The observational and numerical study on the impact of the Amur to the Okhotsk sea ice

阿穆尔河对鄂霍茨克海冰影响的观测与数值研究

基本信息

批准号：
12573006
负责人：
TACHIBANA Yoshihiro
金额：
$ 3.46万
依托单位：
TOKAI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

项目摘要

PurposesThe Sea of Okhotsk(OK), which is located between the Sibeiian continent and the North Pacific, is covered by ice from November through June, and is one of the southernmost ice-covered oceans in the Northern Hemisphere. The interannual variability of the sea-ice in the OK is large and sea-ice coverage has abniptly decreased since the end of the 1980's. Also, the sea-ice influences large scale climate such as the development of the Aleutian low and the formation of the Noiih Pacific intermediate waters 8-10. In analogy with the Arctic Ocean, sea-ice in the OK has been believed to be influenced by the ground hydrological processes. Previous studies suggest the existance of a highly siralilied, low-salinity surface layer in the OK, which suppresses deep convection and promotes freezing. It has also been speculated that the low-salinity layer is mainly due to the inflow of the fresh water from the Amur River. Although previous studies attempted to find evidence of the river-water in … More fluence on the sea-ice using data analyses, the lack of reliable interannual data for sea-ice precluded direct comparison between the ice-data and the discharge-data Because the period of reliable satellite-based ice-data has become long enough to analyze the inteninnual variability, we are now able to directly compare the two. The purpose of our study is to collect the Amur discharge data and to quantify the effects of the Amur discharge on the sea-ice on interannual and longer time scalesResultsThe impacts of ground hydrology on the high-latitude oceans, such as melting glaciers and discharge from rivers in the oceans, can affect global climate by mediating the flow of low-density, fresh water inflow that strengthens the ocean's stratification, suppresses the thermohaline circulation and also promotes sea-ice formation. Ourtime series analysis based on sea-ice and river-discharge data indicates that the effect of this fresh water on the sea-ice in the Sea of Okhotsk, into which the second largest Siberian River, the Amur, discharges, is relatively unimportant Interannual variations in the ice extent are negatively correlated with the amount of discharge. We find evidence that the inflow of wanner river water tends to the raise of the sea surface temperature, and that it suppresses ice formation in the following winter. These findings imply that sensible heat transported by large rivers in high latitudes should be reconsidered in studying global climate change. Less

目的鄂霍次克海（OK）位于西伯利亚大陆和北太平洋之间，从11月到6月被冰覆盖，是北半球最南端的冰雪覆盖海洋之一，年际变化较大。俄克拉何马州的海冰面积很大，自20世纪80年代末以来海冰覆盖范围急剧减少，而且海冰还影响着大范围的气候，例如海洋的发展。阿留申低压和北太平洋中间水域的形成与北冰洋类似，OK 地区的海冰被认为受到地面水文过程的影响。低盐度表层，抑制深层对流并促进结冰，也有人推测，低盐度层主要是由于阿穆尔河淡水流入所致。以前尝试通过数据分析来寻找河水对海冰影响的证据，但由于缺乏可靠的海冰年际数据，无法对冰数据和排放数据进行直接比较，因为该时期基于卫星的冰数据已经足够长，足以分析年际变化，我们现在能够直接比较两者，我们研究的目的是收集阿穆尔放电数据并量化阿穆尔放电对大气的影响。海冰上年际和更长的时间尺度结果地面水文学对高纬度海洋的影响，例如冰川融化和海洋河流的排放，可以通过调节低密度淡水流入加强海洋的分层来影响全球气候，抑制温盐环流并促进海冰形成我们基于海冰和河流排放数据的系列分析表明，这种淡水对海冰的影响。鄂霍次克海的海冰相对不重要，而西伯利亚第二大河阿穆尔河的排放量则相对较小。冰范围的年际变化与排放量呈负相关。我们发现有证据表明，温纳河的流入量呈负相关。河水趋于升高海面温度，并抑制接下来的冬季结冰。这些发现意味着，在研究全球气候变化时，应重新考虑高纬度地区大河流的感热输送。