Beaufort/Chukchi Seas mesoscale meteorology modeling study

Ongoing oil development in the Beaufort/Chukchi Seas is accompanied by the potential threat of oil spills. As recent events in the Gulf of Mexico have unfortunately demonstrated, such spills can have an extraordinary impact on sensitive ecosystems in the surrounding regions, but their movement and transport is often frustratingly unpredictable. In the event of such a spill, time is of the essence in directing mitigation, cleanup, and recovery efforts, and thus improving the predictability of oil spill transport is of great importance to all concerned. As the surface wind field is the primary factor in driving ocean currents, and thus the dispersal of any accompanying oil, accurate modeling of the region's surface winds is essential in enhancing the prediction of oil spill transport. As such, an environmental study of the mesoscale meteorology of the Beaufort/Chukchi region has been commissioned by BOEMRE in an effort to ensure the accurate simulation of near-surface winds, which will thereby lead to improved prediction of oil spill dispersal.

The Beaufort/Chukchi region represents a highly complex geographical environment that is understandably difficult to accurately model. It comprises highly varying topography, bounded in the south by the Brooks Range, and sea ice is a constantly changing presence in the ocean, experiencing seasonal growth, decay, and transport. In addition, due to its remote nature, observations are sparse throughout the area, further complicating efforts to accurately simulate mesoscale meteorology in the region. To address these challenges, a strategy was designed to conduct this study though the combined efforts of data collection and numerical modeling. An extensive data collection and quality control effort was organized, including the first-ever deployment of a stationary meteorological buoy in the Beaufort Sea. The Weather Research and Forecasting (WRF) model was used to produce numerical simulations of the Beaufort/Chukchi mesoscale meteorology at a grid spacing of 10 km. A thorough effort to test various model physics, analysis nudging, and data assimilation techniques was performed in an attempt to optimize the model configuration for use in the study area, including the coupling of a new thermodynamic sea ice model with WRF. Collected data have been used for both data assimilation and model verification. A 5-year (2005–9) experimental reanalysis simulation with the optimized model and assimilation configuration has been carried out, in preparation for the production of a final 31-year (1979–2009) reanalysis to be available for public distribution in 2012. The results of the experimental reanalysis demonstrate significant improvements in representing surface conditions relative to those produced by the “out of the box” WRF configuration.