Tide and wind forcing of estuarine upper water column turbulence

Abstract

Upper water column turbulence is often important to estuarine dynamics and constituent transport, yet our lack of comprehensive observations limits our understanding, and its prediction is a weakness of numerical models. Here, we describe observations of turbulence over a range of wind and tidal forcing in the Hudson River estuary and preliminary comparisons of the observations against a series of empirical and theoretical models of increasing complexity. A field experiment was conducted along a broad 5 m deep section of the Hudson over one month in fall, 2007. An autonomous instrumented catamaran was anchored near a bottom-mounted 1200 kHz acoustic Doppler current profiler that was measuring vertical profiles of velocity and several turbulence parameters using the variance method. The catamaran held an acoustic Doppler velocimeter, a sonic anemometer, an inertial sensor, and other instrumentation (e.g. carbon dioxide air-sea fluxes). Anchor stations (12-hour) and along- and across-channel transects were conducted from a small boat with CTD profiling to observe density stratification. Of particular interest are the effects of tidal currents and a superimposed along-estuary wind ......