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

• Main Authors: Hoppmann, Mario, Nicolaus, Marcel, Itkin, Polona, Cheng, Bin, Wilkinson, Jeremy P., Perovich, Donald K., Pedersen, Leif Toudal, Maksym, Ted, Tiemann, Louisa, Zhao, Jiechen, Sennechael, Nathalie
• Format: Conference Object
• Language: unknown
• Published: 2016
• Subjects: Antarctic; Arctic; Antarc*; Sea ice
• Online Access: https://epic.awi.de/id/eprint/42695/; https://epic.awi.de/id/eprint/42695/1/AGU_IMB_final.pdf; https://hdl.handle.net/10013/epic.49288; https://hdl.handle.net/10013/epic.49288.d001

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, this in-situ data is 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. We present results from an intercomparison study, which compares different techniques of IMB data processing, with a focus on the automatic calculation of sea ice thickness and snow depth in selected IMB datasets from the Arctic and Antarctic. The results of a number of existing algorithms are evaluated, and validated against reference datasets from manual inspection and co-deployed instruments. Finally, recommendations with respect to the manifold challenges of IMB data processing and -interpretation are highlighted.