LTO学术报告2022-24

报告题目一:Leading-Mode Connections of the Inter-annual Variability in Upper-Ocean Salinity in the Tropical Indian Ocean
报告人:黄科,中国科学院南海海洋研究所,热带海洋环境国家重点实验室,副研究员

报告人简介:黄科,博士毕业于中国科学院大学,曾在美国缅因大学、澳大利亚联邦科学与工业研究组织访问,2018年担任中国科学院南海海洋研究所副研究员。研究方向主要涉及:热带海洋环流、海气相互作用和生态环境变化。在Journal of Physical Oceanography, Journal of Geophysical Research: Oceans, Deep Sea Research II等国际SCI刊物发表论文20余篇。担任Journal of Climate, Journal of Physical Oceanography等十余种SCI杂志同行评审。

报告摘要:Leading modes of inter-annual variability in upper-ocean salinity in the tropical Indian Ocean (TIO) and their connections were studied based on 17 years (2002–2018) of oceanic historical and reanalysis data. Empirical orthogonal function (EOF) analysis depicted the dominant roles of the first two leading modes in salinity variability in the TIO over a wide range of inter-annual timescales. Among the rich oscillations of the leading EOF modes, a coherent near-biennial band was identified with basin-wide loading of sea surface salinity anomalies (SSSa) (EOF1) leading/lagging the northeast–southwest dipolar mode of SSSa (EOF2) by around 4 months across the TIO, with southwestward migration of SSSa center. The spatial loadings of the SSSa leading modes in the TIO were strongly shaped by sea surface temperature–related freshwater fluxes and wind-driven regional ocean circulation on a near-biennial timescale. Composite analysis of the mixed-layer salinity budget reflected characteristic features of basin-scale ocean–atmosphere coupling, both temporally and regionally during the life cycle of the near-biennial fluctuation in anomalous salinity in the TIO. Consistent with the intrinsic oscillation paradigm in the observed Indian Ocean Dipole (IOD) variation, the dynamic and thermodynamic feedbacks associated with switches from the positive to negative IOD modes provided the phase-connection mechanisms for the SSSa leading-mode displacement over the TIO.

 

报告题目二:Subsurface Cooling in the Tropical Pacific Under a Warming Climate
报告人:鞠汶姗,中国科学院南海海洋研究所2020级博士研究生

报告人简介:鞠汶姗,中国科学院南海海洋研究所2020级博士研究生,研究方向为太平洋温盐及环流结构对全球变暖的响应。

报告摘要:本研究基于CMIP6模式的Historical和SSP2-4.5情景,探究了全球变暖背景下热带太平洋次表层温度的变化趋势。研究发现,在1950-2100年间热带太平洋近赤道区域两侧存在对称的次表层冷却趋势(2-8°N/S, 100-200 m)。冷却趋势主要由两个因素导致:温跃层的抬升(Thermocline Heaving)和涩度(Spiciness)的负趋势,即固定等密度面上温度的降低。这两个因素的贡献比例相当。一方面,南北太平洋近赤道风应力旋度出现显著变化趋势,引起埃克曼抽吸使温跃层抬升,导致下层冷水向次表层流动;另一方面,全球变暖背景下海水温度不断升高使露头线持续向极移动,高纬度较冷的海水通过潜沉作用直接到达副热带东部区域;此外,沿等密度面的异常平流作用也促进了海水降温。以上过程使南北太平洋副热带东部次表层的等密度面上产生显著的冷趋势,并沿地转流线传播到近赤道次表层海洋,进一步引起该区域的冷却。本研究主要强调了在全球变暖背景下涩度对次表层温度趋势预测的重要作用。

报告时间:2022年9月1日 09:30                                         
报告地点:2号楼1201
主持人:陈昇 助研,张涟漪 助研
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