Temporal variability of internal waves and vertical mixing in the North Atlantic

北大西洋内波和垂直混合的时间变化

基本信息

批准号：
257192667
负责人：
Dr. Janna Köhler
金额：
--
依托单位：
Institut für Umweltphysik (IUP)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/257192667?language=en
关键词：
Temporal variability internal waves vertical

项目摘要

The general objective of this project is the investigation of temporal variability in internal wave energy and the intensity of vertical mixing in relation to the North Atlantic Current and its eddy field. Thereby 5-6 year long observations from moored current meters and temperature/conductivity recorders from three moorings along a section west of the Mid-Atlantic Ridge as well as shipboard LADCP/CTD measurements will be used. Specific scientific goals are:- produce time series of internal wave energy from moored observation of currents and stratification - investigate time scales of variability in relation to wind input, position of NAC and eddies- identify generating processes of the observed variability, e.g. tides, storms, seasonal cycle, eddies, NAC branches (local/remote forcing)- determine variability of mixing (temperature inversions, Thorpe scales, finescale parameterization) in dependence on changing background propertiesTo achieve the above objectives, internal wave potential and kinetic energy spectra will be calculated and studied for their relation to variable background properties e.g. wind forcing, tides, passing eddies, stratification and variability in the NAC branches as well as for their dependence on the local MAR topography. Mooring instrumentation since summer 2012 additionally permits the calculation of internal wave vertical modes and energy fluxes which will yield information about the magnitude and temporal variability of energy transported by internal waves in the North Atlantic. Combining calculated energy fluxes with ray tracing methods for internal waves generated at the MAR will also enable the estimation of the relative importance of the MAR topography for the generation of internal waves in the study area. From summer 2015 onward analyses will be further extended by the calculation of time series of Thorpe scales and dissipation rates from temperature-pressure measurements. Results will be supplemented by the estimation of diapycnal diffusivities obtained from shipboard LADCP/CTD data from five cruises using a finescale parameterization. This allows the further analysis of dominant sources of internal waves and quantitative estimates of vertical mixing rates as well as their temporal and spatial variability

该项目的一般目标是研究内波能中时间变异性以及相对于北大西洋电流及其涡流的垂直混合强度。因此，将使用5 - 6年的观测值，从泊位的电流仪表和温度/电导率记录器沿着大西洋山脊以西的三个部分以及船上LADCP/CTD测量值的观察结果。特定的科学目标是： - 从系泊电流观察和分层的内部波能量的时间序列 - 研究与风输入相关的可变性时间尺度，NAC和EDDIE的位置 - 识别观察到的变异性的生成过程，例如潮汐，暴风雨，季节性周期，涡流，NAC分支（本地/远程强迫） - 确定混合的变异性（温度倒置，索普量表，罚款参数参数化）依赖于改变背景的属性实现上述目标，内部波电位和动能能量光谱将被计算并研究其与可变背景的关系。 NAC分支的风力强迫，潮汐，传递涡流，分层和可变性以及它们对当地MAR地形的依赖。自2012年夏季以来的系泊仪器还允许计算内波垂直模式和能量通量，这些模式和能量通量将获得有关北大西洋内波传输能量的幅度和时间变化的信息。将计算出的能量通量与在MAR生成的内部波的射线追踪方法相结合，还将能够估算MAR地形对于研究区域中内波的产生的相对重要性。从2015年夏季开始，通过计算索普量表的时间序列和耗散速率，将进一步扩展分析。结果将通过使用罚款参数化从五个巡航中的船板LADCP/CTD数据获得的二比纳尔扩散率估算来补充结果。这允许进一步分析内部波的主要来源以及垂直混合速率的定量估计以及它们的时间和空间变异性