Improving Sea Breeze Forecasting through the Assimilation of Coastal Observations

Improving coastal forecasting in Southern Delaware is important for disaster preparedness, agriculture, the fishing industry, tourism, and wind and solar power production. The benefits of assimilating coastal observations from buoys and moving platforms are explored as a method to fill the spatial gaps between land-based observations. The marine atmosphere is less well observed than the terrestrial atmosphere, but is equally important in the development of sea breezes. The difference in heating, between terrestrial and coastal surfaces, can have a big impact on the weather as a result of the formation of sea breezes. This is important because sea breezes are the largest source of summertime wind variability and are a challenge to forecast. Since 2011, the Cape May-Lewes Ferry has been collecting atmospheric and water quality data as it traverses the mouth of the Delaware Bay several times a day. New methods were developed to quality control and process the ferry data so that they could be used as forcing data for several modeling sensitivity studies, along with observations from Delaware Environmental Observing System (DEOS) and National Data Buoy Center (NDBC). Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) Model simulations were run on select case studies identified using synoptic typing and NEXRAD data. The coupled and uncoupled model outputs, with and without the assimilation of coastal observations, were analyzed and compared against historical radar data and observations. We also examined the location of the boundary layer (sea breeze front) as it propagates inland, and the changes in wind speed, wind direction, temperature, and relative humidity once the front passes over a particular location. We were able to quantify the onset, dissipation, and magnitude of sea breezes and assess the benefits of using coupled modeling, forcing both terrestrial and coastal observations, to study sea breeze. The results of this project will allow meteorologists to better-forecast sea breezes and serve as a tool to study sea breeze convection.