Observations of Ice-Ocean Momentum and Heat Fluxes at the SHEBA Ice-Camp

[9701797] Pinkel这个研究项目是一个大型的、协调的、多方参与的项目“北极海洋表面热收支”的关键组成部分。SHEBA项目将在一年的周期内同时测量大气、浮冰和上层海洋的各种通量和特性，这些通量和特性决定了北极海冰的总质量和能量预算。其目标是提高对冰雪覆盖的北冰洋如何以及在多大程度上影响低纬度地区和全球气候模式（GCMs）的气候变化的认识。为了实现这一目标，已经挑选出两个可能重要的辐射/气候反馈过程进行研究：冰反照率反馈和云辐射反馈。这一建议解决了SHEBA处理冰反照率反馈机制的海洋学部分。两台特别建造的声学多普勒电流分析器（ADCP）将被部署，以调查风和洋流在冰从一个地方移动到另一个地方的作用。一个深剖面系统包括一个140千赫，四波束编码脉冲声纳。这将以3米的空间分辨率剖面到400米。它将提供埃克曼层、深层混合层、中尺度和大尺度气流的准确图像。第二个是从冰面上部署的5波束560khz通量声纳，将提供对冰下边界层湍流动量通量的直接估计。当与温度和盐度的同时测量相结合时，也可以估计湍流热通量。目的是在示巴营地的整个12-13个月期间运行这两个仪器。SHEBA的综合测量集将使北极地区的气候模型得以改进。这些改进的模型将有助于更好地预测气候和北极冰盖的持久性，因为如果大气中的二氧化碳含量高于目前的水平，就可能发生全球变暖。

9701797 Pinkel This research project is a key component of a large, coordinated, multi-investigator program called SHEBA (Surface Heat Budget of the Arctic) Ocean. The SHEBA program will simultaneously measure, over an annual cycle, the various fluxes and properties of the atmosphere, ice pack, and upper ocean that determine the aggregate mass and energy budgets of Arctic sea ice. Its goal is improved understanding of how and to what extent, the ice covered Arctic Ocean affects climate variability in lower latitudes and in global climate models (GCMs). Towards that goal, two potentially important radiation/climate feedback processes have been singled out for study: Ice-Albedo Feedback and Cloud-Radiation Feedback. This proposal addresses an oceanographic component of SHEBA dealing with ice-albedo feedback mechanisms. Two specially constructed acoustic Doppler current profilers (ADCP)s will be deployed to investigate the roles of wind and ocean currents in moving ice from place to place. A Deep Profiling System consists of a 140 kHz, four beam coded pulse sonar. This will profile to 400 m with 3 m spatial resolution. It will provide an accurate picture of the Ekman layer, the deep mixed layer, meso and large scale flows. A second, five beam 560 kHz Flux Sonar deployed from the ice, will provide direct estimates of the turbulent momentum flux in the under-ice boundary layer. When coupled with co-located measurements of temperature and salinity, turbulent heat fluxes can be estimated as well. The intention is to run these two instruments for the full 12-13 month duration of the SHEBA camp. The combined set of measurements in SHEBA will allow refinement of climate models for the Arctic region. Those improved models will lead to better predictions of the climate and the permanence of the Arctic ice cap under a proposed global warming that could occur if atmospheric carbon dioxide levels are increased above present levels.