Improving Sea-Breeze Forecasting through the Assimilation of Coastal Observations

Improving coastal forecasting is important for disaster preparedness, agriculture, the fishing industry, tourism, and wind and solar power production. The benefits of assimilating coastal observations from a moving platform were explored as a method to fill spatial gaps among 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 marine surfaces impacts coastal weather as a result of the formation of sea breezes, which are the primary source of summertime wind variability and are a challenge to forecast. Between 2011 and 2016, the Cape May-Lewes Ferry collected atmospheric and water quality data as it traversed the mouth of the Delaware Bay several times a day. New methods were developed to quality control and process the ferry data for use as forcing for several modeling sensitivity studies, along with observations from Delaware Environmental Observing System (DEOS). The Weather Research and Forecasting (WRF) model was carefully configured to include 15-sec MODIS data, 1-km G1SST SST data, and NAM 12-km forcing data, and then run on select case studies. The case studies were identified using synoptic typing and NEXRAD data to represent typical summertime conditions. Additional data from DEOS, Delaware Department of Transportation, New Jersey Mesonet, NOAA, and National Data Buoy Center (NDBC) were used to statistically validate the model in order to identify the best combination of data to force the model. We also examined the location and depth of the 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 quantified the onset, dissipation, and magnitude of sea breezes and assessed the benefits of assimilating terrestrial and coastal observations to study sea breeze. The results of this project will allow meteorologists to better forecast sea breezes, serve as a tool to study sea breeze-related convection, and guide to future modeling studies in coastal regions with complex coastlines.