Measuring the melt rate of glacier ice with underwater noise

利用水下噪声测量冰川冰的融化速率

基本信息

批准号：
1748265
负责人：
Grant Deane
金额：
$ 29.99万
依托单位：
University of California-San Diego Scripps Inst of Oceanography
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-10-01 至 2020-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1748265&HistoricalAwards=false
关键词：
Measuring melt rate glacier ice

项目摘要

The development of a novel measurement of glacier ice melt rate is proposed using the underwater noise generated by bubbles bursting from the ice as it melts. The motivation for this work lies in the critical role melting plays in ice-ocean interactions in polar regions, and consequent sea level rise, combined with the great difficulty currently encountered when making direct or indirect measurements of ice melting. Glacier ice contains bubbles of air, trapped by falling snow and compressed over time by increasing pressure due to the accumulation of overlying ice. The explosive release of gas trapped within the bubbles as ice melts at the front of the glacier radiates an intense pulse of sound into the water, making glacial bays and fjords some of the noisiest places on the planet. Because bubble release rate increases with increasing ice melt rate, it should be possible to use bubble-generated noise to quantify melt rate. This project will contribute to STEM workforce development by providing support for the training of a post-doctoral associate. It will continue existing international collaborations with colleagues in Poland and Singapore. Outreach will occur through contributions to an innovative, planned exhibit at the Birch Aquarium ? Expedition Earth! Finally, a successful project will be an initial step in the development of a potentially transformative remote sensing technique for observing glacier-ocean interaction.This project will utilize a two-pronged effort to initiate development of an acoustic methodology for observing the melt rate of marine-terminating glaciers: direct measurement of the vertical distribution of noise sources on a terminus with a hydrophone array and recording the melting noise from large numbers of blocks of ice whose physical properties have been measured. An approach for the analytical analysis of the field measurements and initial development of an inversion technique is based on earlier work modeling noise radiated from bubbles in breaking waves. Data will be collected in front of a small group of glaciers terminating into a single fjord to address the following questions that presently limit the usefulness of acoustic data:1. What is the density, mean internal pressure and distributions of radii of bubbles in randomly selected samples of glacier ice, and how do these distributions correlate with ice density, which is a proxy for ice depth?2. How does the bubble source spectrum vary with hydrostatic pressure, bubble radius, internal gas pressure, and water temperature?3. What is the variability in the distributions of bubble properties between glaciers, and what are the minimal set of ice property measurements required to generalize the method from one to many glaciers? That is, what variables must be measured on a glacier-by-glacier basis to make the technique work across many glaciers?

使用冰层融化时的气泡产生的水下噪声提出了新型冰川冰熔体速率的新测量。这项工作的动机在于熔化在极地地区的冰山相互作用中的关键作用，以及随之而来的海平面上升，加上当前进行冰融化的直接或间接测量时目前遇到的巨大困难。冰川冰包含空气气泡，由于上覆冰的积累而增加压力，被降雪掉落并随着时间的推移压缩。随着冰川前部融化冰块的爆炸性释放，气泡被困在气泡中，散发出强烈的声音脉冲进入水中，使冰川湾和峡湾成为地球上一些最嘈杂的地方。由于气泡释放速率随着冰熔体速率的增加而增加，因此应该使用气泡生成的噪声来量化熔体速率。该项目将通过为培训后博士助理提供支持，从而为STEM劳动力发展做出贡献。它将继续与波兰和新加坡的同事进行现有的国际合作。外展将通过为桦木水族馆的创新，计划的展览做出贡献而发生？ Expedition Earth！最后，成功的项目将是开发一种潜在的变革性遥感技术来观察冰川 - 海洋相互作用的第一步。该项目将利用两种方便的努力来开发一种声学方法，以观察媒体终止冰川的融化速率的融合速率与近距离探索的噪声分布的噪声分布：测量物理特性的冰。对现场测量值的分析分析和反转技术的初始开发的方法是基于较早的工作模型，从而从破裂波中的气泡辐射出的噪声。数据将在一小部分冰川前终止于单个峡湾，以解决以下问题，这些问题目前限制了声学数据的有用性：1。在随机选择的冰川冰样品中，气泡半径的密度，平均内部压力和分布是什么？这些分布与冰密度如何相关，这是冰深的代理？2。气泡源光谱如何随静水压力，气泡半径，内部气压和水温而变化？3。冰川之间气泡特性的分布的变异性是什么？将方法从一种到许多冰川的概括所需的最小冰属性测量值是什么？也就是说，必须在冰川冰川基础上测量哪些变量以使该技术在许多冰川上起作用？

项目成果

期刊论文数量（3）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Vertical directionality and spatial coherence of the sound field in glacial bays in Hornsund Fjord

霍恩松峡湾冰川湾声场的垂直方向性和空间相干性

DOI：
10.1121/10.0002868
发表时间：
2020
期刊：
The Journal of the Acoustical Society of America
影响因子：
0
作者：
Vishnu, Hari;Deane, Grant B.;Chitre, Mandar;Glowacki, Oskar;Stokes, Dale;Moskalik, Mateusz
通讯作者：
Moskalik, Mateusz

Quantifying iceberg calving fluxes with underwater noise