Collaborative Research: On the importance of Submesoscale processes for ocean productivity

合作研究：论次尺度过程对海洋生产力的重要性

• 批准号: 0928138
• 负责人: Amit Tandon
• 金额: $ 32.84万
• 依托单位: University of Massachusetts, Dartmouth
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0928138&HistoricalAwards=false
• 关键词: Collaborative; Research; importance; Submesoscale; processes

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). A hierarchy of numerical modeling studies will be performed to examine the processes by which nutrients are advected into the euphotic surface layer of the ocean to support phytoplankton productivity in pelagic regions with shallow pcynoclines. The model experiments are designed to test two competing hypotheses (i) that nutrients are upwelled by mesoscale eddies through eddy-pumping and eddy/wind interaction, vs. (ii) that the ageostrophic vertical motions supported by submesoscale (110 km scale, and O(1) Rossby number) frontal processes are largely responsible for the vertical nutrient fluxes. This proposal aims to extend the newly emerging understanding of submesoscale processes in the upper ocean to exploring their impact on biogeochemical transport and ocean productivity. Intellectual Merit Biogeochemical property fluxes (i.e. the transport of reactive tracers) are affected not only by physics, but also by biological reactions (sources and sinks for the tracers). This project will couple simple biological models with physical models ranging in complexity from the fully nonhydrostatic, three-dimensional (PE) model to the surface-quasigeostrophic (SQG) and semigeostrophic (SG) inversions, to gauge the effects of physical processes on biological productivity. To better understand the contribution of meso- and submeso-scale physics, the team will model both scales simultaneously, delineate between Ro1 (mesoscale) and Ro=O(1)(submesoscale) processes, and ascribe the vertical transport of phytoplankton nutrient to specific scales and processes under various physical scenarios. The pathways of water parcels will be analyzed in conjunction with physical and biological properties (vorticity, velocity, density, nutrient, and light) to gain a Lagrangian view of physical and biological coupling at meso- and submeso-scales. The focus will be on three important sets of questions. (1) What is the contribution of submesoscale processes to vertical nutrient transport in comparison to mesoscale processes? Which physical time scales (meso- or submeso-scale) are most commensurate with the biology and enhance the efficacy of nutrient transport? (2) What is the structure of the vertical velocity associated with different processes and scales? How is this affected by lateral density gradients, mixed layer depth, pycnocline stratification, and surface forcing? (3) How well do the SQG (and the SG and QG) inversions represent the submesoscale vertical velocity structure and transport? Broader Impacts Vertical transport between the pycnocline and surface mixed layer of the ocean is of importance in several biogeocehemical and physical contexts. Hence this study has broad implications. Coupling of biology to physics at submesoscales is relatively unexplored. The findings will help interpret biological observations and determine if indeed 110 km scale physics is relevant for productivity in carbon cycle models. The PIs will link this modeling and analysis work to observations by collaboration with a Japanese group making measurements in the Kuroshio, Norwegian group attempting to interpret high resolution satellite measurements, and an ONR-funded tracer release study of submesoscale lateral mixing. The project will support two postdoctoral researchers who will be trained in modeling and analysis, publication and presentation of results, and collaborative planning activities. The PIs will participate in education and outreach activities through the Ocean Explorium at New Bedford and the Summer Pathways program at Boston University. Women scientists will play an important role in this project and will serve as role models in research and outreach.

该奖项根据 2009 年《美国复苏和再投资法案》（公法 111-5）提供资金。将进行一系列数值模拟研究，以检查养分平流进入海洋透光表层的过程，以支持具有浅层青斜层的中上层区域的浮游植物生产力。模型实验旨在测试两个相互竞争的假设（i）营养物质通过涡流泵送和涡流/风相互作用被中尺度涡流上升，与（ii）亚中尺度（110公里尺度和O2）支持的地转垂直运动（1）罗斯比数）额叶过程主要负责垂直养分通量。该提案旨在扩展对上层海洋亚尺度过程的新认识，以探索其对生物地球化学传输和海洋生产力的影响。智力优点生物地球化学性质通量（即反应性示踪剂的传输）不仅受到物理影响，而且还受到生物反应（示踪剂的源和汇）的影响。该项目将把简单的生物模型与物理模型结合起来，其复杂程度从完全非静水三维（PE）模型到表面准地转（SQG）和半地转（SG）反演，以衡量物理过程对生物生产力的影响。为了更好地理解介观和亚介观尺度物理学的贡献，该团队将同时对这两个尺度进行建模，描绘Ro1（介观尺度）和Ro=O(1)（亚介观尺度）过程，并将浮游植物营养物的垂直运输归因于特定的各种物理场景下的规模和过程。水块的路径将结合物理和生物特性（涡度、速度、密度、营养物和光）进行分析，以获得介观和亚介观尺度物理和生物耦合的拉格朗日观点。重点将集中在三组重要的问题上。 (1) 与中尺度过程相比，亚中尺度过程对垂直养分输送的贡献是什么？哪些物理时间尺度（中观或亚中观尺度）与生物学最相称并增强养分运输的功效？ (2) 不同过程和尺度下垂直速度的结构是怎样的？横向密度梯度、混合层深度、密斜层结和表面强迫如何影响它？ (3) SQG（以及 SG 和 QG）反演能否很好地反映亚尺度垂直速度结构和输运？更广泛的影响 密斜层和海洋表面混合层之间的垂直输送在一些生物地球化学和物理背景中非常重要。因此，这项研究具有广泛的意义。亚介尺度下生物学与物理学的耦合相对尚未被探索。这些发现将有助于解释生物学观察结果，并确定 110 公里尺度的物理现象是否确实与碳循环模型中的生产力相关。 PI 将通过与在黑潮进行测量的日本小组、试图解释高分辨率卫星测量结果的挪威小组以及 ONR 资助的亚中尺度横向混合示踪剂释放研究合作，将这一建模和分析工作与观测结果联系起来。该项目将支持两名博士后研究人员，他们将接受建模和分析、结果出版和展示以及协作规划活动方面的培训。 PI 将通过新贝德福德的海洋探索馆和波士顿大学的暑期衔接项目参与教育和外展活动。女科学家将在该项目中发挥重要作用，并在研究和推广方面发挥榜样作用。