| 基于海豹观测的阿拉斯加湾东部陆坡海域逆温现象及其衰退机制 |
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| 引用本文： | 郭绍敬,靖春生,张善武,王维波.基于海豹观测的阿拉斯加湾东部陆坡海域逆温现象及其衰退机制[J].海洋学报,2022,44(6):48-57. |
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| 作者姓名： | 郭绍敬 靖春生 张善武 王维波 |
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| 作者单位： | 1.自然资源部第三海洋研究所，福建 厦门 361005 |
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| 基金项目： | 国家重点研发计划（2016YFC1402607）； |
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| 摘 要： | 利用2014年3–4月北象海豹携带的自动温盐深仪（CTD-SRDL）在阿拉斯加湾东部陆坡海域上采集到的温盐剖面数据，分析了该海域逆温现象的空间分布和演变过程。结果显示，研究海域存在明显的逆温现象，逆温幅度和逆温厚度范围分别介于0.2~1.6?C和20~280 m之间，前者沿陆坡向北幅度逐渐增大，后者在50?~58?N间往北逐渐变厚，在58?N以北海域平均厚度较薄。3月25日至4月22日，逆温层处于衰退阶段。逆温层下界温度不断下降，逆温幅度呈变弱趋势，逆温厚度呈变薄趋势。一维扩散模型模拟结果表明，湍扩散作用下，观测期间海表受热导致混合层上部位温升高，但底部仍保持低温，因此逆温层上界温度变化并不明显。次表层由于具有强的位温梯度，湍扩散导致逆温层下界温度显著降低，是观测期间逆温衰退的主要原因。湍扩散作用导致次表层水体温盐属性趋于均匀，这一过程对于阿拉斯加湾逆温现象的形成及演变研究具有重要意义。
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| 关 键 词： | 阿拉斯加湾 逆温现象 湍扩散 |
| 收稿时间： | 2021-06-15 |
Temperature inversion and its decline over the eastern continental slope in the Gulf of Alaska based on seal observation |
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| Institution: | 1.Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China2.Fujian Provincial Key Laboratory of Marine Physical and Geological Processes, Xiamen 361005, China |
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| Abstract: | Hydrographic data collected from March to April 2014 by CTD-SRDL mounted on northern elephant seal were analyzed to study the distribution and decline of the temperature inversion over the eastern continental slope in Gulf of Alaska. The results show that temperature inversion occurred significantly in this region. Temperature difference was between 0.2°C and 1.6°C and thickness of temperature inversion was between 20 m and 280 m, respectively. The temperature difference increased northward along the continental slope, while the thickness thickened from 50°N to 58°N, but the average thickness at north of 58°N was relative thinner. The temperature inversion was decay during March 25 to April 22, 2014. The subsurface maximum temperature continued to fall, the temperature difference tended to be weaker, and the thickness presented a thinning tendency. Numerical results of a one-dimensional model reveal that, the temperature at the upper mixed layer increased by heating on the sea surface, but the temperature at the bottom of the mixed layer remained low, therefore the minimum temperature of temperature inversion change was not notable. With a strong temperature gradient in the subsurface, the subsurface maximum temperature dropped pronouncedly due to the turbulent diffusion, which is the main reason for temperature inversion decline. Turbulent diffusion modified temperature and salinity in subsurface water to be uniform, thus it is important to study this process for the formation and evolution of temperature inversion. |
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