The upper ocean thermohaline structures in the region of the Chukchi Plateauare analyzed with the hydrographic data collected by the Chinese National Arctic Research Expeditionin the summer of 2003. Three types of the...The upper ocean thermohaline structures in the region of the Chukchi Plateauare analyzed with the hydrographic data collected by the Chinese National Arctic Research Expeditionin the summer of 2003. Three types of the Pacific-origin water were found in the upper ocean,Alaska Coastal Water (ACW), summer Bering Sea Water (sBSW) and winter Bering Sea Water (wBSW) areindicated by two maximums temperature and one minimum temperature, piling up from the upper to thelower respectively. The extreme warm ACW with a maximum temperature of 1.62℃ was found in thesouthwestern Canada Basin at a depth of about 50 m. A pathway of the ACW into the basin from itsadjacent area did not existed in the expedition period. So it is speculated that the extreme warmfeature of the ACW was formed locally in 2003. The relative weak ACW occurred to the east of theChukchi Cap and in the southern Chukchi Abyssal Plain. The latter one might originate from a warmdownwelling that existed in a small canyon at the shelf break of the Chukchi Sea. The sBSW withoutthe ACW was found only at the southwestern flank of the Chukchi Cap. The ACW and the sBSW were notfound in the northernmost station at 81°N,which indicates the north boundary of the upperPacific-origin water in the Canada Basin. The wBSW, which existed in all deep stations, was exactlyuniform at temperature. The difference of the core potential temperature of the wBSW in the deepregions is only 0.08℃.展开更多
对楚科奇海中部沉积物岩芯中的硅藻进行鉴定,共发现52属97种。运用聚类分析方法可将该岩芯分为3个硅藻带。5-3.5 cal ka BP期间海冰硅藻含量较高但有明显的下降趋势,硅藻丰度不断上升并达到峰值,表明此期间太平洋暖水流入楚科奇海加速...对楚科奇海中部沉积物岩芯中的硅藻进行鉴定,共发现52属97种。运用聚类分析方法可将该岩芯分为3个硅藻带。5-3.5 cal ka BP期间海冰硅藻含量较高但有明显的下降趋势,硅藻丰度不断上升并达到峰值,表明此期间太平洋暖水流入楚科奇海加速了海冰退缩,促进了楚科奇海中部海域海洋生产力的发展。淡水种含量在此阶段有所增加,表明阿拉斯加沿岸流对楚科奇海中部海域海洋环境的影响增强。3.5-1.3 cal ka BP时期硅藻丰度持续降低表明楚科奇海浮游生物生产力减弱,这与太平洋水流入减少、海冰覆盖增加有一定的关联。而来自于阿拉斯加沿岸流携带的淡水硅藻含量较低,表明此时阿拉斯加沿岸流势力减弱。1.3-0 cal ka BP期间,海冰硅藻含量波动上升,硅藻丰度处于较低水平,表明全新世晚期白令海入流减弱,海冰覆盖范围有所扩大。楚科奇海中部中全新世以来的沉积硅藻记录表明,太平洋暖水流入的强弱变化与研究区的海冰覆盖情况,共同控制着研究区的海洋生产力变化。展开更多
基金supported by the National Natural Science Foundation of China under contract Nos 40306005 and 40376007.
文摘The upper ocean thermohaline structures in the region of the Chukchi Plateauare analyzed with the hydrographic data collected by the Chinese National Arctic Research Expeditionin the summer of 2003. Three types of the Pacific-origin water were found in the upper ocean,Alaska Coastal Water (ACW), summer Bering Sea Water (sBSW) and winter Bering Sea Water (wBSW) areindicated by two maximums temperature and one minimum temperature, piling up from the upper to thelower respectively. The extreme warm ACW with a maximum temperature of 1.62℃ was found in thesouthwestern Canada Basin at a depth of about 50 m. A pathway of the ACW into the basin from itsadjacent area did not existed in the expedition period. So it is speculated that the extreme warmfeature of the ACW was formed locally in 2003. The relative weak ACW occurred to the east of theChukchi Cap and in the southern Chukchi Abyssal Plain. The latter one might originate from a warmdownwelling that existed in a small canyon at the shelf break of the Chukchi Sea. The sBSW withoutthe ACW was found only at the southwestern flank of the Chukchi Cap. The ACW and the sBSW were notfound in the northernmost station at 81°N,which indicates the north boundary of the upperPacific-origin water in the Canada Basin. The wBSW, which existed in all deep stations, was exactlyuniform at temperature. The difference of the core potential temperature of the wBSW in the deepregions is only 0.08℃.
文摘对楚科奇海中部沉积物岩芯中的硅藻进行鉴定,共发现52属97种。运用聚类分析方法可将该岩芯分为3个硅藻带。5-3.5 cal ka BP期间海冰硅藻含量较高但有明显的下降趋势,硅藻丰度不断上升并达到峰值,表明此期间太平洋暖水流入楚科奇海加速了海冰退缩,促进了楚科奇海中部海域海洋生产力的发展。淡水种含量在此阶段有所增加,表明阿拉斯加沿岸流对楚科奇海中部海域海洋环境的影响增强。3.5-1.3 cal ka BP时期硅藻丰度持续降低表明楚科奇海浮游生物生产力减弱,这与太平洋水流入减少、海冰覆盖增加有一定的关联。而来自于阿拉斯加沿岸流携带的淡水硅藻含量较低,表明此时阿拉斯加沿岸流势力减弱。1.3-0 cal ka BP期间,海冰硅藻含量波动上升,硅藻丰度处于较低水平,表明全新世晚期白令海入流减弱,海冰覆盖范围有所扩大。楚科奇海中部中全新世以来的沉积硅藻记录表明,太平洋暖水流入的强弱变化与研究区的海冰覆盖情况,共同控制着研究区的海洋生产力变化。
