Characterizing the impact of underwater glider observations on the Navy Coastal Ocean Model (NCOM) in the Gulf Stream Region

• Main Author: Kausch, Kyle R.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 2021
• Subjects: Model; Glider; Gulf Stream; Eastman; North Atlantic
• Online Access: https://hdl.handle.net/1912/27438

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021. As the western boundary current of the North Atlantic, the Gulf Stream is a well established area of interest for the United States Navy, predominately due to its proximity to the continental shelf and the associated challenges of acoustic propagation across large property gradients. Autonomous underwater gliders conduct routine, high-resolution surveys along the U.S. East Coast, including within the Gulf Stream. These observations are assimilated into the operational Navy Coastal Ocean Model (NCOM). An investigation of the forecast-to-nowcast changes in the model for 2017 demonstrates the impact of the observations on the model. The magnitude of model change as a function of distance from nearest new observation reveals relatively large impact of glider observations within a radius of ????(100) km. Glider observations are associated with larger local impact than Argo data, likely due to glider sampling focusing on large spatial gradients. Due to the advective nature of the Gulf Stream system, the impact of glider observations in the model is anisotropic with larger impacts extending downstream from observation locations. Forecast-to-nowcast changes in modeled temperature, salinity, and density result in improved agreement between observed and modeled ocean structure within the upper 200 m over the 24 hours between successive model runs. This research was funded via the United States Navy’s Civilian Institution Program with the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program (MIT/WHOI JP). Glider observations and analyses have been generously supported by the National Science Foundation (OCE-0220769, OCE-1558521, OCE-1633911, OCE-1923362), NOAA’s Global Ocean Monitoring and Observing Program (NA14OAR4320158, NA19OAR4320074), the Office of Naval Research (N000141713040), Eastman ...