业化升温以来对海平面上升的贡献各占一半.
Freeze-melt processes of the cryosphere have important impacts on hydrological processes of oceans and rivers, as well as the atmospheric water cycle. Based on analysis of the composition of freshwater in oceans of the polar regions, the effect of the cryosphere on freshwater input to polar oceans is analyzed. Further, the relationship between the cryosphere and ocean thermohaline circulation is interpreted and the cryosphere contribution to sea level rise is discussed. In the freshwater cycle of the Antarctic and Arctic oceans from 60° to 90° latitude, Arctic sea ice and snow meltwater greatly exceeds water in the precipitation-evaporation process in the water cycle. Arctic snowmelt, river recharge, mountain glaciers, ice caps and the Greenland ice sheet, as well as changes in cryosphere elements such as the Antarctic ice sheet, sea ice, polynya and others, can significantly affect the strength of deep water convection and thereby the ocean thermohaline circulation. Assessment of cryospheric impact on sea level change still has great uncertainty. Ignoring the impact of changes in land water storage, the contributions to sea level rise of thermal expansion by ocean warming and the cryosphere are nearly the same since industrialization, and the projected contribution of the cryosphere will exceed that of thermal expansion to sea level rise,
出处
《科学通报》
EI
CAS
CSCD
北大核心
2015年第7期593-602,共10页
Chinese Science Bulletin
基金
国家重大科学研究计划(2013CBA01808)
国家自然科学基金重点项目(41030638)资助
关键词
冰冻圈
水循环
水文影响
海洋环流
海平面变化
cryosphere, water cycle, hydrological effect, ocean circulation, sea level change
