A distributed network of temperature chains to autonomously monitor sea ice evolution on an ice floe during MOSAiC

Thermistor chains with the ability to record air, snow, ice and ocean temperatures are widely used on autonomous ice mass balance buoys (IMBs), which record the evolution of sea ice thickness and snow depth at a fixed site. The additional ability to actively heat their surrounding enables them to also determine sea ice thermal properties, as well as yielding more detailed information about surface and internal melt processes. In modern IMBs, these themistors chains are usually closely tied to a specific electronic setup, making it impossible to operate them independently. However, recent developments enable them to now be operated on any platform equipped with an RS232 interface. In combination with other improvements, such as increased resolution, sturdiness, and reliability, it is now the right time to look for applications beyond their use in (expensive) IMBs. Here we introduce the idea and concept to deploy a distributed network of such thermistor chains on the ice floe where RV Polarstern is anchored during the MOSAiC experiment. Powered by regular lead batteries and controlled by a cheap, commercially available microcontroller, the units will send their temperature and heating profiles in fixed intervals (e.g. 1 h) or on request to a central receiving unit on the ship via a direct communication link. Based on the incoming data in combination with high-resolution electromagnetic thickness surveys, a 3D temperature and thermal property map of the ice floe and the surrounding atmosphere and ocean is generated, which is then used to calculate sea ice thickness and snow depth in the covered area. Complementing regular sea ice thickness and snow depth surveys by other methods, this information is expected to be very valuable for many studies during MOSAiC

Per Anhalter durch die Polarmeere: Autonome und ferngesteuerte Technologien in der Meereisforschung

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Einsatz von autonomen und ferngesteuerten Technologien rund um das Meereis

Einsatz von autonomen und ferngesteuerten Technologien rund um das Meerei

Sea Ice Mass Balance Buoys (IMBs): Introduction to working group and Data Processing Intercomparison Study

IMBs are autonomous instruments able to continuously monitor the growth and melt of sea ice and its snow cover at a single point on an ice floe. Complementing field expeditions, remote sensing observations and modelling studies, these in-situ data are crucial to assess the mass balance and seasonal evolution of sea ice and snow in the polar oceans. Established subtypes of IMBs combine coarse-resolution temperature profiles through air, snow, ice and ocean with ultrasonic pingers to detect snow accumulation and ice thermodynamic growth. Recent technological advancements enable the use of high-resolution temperature chains, which are also able to identify the surrounding medium through a „heating cycle“. The temperature change during this heating cycle provides additional information on the internal properties and processes of the ice. However, a unified data processing technique to reliably and accurately determine sea ice thickness and snow depth from this kind of data is still missing, and an unambiguous interpretation remains a challenge. Following the need to improve techniques for remotely measuring sea ice mass balance, an international IMB working group has recently been established. The main goals are 1) to coordinate IMB deployments, 2) to enhance current IMB data processing and –interpretation techniques, and 3) to provide standardized IMB data products to a broader community. Here we present first results from two different data processing algorithms, applied to selected IMB datasets from the Arctic and Antarctic. Their performance with regard to sea ice thickness and snow depth retrieval is evaluated, and an uncertainty is determined. Although there are many challenges and caveats in IMB data processing and -interpretation techniques, such datasets bear great potential and yield plenty of useful information about sea ice properties and processes. It is planned to include many more algorithms from contributors within the working group, and we explicitly invite other interested scientists to join this promising effort

Sea ice mass balance buoys during MOSAiC in the context of long-term buoy data in the Transpolar Drift system

Presentation of SIMBA buoy ice & snow thickness retrievals (first preliminary version for Arctic PASSION) in relation to the MOSAiC drift experiment in 2019/2020. Part of the session on "MOSAiC Observations in the Context of Historical Data" during the 2nd MOSAiC Science conference in Boulder, Colorado, US (February 13-17, 2023)