Storm Climate of the Western Arctic and its Impact on Shelf-Basin Exchange
Basic Project Information
It is predicted that one of the consequences of a warmer climate will be an increase in the intensity and frequency of cyclones that influence the arctic domain. This carries with it strong ramifications, including increased precipitation, more severe coastal flooding and erosion, and enhanced transfer of momentum to the pack-ice and the water beneath it. At present it is not well understood how such changing atmospheric conditions would influence the communication between the shelves and the interior Arctic Ocean. There is increasing evidence that wind-forcing is a dominant driver of such exchange, and that the impacts of this forcing involve multiple aspects of the food web. However, wind-forced shelf-basin exchange is not simply a regional phenomenon, but one that involves a mix of time and space scales, including understanding the behavior and evolution of storm systems centered thousands of kilometers away from the areas in question. In addition, the pack-ice significantly modulates the oceanic response. Therefore, it is necessary to address simultaneously different aspects the of the atmosphere-ice ocean system -over a myriad of scale- to understand fully the causes and effects of storm-driven shelf-basin exchange.
This project brings together multiple fields (meteorology, oceanography), disciplines (physics, biochemistry), and tools (atmospheric and oceanic modeling, data analysis) to enhance the understanding of the system-wide nature of wind-driven exchange and its impact on the ecosystem of the interior and coastal Arctic. The oceanic scope is the Chukchi/Beaufort Sea region, but the atmospheric connections extend into the North Pacific, which in this context clearly needs to be considered as part of the arctic system. The project will unfold in three phases. In phase I NCEP reanalysis fields, AMSR-E ice concentration data, and SBI mooring data will be used to investigate the present storm climate, elucidating the conditions (e.g. upper-level atmospheric currents, orography of Alaska, configuration of pack-ice) leading to the strongest upwelling and downwelling. In Phase II detailed case studies of three storm events will be performed using the MIT ocean/ice model, driven by output from the high-resolution WRF atmospheric model, and analyzed in tandem with the SBI physical mooring data and biochemical shipboard data. This will enable the understanding of how regional variations in the wind and ice fields, together with the topography, influence the shelf-basin exchange. Net fluxes of biochemically important properties for each of the storms will be computed, and scaled up to obtain annual fluxes. In Phase III automated cyclone tracking applied to the full NCEP data set, together with historical ice concentration data, will be used to investigate the storm climate and associated upwelling/downwelling over several decades that encompass different climatic regimes. This will allow an assessment of possible impacts of a future warmer climate.
This research will strive to determine what factors dictate the development and evolution of storms that lead to strong shelf-basin exchange, how the distribution of pack-ice modulates this, and the detailed dynamics that accomplish the exchange. Obtaining quantitative estimates of the associated biochemical fluxes will enable us to address the ramifications on the ecosystems of the shelves and central Arctic.
- Name: Michael Spall
- Department: Physical Oceanography
- Organization: Woods Hole Oceanographic Institution
- Email: mspall [at] whoi [dot] edu