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: 0928617
• 负责人: Mark Friedl
• 金额: --
• 依托单位: Trustees of Boston University
• 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=0928617&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 MeritBiogeochemical 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 sub-mesoscales.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 ImpactsVertical 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.

该奖项是根据2009年《美国复苏和再投资法》(公法111-5)资助的。将进行一系列数值模拟研究，以考察营养物质平流进入海洋真光表层的过程，以支持具有浅跃层的远洋区域的浮游植物生产力。模式试验的目的是检验两个相互竞争的假设：(1)营养盐通过涡流抽运和涡风相互作用被中尺度涡旋向上涌出；(2)由次中尺度(110公里尺度，O(1)Rossby数)锋面过程支持的非地转垂直运动是垂直营养盐通量的主要原因。这一提议旨在扩展对上层海洋次中尺度过程的新的理解，以探索它们对生物地球化学传输和海洋生产力的影响。智力价值生物地球化学通量(即反应性示踪剂的传输)不仅受到物理的影响，而且还受到生物反应(示踪剂的源和汇)的影响。这个项目将把简单的生物模型与复杂的物理模型结合起来，从完全非静力三维(PE)模型到表面准地转(SQG)和半地转(SG)逆过程，以衡量物理过程对生物生产力的影响。为了更好地理解中、亚中尺度物理的贡献，该团队将同时对两个尺度进行建模，描绘RO1(中尺度)和Ro=O(1)(亚中尺度)过程，并将浮游植物营养物质的垂直输送归因于不同物理情景下的特定尺度和过程。水团的路径将结合物理和生物特性(涡度、速度、密度、营养物质和光)进行分析，以获得中、亚中尺度物理和生物耦合的拉格朗日观点。重点将集中在三个重要的问题上。(1)与中尺度过程相比，次中尺度过程对垂直营养物质输送的贡献是什么？哪些物理时间尺度(中尺度或亚中尺度)与生物学最相称，并增强营养物质输送的有效性？(2)与不同过程和尺度相关的垂直速度的结构是什么？这是如何受到横向密度梯度、混合层深度、跃层层结和表面强迫的影响的？(3)SQG(以及SG和QG)反演对亚中尺度垂直速度结构和输送的表现如何？更广泛的影响在几个生物、海洋和物理背景下，海洋的跃层和表层混合层之间的垂直输送是重要的。因此，这项研究具有广泛的意义。在亚中间尺度上，生物学与物理学的耦合相对来说还没有被探索。这些发现将有助于解释生物学观察，并确定110公里尺度的物理是否确实与碳循环模型中的生产率有关。PIS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的挪威小组以及由ONR资助的亚中尺度横向混合的示踪剂释放研究合作，将这项模拟和分析工作与观测工作联系起来。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、成果的出版和介绍以及合作规划活动方面的培训。PI将通过新贝德福德的海洋探索中心和波士顿大学的夏季路径计划参与教育和外展活动。女科学家将在这一项目中发挥重要作用，并将在研究和推广方面发挥榜样作用。