Ship tracking for MOSAiC expedition

CGD Extremes is an activity whose goal is to bring together people from different sections in CGD to work on interdisciplinary science around the topic of extremes. After forming in late 2018, in the first phase it has acted as a collaboration incubator under the question,

“How do climate states and extremes in the atmosphere, ocean, land surface, ice and biosphere interact?”

Below are examples of ongoing work within the CGD Extremes participants.

The largest polar expedition in history – the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC; - began in late September 2019. This expedition will spend a year trapped and drifting in sea ice, investigating the causes and consequences of diminished Arctic sea ice cover. Part of the expedition planning is to make sure that the ship drifts in ice that does not melt out – an increasingly challenging task as much of the Arctic has shifted from a regime in the 1980s of relatively old, thick, perennial sea ice to the current regime of relatively young, thin and seasonal sea ice.

As part of the MOSAiC planning effort, simulations from NCAR’s Community Earth System Model (CESM) Large Ensemble were used to examine sea ice conditions that could be encountered during the year-long free drifting field campaign along potential ice floe tracks. The aims of this work were to offer insight on the representativeness of MOSAiC observations given the range of possible climate conditions, and to provide guidance about what types of observations can best assist with climate model improvement. These experiments also provided information about possible extreme conditions that could be experienced during the campaign.

Unique ice floe tracks (grey) for satellite observations (a), Seasonal (b) and Perennial (c) CESM-LE ensembles
Figure: Unique ice floe tracks (grey) for satellite observations (a), Seasonal (b) and Perennial (c) CESM-LE ensembles. Representative tracks (coloured with corresponding months shown at far right) based on the individual tracks are overlain. Dashed lines indicate boundaries for the Transpolar Drift, North Pole, Russian, and Canadian sectors. The Russian exclusive economic zone (EEZ) is shown by red stipples.


  • DuVivier et al. (2019, in review at the Cryosphere). Going with the floe: tracking CESM Large Ensemble sea ice in the Arctic provides context for ship-based observations.