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Mechanism of Environmental Variability in the Arctic Ocean

北冰洋环境变化机制

基本信息

批准号：
11309001
负责人：
IKEDA Motoyoshi
金额：
$ 20.04万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11309001/
关键词：
the Arctic Ocean global warming sea ice variability at a decadal period plant plankton ocean chemistry 北極圏生物化学物理結合系気候変動

项目摘要

As a platform to integrate the entire project, we have developed a coupled ice-ocean model of the Arctic, by which the responses of the ice-ocean system to the atmospheric variability are examined, and also bio-geochemical processes are interpreted in the physical-biogeochemical version. Once the atmospheric pressure pattern is given the Arctic Oscillation (AO) signal, the model has reproduced the observed sea ice cover variability at a decadal period. The water exchange through the Fram Strait is found to increase responding to the intensified Polar Vortex. Deep convection and dense water spreading are the important oceanic processes which are not explicitly resolved in the Arctic model, and are parameterized on the basis of high resolution models. An observational study has provided better understanding of under-ice mixing.The further analysis of the Arctic model has revealed the feedback mechanisms, by which the Arctic Oscillation and ice-cover variability could enhance each other. … More Once the ice cover reduces, more heat is given to the atmosphere, which tends to intensify the Polar Vortex. Its wind pattern increases the water exchange through the Fram Strait and gives favor to the Atlantic Water penetrating into the Arctic Ocean. Then, more sea ice melts. This positive feedback comes together with a self-oscillating system of the Arctic-Atlantic Ocean, and excites the AO.Cloud and radiation data collected by the Soviet Union have been analyzed to present a cloud increase in the recent 40 years. This effect on the surface heat flux is equivalent to that arising from the albedo decrease due to the ice reduction. Although the sea ice has been claimed to be an important indicator for global warming in the real climate and global warming simulation, it has been strongly suggested that more parameters than sea ice and temperature should be looked into carefuly in the comparison between observed data and model results.Bio-geochemical processes are important environmental components and also crucial to global warming through feedback to the physical component. Observations have been conducted in the Bering Sea, Baffin Bay, the Baltic Sea and Saroma Lagoon, identifying a primary species of phytoplankton in each area. Their roels for global warming have been estimated.Hydrochemical data collected by the Soviet Union include dissolved oxygen, alkalinity, phosphate, nitrate and silicate. This data set has been analyzed, giving an evidence of vertical stretching of the water column in the Canada Basin. The vertical motion can be interpreted as a consequence of Ekman convergence or divergence responding to the AO. This striking result is expressed as the most recent outcome of this project. Less

作为整合整个项目的平台，我们开发了一个北极冰-海洋耦合模型，通过该模型研究了冰-海洋系统对大气变率的响应，并在物理-生物地球化学版本中解释了生物地球化学过程。一旦大气压力模式得到北极涛动（AO）信号，该模式就能重现观测到的海冰覆盖在十年周期内的变化。通过弗拉姆海峡的水交换随着极地涡旋的增强而增加。深对流和密集水扩张是北极模式未明确解析的重要海洋过程，在高分辨率模式的基础上进行了参数化。一项观测研究提供了对冰下混合的更好理解。对北极模式的进一步分析揭示了北极涛动和冰盖变率相互增强的反馈机制。一旦冰盖减少，更多的热量被传递给大气，这往往会加剧极地涡旋。它的风型增加了通过弗拉姆海峡的水交换，有利于大西洋的水渗透到北冰洋。然后，更多的海冰融化。这种正反馈与北冰洋-大西洋的自振荡系统结合在一起，激发了AO。对苏联收集的云和辐射数据进行了分析，发现近40年来云量有所增加。这种对地表热通量的影响相当于由于冰的减少而引起的反照率的降低。尽管海冰在真实气候和全球变暖模拟中被认为是全球变暖的重要指标，但有人强烈建议，在观测数据和模式结果的比较中，应该仔细研究海冰和温度以外的更多参数。生物地球化学过程是重要的环境组成部分，并通过反馈到物理组成部分对全球变暖至关重要。在白令海、巴芬湾、波罗的海和萨罗马泻湖进行了观察，在每个地区确定了一种主要的浮游植物。它们对全球变暖的影响已经被估计出来了。苏联收集的水化学数据包括溶解氧、碱度、磷酸盐、硝酸盐和硅酸盐。对这组数据进行了分析，给出了加拿大盆地水柱垂直伸展的证据。垂直运动可以解释为响应AO的Ekman辐合或辐散的结果。这个惊人的结果被表示为这个项目的最新成果。少