Accuracy and precision when deriving sea-ice thickness from thermistor strings: A comparison of methods

Richter, Maren E. ORCID: https://orcid.org/0000-0002-3658-3880, Leonard, Greg H., Smith, Inga J., Langhorne, Pat J., Mahoney, Andrew R. and Parry, Matthew (2023) Accuracy and precision when deriving sea-ice thickness from thermistor strings: A comparison of methods. Journal of Glaciology, 69 (276). pp. 879-898. ISSN 0022-1430

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Abstract

A precise knowledge of landfast sea-ice (fast-ice) thickness is relevant to many different disciplines. Sea Ice Monitoring Stations (SIMS) are used to measure time series of fast-ice thickness at a location. SIMS measure ice and ocean temperature via thermistor strings with many different methods for extracting sea-ice thickness from temperature existing. This study investigates: if thickness results from temperature recorded by SIMS of different designs, and analysed with different methods are comparable; which methods are recommended for their robustness, precision and accuracy and how they compare to independent thickness measurements; how otherwise unuseable data can be salvaged through specific SIMS designs. We present an analysis of fast-ice thickness calculated from SIMS deployed in McMurdo Sound, Antarctica and in the Chukchi Sea near Utqiaġvik, Alaska, over two decades. We find that median thicknesses derived by different methods agree within 1 ± 1.5 cm for McMurdo Sound and 2 ± 3 cm for Utqiaġvik. Thus, it is possible to confidently compare data collected from different stations and analysed with different methods. The vertical gradient of sea-ice temperature gives the best results for fast-ice thickness during the growth season and including standard resistors in a thermistor string can reduce potential data loss due to noise.

Item Type:	Article
Additional Information:	Acknowledgements: The code used to loess filter the input data was adapted from Peter Green's R code, which he wrote whilst employed at the University of Otago. Alex Gough's method of defining the ice–ocean interface from thermistor data was developed whilst he was supported by a University of Otago Doctoral Scholarship. MER was supported by a University of Otago Doctoral Scholarship and the 2019 Antarctica New Zealand Sir Robin Irvine Scholarship. MER is grateful to the Polar Environments Research Theme at the University of Otago and NZARI for conference funding. Thermistor data collected in McMurdo Sound between 1996 and 2003 are available under https://drive.google.com/drive/folders/1ooUH9dPvWT66afFC51Cb0JOHg66rn0sy , data collected in 2002 and 2003 were part of the project ‘Measurements and Improved Parameterization of the Thermal Conductivity and Heat Flow through First-Year Sea Ice’, OPP-0126007*. Data collected in 2009, 2010 and 2013 are available at the data repository PANGAEA (Gough and others, ; Smith and others, , ; Gough and others, ). The thermistor data in McMurdo Sound collected after 2009 were collected with the following funding and logistics support: IRL Subcontract to the University of Otago (2010, 2011); University of Otago Research Grants (2010, 2011, 2014, 2015 (Event Manager: Inga Smith)); NIWA subcontract to University of Otago, ‘Antarctic and High Latitude Climate’ (2013-2018); Contribution from MBIE-funded project ‘Antarctic sea ice thickness: harbinger of change in the Southern Ocean’ (2013 (PIs: Pat Langhorne and Wolfgang Rack)); Contribution from MBIE-funded Curious Minds public engagement project ‘Far from Frozen’ (2016, (leader: Craig Grant, Otago Museum)); US Fulbright Scholar Award (Cecilia Bitz, 2013); NZARI (2015 (PIs: Pat Langhorne and Craig Stevens), 2017, 2018 (PI: Greg Leonard)) Deep South National Science Challenge project TOPIMASI (2016–2018 (PI: Pat Langhorne)); Antarctic Science Platform Project 4 (Sea ice and carbon cycles) (2019, 2020 (Event Manager: Greg Leonard)); Marsden Fund project ‘Supercooling measurements under ice shelves’ (2020 (PI: Inga Smith)) and will be made available though PANGAEA. The thermistor data from the Arctic were collected as part of the Seasonal Ice Zone Observing Network (SIZONet) with funding from the National Science Foundation (OPP #0856867) and is available on the Arctic Data Centre under doi:10.18739/A2D08X (Eicken and others, ).
Uncontrolled Keywords:	glaciological instruments and methods,ice temperature,ice thickness measurements,sea ice,sea-ice growth and decay,glaciological instruments and methods,earth-surface processes ,/dk/atira/pure/subjectarea/asjc/1900/1904
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	01 Oct 2024 08:30
Last Modified:	19 Oct 2024 00:05
URI:	https://ueaeprints.uea.ac.uk/id/eprint/96844
DOI:	10.1017/jog.2022.108

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