Given the rapid changes in the polar regions, this session addresses key physical and chemical processes, especially in the boundary layer, over the Arctic and Antarctic whose understanding is needed to improve predictability of future changes in the polar regions. These processes include surface exchange of heat, momentum, moisture, and chemical constituents over increasingly complex ocean-ice-snow-land surfaces. Also of importance is dynamical connection of polar regions to the mid-latitudes for their supply of heat, moisture, and various chemical species. Of increasing interest is the role of extremes in the atmospheric circulation, particularly meridional transport events that can disturb the physical and chemical state of the high latitudes (that may be associated with rapid sea ice reduction, melting of the ice sheets, and marine physical and ecosystem changes, etc.).

This session is intended to provide an interdisciplinary forum to bring together researchers working in the areas of high-latitude weather and climate, boundary layer exchange processes, chemistry, and oceanography. We invite contributions in the following areas:

1. Observations and research that explore physical and chemical exchange processes over ocean-ice-snow-land surfaces in the polar latitudes ranging from molecular to regional scales.
2. Results from high-elevation sites where similar exchange processes over snow and ice are important are also welcome.
3. Results from field programs and observatories, insights from laboratory studies, and advances in modeling including parameterization of the boundary layer and reanalysis.
4. Advances in observing technology.
5. External controls on the boundary layer such as clouds, aerosols, radiation and transport processes.
6. The role of boundary layers in polar climate change and implications of climate change for surface exchange processes, especially in the context of reduced Arctic sea ice and physical and chemical changes associated with an increasing fraction of first year ice.