Onshore wind acceleration across the Indian River Lagoon
A study of the onshore (easterly) flow crossing the barrier island and Indian River Lagoon (IRL), in east central Florida, was conducted during the summer of 2015 in association with the DMES Field Projects. Wind observations were collected from three instruments including a vertically pointing lidar, a Kestrel sensor mounted at 10 m, and an AirMar sensor deployed (at 2 m) on a pontoon boat. The observations indicate that the downstream (IRL) wind speed (10 m) was actually higher than beachside. Surface roughness estimates are obtained from the lidar-observed wind profiles beachside and downwind along the western shore of the IRL. These roughness estimates were then used to calculate the 'potential wind’ at the IRL location. Results indicate that the over-water roughness differences, between the IRL and open ocean, are sufficient to explain most of the wind speed difference between locations. When compared to the ocean, the shallow estuary has limited fetch and lower roughness and thus the flow downstream of the barrier island accelerates to speeds in excess of those observed directly along the coast. The Weather Research and Forecasting (WRF) model was run in an attempt to simulate the observed flow. While the WRF captures the deceleration across the barrier island, it does not reproduce the full acceleration seen in the observations at the Lagoon House.