Understanding the modes of the sea-ice thickness distribution: Processes and variability

了解海冰厚度分布的模式：过程和变化

• 批准号: 1203196
• 负责人: James Morison
• 金额: $ 24.42万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203196&HistoricalAwards=false
• 关键词: Understanding; modes; sea; ice; thickness

The sea-ice thickness distribution (ITD) is fundamental to understanding the heat, mass and freshwater budgets of the Arctic Ocean, plays important roles in climate feedbacks, and exerts strong control on regional primary productivity, marine navigation and surface operations. Estimates of ITD based on observations in the perennial ice zone (PIZ) nearly always exhibit a prominent mode at some thickness, hm, larger than and distinct from modal thicknesses associated with the annual freezeup and recently-opened leads. This mode has been interpreted as un-deformed multi-year ice at, or growing thermodynamically towards, its equilibrium thickness. Observations indicate significant inter-regional, annual and inter-annual variations of hm within the PIZ, over the approximate range 1 to 5 meters. This statistic of the ITD has received much less attention than other parameters, such as the mean, standard deviation and e-folding length scale of ridged ice. The results of this project will improve understanding of the variations in space and time of this ecologically and societally important measure of ice thickness.The PI hypothesizes that measurements of ice of near-modal thickness have reduced bias and random error with respect to other measures of ice thickness, thus making the mode a robust parameter of the ITD. The goal of the proposed research is to enhance understanding of the ITD, focusing on the mode hm, by producing improved estimates of space/ time variations of the ITD, and greater understanding of its role in Arctic climate. Specific objectives are (a) to test the hypothesis that the mode is robust to observational errors; (b) to document space and time variation of hm and other parameters of the ITD in the PIZ; (c) to simulate the variations of the ITD and hm as a response to prescribed forcing and compare results with observations; (d) to study the dependence of simulated ITDs on the formulation of ridging and on errors in the forcing data; and (e) to synthesize the results as a new analysis and interpretation of the ITD emphasizing hm and its variations. The study domain is the Arctic Ocean PIZ during the period 1975-2010. The timescales to be considered include inter-seasonal, inter-annual and trends, as well as physical processes acting on hours and longer.

海冰厚度分布（ITD）是了解北冰洋热量、质量和淡水收支的基础，在气候反馈中起着重要作用，并对区域初级生产力、海洋航行和水面作业施加强有力的控制。ITD的估计的基础上，在常年冰区（PIZ）的观测几乎总是表现出突出的模式在一定的厚度，hm，大于和不同的模态厚度与年度冻结和最近打开的引线。 这种模式已被解释为未变形的多年冰，或不断增长的，其平衡厚度。观测结果表明，在PIZ内，hm在大约1至5米的范围内存在显著的区域间、年度和年际变化。ITD的这一统计数据受到的关注远远低于其他参数，如脊冰的平均值、标准差和e-折叠长度尺度。该项目的结果将提高对这一具有生态和社会重要意义的冰厚测量的空间和时间变化的理解。PI假设，与其他冰厚测量相比，近模态冰厚的测量减少了偏差和随机误差，从而使模态成为ITD的一个鲁棒参数。拟议研究的目标是通过改进ITD空间/时间变化的估计，并更好地了解其在北极气候中的作用，以加强对ITD的理解，重点是模式hm。具体目标是：（a）检验该模式对观测误差具有鲁棒性的假设;（B）记录PIZ中hm和ITD其他参数的空间和时间变化;（c）模拟ITD和hm的变化，作为对规定强迫的响应，并将结果与观测结果进行比较;（d）研究模拟的ITD对脊形公式和强迫数据误差的依赖性;（e）综合结果，作为对ITD的新分析和解释，强调hm及其变化。研究领域是1975-2010年期间北冰洋PIZ。要考虑的时间尺度包括季节间、年际和趋势，以及作用于小时和更长时间的物理过程。