北极加拿大海盆2003年和2008年上层海洋热含量的差异分析

VARIATION OF UPPER-OCEAN HEAT CONTENT IN THE CANADA BASIN IN SUMMERS OF 2003 AND 2008

主要利用2003年和2008年两次夏季北极科学考察的CTD数据处理了加拿大海盆上层海洋(指200 m以浅)的热含量,定量分析了热含量随深度的变化,并比较分析了这两年在夏季海冰融化期间热含量的垂向差异变化,以及影响热含量变化的因素,给出了上层海洋热含量在加拿大海盆的空间分布。2008年与2003年相比最显著的变化是在加拿大海盆开阔水域的增加,导致了太阳辐射能进入海洋中的能量增加,同时海冰的大量融化带来了大量淡水,这些变化改变了上层海洋的温盐性质。海冰大量融化主要产生两个效应:一是上层海洋的普遍增暖,二是太平洋入流水体的下移。文中还分析了近年来在加拿大海盆中变化显著的次表层暖水现象,由于次表层暖水蕴含着不小的热含量,其在上层海洋热量平衡中的作用不容忽视。

Conductivity,temperature,and depth data collected during the summers of 2003 and 2008 were used to study upper-ocean（top 200 m） heat content in the Canada Basin.The variation of heat content with depth,heat content differences between the summers,principal driving factors,and horizontal spatial scale differences,were analyzed.A catastrophic reduction of sea ice cover in the Canada Basin was evident in 2008 compared with 2003,suggesting that more solar radiation was absorbed in the upper ocean during the summer of 2008.The sea ice reduction produced more fresh water in the upper ocean.Thus,sea water properties changed.The study shows that the huge reduction in sea ice would result in two changes-a widespread warming of the upper ocean,and a substantial increase in the depth of Pacific inflow water to the basin.The near-surface temperature maximum（NSTM） water was also analyzed as an indicator of Arctic Ocean warming.