跨跃层和跨锋面的物质交换及其对东海缺氧演变的影响

Hypoxia in water, especially in coastal areas, has become one of the severe ecological environment problems in the world. Hypoxia is a typical international frontier research topic in the interdisciplinary fields of physical, chemical and biological oceanography, which is highly concerned by the ocean science community. Currently the relationship between hypoxia and its influencing factors has been widely studied and well understood. Because of the limitation of spatial and temporal resolution and coverage of the data, the study and understanding of the relationship between hypoxia and its influencing factors remain largely at the diagnostic level.The study and understanding of the evolutionary process of hypoxia is rare. The observed data show that the hypoxia in the East China Sea has multi-scale temporal variations, including the inter-annual, seasonal, synoptic and tidal cycles. The proposal intends to combine the means of satellite remote sensing, field observation and numerical simulation to overcome the limitation of spatial and temporal resolution and coverage of data. The study will focus on the material fluxes which determine the evolutionary process of hypoxia, namely the fluxes across pycnocline in the vertical direction and across front in the horizontal direction. The characteristics of the temporal and spatial variation and the associated mechanism will be explored for the hypoxia in the East China Sea. The study will promote the understanding of the relationship between hypoxia and influencing factors from diagnostic to prognostic levels. The gained knowledge will also provide a sound scientific basis to develop an ecosystem based management of the coastal waters.

水体缺氧尤其是近海海域缺氧已成为全球主要的生态环境问题之一。水体缺氧是典型的物理—化学—生物等多学科交叉的国际前沿研究课题，受海洋界的高度关注。目前对缺氧与影响因素之间关系已有广泛的研究和深入的认识，但是受资料时空分辨率低和覆盖范围小的制约，缺氧与影响因素之间关系的研究和认识仍偏重于某一时段的诊断关系上，缺少对其变化过程的研究和认识。观测资料显示，东海缺氧存在年际、季节、天气和潮周期等多种尺度的变化过程。本项目拟综合运用卫星遥感、现场观测和数值模拟的手段，突破资料时空分辨率低和覆盖范围小的限制，从影响缺氧变化的物质交换通量的角度出发，研究跨跃层和跨锋面的物质交换过程和机理，进而揭示东海缺氧的时空分布和变化过程的特征和规律，把缺氧与影响因素之间关系的认识从诊断关系水平提升到变化过程水平，为治理东海缺氧现象提供科学依据。

水体缺氧尤其是近海水体缺氧，已成为全球主要的生态环境问题之一。水体缺氧是典型的物理—化学—生物等多学科交叉的国际前沿研究课题，受海洋界的高度关注。目前对缺氧与影响因素之间关系已有广泛的研究和深入的认识，但是受资料时空分辨率低和覆盖范围小的制约，缺氧与影响因素之间关系的研究和认识仍偏重于某一时段的诊断关系上，缺少对其变化过程的研究和认识。项目通过综合运用卫星遥感、现场观测和数值模拟的手段，从不同侧面（海面、断面、剖面）突破资料时空分辨率低和覆盖范围小的限制，对缺氧演变过程及其机理开展多方位的研究。. 通过4年的研究，项目在遥感信息提取算法和分析方面，开展了多传感器海洋水色—水温遥感资料的锋面信息提取与分析、地球静止轨道和多源卫星融合资料的上升流信息提取和分析、卫星和现场观测资料融合的东海跨陆架营养盐通量的计算和分析等工作。在现场观测方面，开展了缺氧区锋面高分辨率AUV观测、缺氧区跃层高分辨率的浮标观测、缺氧区现场原位有机质耗氧速率的试验等方法研究和现场观测等工作。在数值模拟方面，一方面完善和发展海洋环流模式，以更好地模拟物理过程，并运用模拟结果研究了台湾暖流的时空变化、次中尺度过程对跃层内部影响等问题；另一方面完善和发展物理—生态耦合模式，重建东海缺氧的演变过程，揭示了底层水体缺氧与上层水体浮游植物水华之间的耦合和非耦合联系，提升了缺氧预报预警技术水平。. 项目利用遥感和现场观测资料，结合数值模拟，深入地分析研究了东海缺氧演变过程，尤其缺氧过程与物理—化学—生物过程、长江陆源和黑潮海源营养盐输入的关系，研究成果发表在J. Geophys. Res.，Prog. Oceanogr.，Limnol. Oceanogr.，Ocean Sci.，Front. Mar. Sci. 等国际著名海洋期刊上，提高了对物理—化学—生物耦合过程及其对缺氧演变定量贡献的认识，为东海缺氧灾害预报奠定了良好基础。. 项目已在国内外学术期刊上发表了24篇，申请和授权发明专利6项，培养博士研究生3名，硕士研究生3名。