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.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。一个层次的数值模拟研究将进行检查的过程中，营养物质平流到真光表层的海洋，以支持浮游植物生产力在远洋区浅pcypholine线。模式试验的目的是检验两个相互竞争的假设：（i）中尺度涡旋通过涡泵和涡/风相互作用使营养盐上涌;（ii）亚中尺度（110 km尺度，O（1）Rossby数）锋面过程支持的非地转垂直运动是营养盐垂直通量的主要原因。该提案旨在将新近出现的对上层海洋中尺度过程的理解扩展到探索其对海洋地球化学输送和海洋生产力的影响。生物地球化学性质通量（即反应性示踪剂的迁移）不仅受到物理学的影响，而且还受到生物反应（示踪剂的源和汇）的影响。该项目将简单的生物模型与复杂的物理模型相结合，从完全非流体静力学的三维（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。为了更好地理解中尺度和亚中尺度物理学的贡献，研究小组将同时对两个尺度进行建模，在Ro 1（中尺度）和Ro=O（1）（亚中尺度）过程之间进行划分，并将浮游植物营养盐的垂直输送归因于各种物理情景下的特定尺度和过程。将结合物理和生物特性（涡度，速度，密度，营养物质和光）分析水包裹的路径，以获得中尺度和亚中尺度物理和生物耦合的拉格朗日视图。重点将放在三组重要问题上。(1)与中尺度过程相比，次中尺度过程对营养盐垂直输送的贡献是什么？哪些物理时间尺度（中尺度或次中尺度）最符合生物学并能提高养分输送的效力？(2)与不同过程和尺度相关的垂直速度结构是什么？横向密度梯度、混合层深度、密度跃层分层和地面强迫是如何影响这一现象的？(3)SQG（以及SG和QG）反演对次中尺度垂直速度结构和输送的代表性如何？海洋密度跃层和表面混合层之间的垂直输运在若干海洋化学和物理背景下具有重要意义。因此，这项研究具有广泛的意义。在亚中观尺度上，生物学与物理学的耦合是相对未被探索的。这些发现将有助于解释生物学观测，并确定110公里尺度的物理学是否与碳循环模型中的生产力相关。PI将通过与一个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ONR资助的次中尺度横向混合示踪剂释放研究合作，将这种建模和分析工作与观测联系起来。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，结果出版和演示以及协作规划活动的培训。PI将通过新贝德福德的海洋探索和波士顿大学的夏季途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，并将成为研究和外联工作的榜样。