TY - JOUR
T1 - Tidal and atmospheric influences on near-surface turbulence in an estuary
AU - Orton, Philip M.
AU - Zappa, Christopher J.
AU - McGillis, Wade R.
PY - 2010
Y1 - 2010
N2 - Estuarine near-surface turbulence is important for transport, mixing, and air-water exchanges of many important constituents but has rarely been studied in detail. Here, we analyze a unique set of estuarine observations of in situ atmospheric and full water column measurements, estimated air-sea exchanges, and acoustic measurements of several terms in the turbulent kinetic energy (TKE) budget. Observations from a 5.1 m deep site in the Hudson River estuary include dissipation at 50 cm depth (ε50), as well as profiles of TKE, shear production of TKE (P), and net turbulent vertical TKE transport (T D). Regressions suggest that the principal controlling factor for ε50 was wind (through the surface shear velocity, U *) and that the surface heat flux and tidal currents played a secondary role. For ebb spring tides, the TKE budget at 50 cm depth was closed within noise levels. Ebbs had high ε50 due to local shear production, which nearly balanced ε50. Floods had TD approaching P in the upper water column but generally weak near-surface shear and turbulence. Examining buoyancy fluxes that impact near-surface stratification and can indirectly control turbulence, solar heat input and tidal straining caused similar buoyancy fluxes on a sunny, calm weather day, promoting ebb tide restratification. Wind-driven mixing was found to dominate during a fall season storm event, and strong overnight heat loss after the storm helped delay restratification afterward. These results demonstrate the utility of combining detailed air-sea interaction and physical oceanographic measurements in future estuary studies.
AB - Estuarine near-surface turbulence is important for transport, mixing, and air-water exchanges of many important constituents but has rarely been studied in detail. Here, we analyze a unique set of estuarine observations of in situ atmospheric and full water column measurements, estimated air-sea exchanges, and acoustic measurements of several terms in the turbulent kinetic energy (TKE) budget. Observations from a 5.1 m deep site in the Hudson River estuary include dissipation at 50 cm depth (ε50), as well as profiles of TKE, shear production of TKE (P), and net turbulent vertical TKE transport (T D). Regressions suggest that the principal controlling factor for ε50 was wind (through the surface shear velocity, U *) and that the surface heat flux and tidal currents played a secondary role. For ebb spring tides, the TKE budget at 50 cm depth was closed within noise levels. Ebbs had high ε50 due to local shear production, which nearly balanced ε50. Floods had TD approaching P in the upper water column but generally weak near-surface shear and turbulence. Examining buoyancy fluxes that impact near-surface stratification and can indirectly control turbulence, solar heat input and tidal straining caused similar buoyancy fluxes on a sunny, calm weather day, promoting ebb tide restratification. Wind-driven mixing was found to dominate during a fall season storm event, and strong overnight heat loss after the storm helped delay restratification afterward. These results demonstrate the utility of combining detailed air-sea interaction and physical oceanographic measurements in future estuary studies.
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U2 - 10.1029/2010JC006312
DO - 10.1029/2010JC006312
M3 - Article
AN - SCOPUS:78650257698
SN - 2169-9275
VL - 115
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
IS - 12
M1 - C12029
ER -