Geothermal heat flux is the dominant source of uncertainty in englacial-temperature-based dating of ice rise formation

Author:

Montelli Aleksandr,Kingslake JonathanORCID

Abstract

Abstract. Ice rises are areas of locally grounded, slow-moving ice adjacent to floating ice shelves. Temperature profiles measured through ice rises contain information regarding changes to their dynamic evolution and external forcings, such as past surface temperatures, past accumulation rates and geothermal heat flux. While previous work has used borehole temperature–depth measurements to infer one or two such parameters, there has been no systematic investigation of parameter sensitivity to the interplay of multiple external forcings and dynamic changes. A one-dimensional vertical heat flow forward model developed here examines how changing forcings affect temperature profiles. Further, using both synthetic data and previous measurements from the Crary Ice Rise in Antarctica, we use our model in a Markov chain Monte Carlo inversion to demonstrate that this method has potential as a useful dating technique that can be implemented at ice rises across Antarctica. However, we also highlight the non-uniqueness of previous ice rise formation dating based on temperature profiles, showing that using nominal values for forcing parameters, without taking into account their realistic uncertainties, can lead to underestimation of dating uncertainty. In particular, geothermal heat flux represents the dominant source of uncertainty in ice rise age estimation. For instance, in Crary Ice Rise higher heat flux values (i.e. about 90 mW m−2) yield grounding timing of 1400 ± 800 years, whereas lower heat flux of around 60 mW m−2 implies earlier ice rise formation and lower uncertainties in the ice rise age estimations (500 ± 250 years). We discuss the utility of this method in choosing future ice drilling sites and conclude that integrating this technique with other indirect dating methods can provide useful constraints on past forcings and changing boundary conditions from in situ temperature–depth measurements.

Publisher

Copernicus GmbH

Subject

Earth-Surface Processes,Water Science and Technology

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3