Monitoring Arctic Polynyas from Space (MAPS)

The decline of the Arctic sea ice has made shipping via the faster and safer northern sea routes a possibility.

Thus far though, commercial marine traffic is only possible in Russian territorial waters under Russian icebreaker escort, in summer. The reason is that the sea ice cover there has become seasonal, and its absence can be predicted months ahead. We argue that another feature of the Arctic sea ice can be predicted and used for navigation: polynyas.

Polynyas are large areas where the sea ice opens or thins significantly in response to wind pushing it apart and/or oceanic heat melting the ice from below and/or warm air intrusions melting it from above.

Some Arctic polynyas open every year at the same location, while others have started appearing in the “last ice area”, the region north of Greenland that still has a permanent thick ice cover.

This team successfully demonstrated that in the Southern Ocean, polynyas can be predicted up to four months before they open, by identifying their climatic drivers; the same should be feasible in the Arctic.

For navigation, seasonal prediction of polynya opening is not enough: should a ship enter a polynya, it would need high spatial and temporal information of the polynya location, growth or movements.

This is not feasible with traditional polynya observation methods, but we believe that hourly or higher resolution can be reached by tracking the polynyas’ signature on the cloud cover instead.The overall objective of this project MAPS is to create the first seasonal forecasting system of sea ice tailored to Arctic polynyas, based on remotely-sensed observations of the drivers that control polynya openings, and to incrementally increase the resolution of that system to ultimately allow for near-real-time monitoring of polynyas via their effect on the atmosphere.

This project will be carried out by a PhD student under our supervision who will:Determine the location, frequency, and drivers of polynya openings several months ahead for the whole Arctic;After identifying all Arctic polynya occurrences since satellite observations began in the 1970s, we will determine the process(es) that lead to their opening as a function of the season, region where the polynya opens, and type of polynya (coastal or open ocean).Quantify the respective roles of dynamics and thermodynamics on day-to-day polynya changes;Focussing first on the recent winter polynyas, for which sea ice thickness products are available, we will determine to what extent sea ice growth or melt (thermodynamics) and sea ice displacement (dynamics) are responsible for daily polynya size, shape and location changes, and how predictable these are throughout the Arctic.

We will conduct a similar study in the "last ice area" summer polynyas, for which fewer remote sensing products are available but in which this team has collected in-situ observations.

Use the polynya-cloud interaction to enable high temporal resolution polynya monitoring.The thermodynamics effects of WP2 will also yield the heat and moisture fluxes emitted by the polynya, which we will use as inputs (along with atmospheric profiles) for very high-resolution large eddy simulations of the cloud cover resulting from polynyas.

We will try and track this cloud cover in weather satellites, to obtain hourly or higher information about the location and size of the polynya.

This is an ambitious project, which requires expertise in all components of the Arctic climate system and in all types of datasets.

This team is internationally established, having been working for years at the interface between remote sensing, in-situ observations, and modelling to investigate the complex ocean-sea ice-atmosphere interactions.

Along with our pedagogic and supervising experience, it makes us uniquely qualified to lead this project and guide a PhD student to the successful completion of their degree.