Factors Influencing Suspended Sediment Flux in the Upper Gulf of California

Alvarez, Luis G.; Jones, Sarah E.

doi:10.1006/ecss.2001.0873

Cited by 55 publications

(39 citation statements)

References 18 publications

(22 reference statements)

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“…The heat and salt budgets suggest that the gravity currents play an important role in the flushing of the UGC. Although the largest resuspension of sediments in the UGC occur during spring tides, significant near-bottom suspended sediment fluxes out of the UGC occur only during neap tides, driven by the gravity currents (Alvarez and Jones, 2002).…”

Section: The Upper Gulf Of Californiamentioning

confidence: 99%

An Overview of the Physical Oceanography of the Gulf of California

Lavín¹,

Marinone²

2003

Nonlinear Processes in Geophysical Fluid Dynamics

158

149

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Abstract. The Gulf of California (GC) presents several oceanographic features that make it unique among semienclosed seas of similar latitude and dimensions, the most important being strong tidal mixing, some of it close to deep stratification. Three-dimensional numerical model results suggest that tidal mixing may be more important than the thermohaline circulation in causing the long-term residual circulation, which consists of outflow in the upper 200 m and inflow below, plus a seasonally-reversing surface layer. The GC is an evaporative basin, but in the mean it gains heat through the surface. Lacking a sill at the point of connection with the Pacific Ocean (PO), the GC is constantly shaken by a wide spectrum of signals coming from the PO, including tides, subinertial trapped waves of various frequencies and El Niño. The seasonal dynamics and thermodynamics of the GC are dominated by the PO, not by local wind or buoyancy flux. Local processes are important at shorter time scales and in altering the thermohaline characteristics of the upper-layer waters. Tidal currents generate internal tides, packets of solitons, and sea surface temperature fronts from which jets may form. Coastal upwelling also seems to generate jets that separate from capes, especially on the mainland coast. The mesoscale off-shore circulation in the GC consists of a series of basin-wide geostrophic gyres that reach below 1000 m; their effect on the mean and seasonal circulation and thermodynamics of the GC remains to be studied. During summer, the currents in the mainland continental shelf are due to coastal trapped waves, while during winter they are wind-driven. The most important interannual anomalies in the GC are due to El Niño.

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Section: The Upper Gulf Of Californiamentioning

confidence: 99%

An Overview of the Physical Oceanography of the Gulf of California

Lavín¹,

Marinone²

2003

Nonlinear Processes in Geophysical Fluid Dynamics

158

149

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“…Predictions are derived by empirically relating device output (typically acoustic signal-to-noise ratio or return signal amplitude in counts or decibels) and the SSC of the water [37][38][39][40][41][42]. When an acoustic instrument is calibrated for a water system in which suspended sediment properties display little time dependence, no additional sensor is needed to measure the SSC.…”

Section: Instrumentation and Theoretical Backgroundmentioning

confidence: 99%

“…Several researchers have investigated the performance of acoustic Doppler current profilers for the prediction of SSC in various water environments, including coastal environments and rivers [32][33][34][35][36]. Predictions are derived by empirically relating device output (typically acoustic signal-to-noise ratio or return signal amplitude in counts or decibels) and the SSC of the water [37][38][39][40][41][42]. When an acoustic instrument is calibrated for a water system in which suspended sediment properties display little time dependence, no additional sensor is needed to measure the SSC.…”

Section: Introductionmentioning

confidence: 99%

Sediment Size Effects in Acoustic Doppler Velocimeter-Derived Estimates of Suspended Sediment Concentration

Öztürk

2017

Water

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Backscatter output from a 10 MHz acoustic Doppler velocimeter (ADV) was used to quantify suspended sediment concentrations in a laboratory setting using sand-sized particles. The experiments included (a) well-sorted sand samples ranging in size from 0.112 to 0.420 mm, obtained by the sieving of construction sand, (b) different, known mixtures of these well-sorted fractions, and (c) sieved natural beach sand with median sizes ranging from 0.112 to 0.325 mm. The tested concentrations ranged from 25 to 3000 mg·L −1 . The backscatter output was empirically related to concentration and sediment size, and when non-dimensionalized by acoustic wavelength, a dimensionless sediment size gradation coefficient. Size-dependent upper and lower bounds on measurable concentrations were also established empirically. The range of measurable conditions is broad enough to make the approach useful for sand sizes and concentrations commonly encountered in nature. A new method is proposed to determine concentrations in cases of mixed-size sediment suspensions when only calibration data for well-sorted constituent sands are available. This approach could potentially allow better estimates when the suspended load is derived from but is not fully representative of the bed material, and when the size characteristics of the suspended material are varying in time over the period of interest. Differences in results between the construction and beach sands suggest that sediment shape may also need to be considered, and point to the importance of calibrating to sediments encountered at the site of interest.

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“…Optical Backscatter Sensor-OBS) y acústicos (e.g. Acoustic Doppler Current Profiler-ADCP) para estimar la CSS (Holdaway et al, 1999;Alvarez & Jones, 2001;Tattersall et al, 2003;Kostaschuk et al, 2005;Dinehart & Burau, 2005;Fettweis et al, 2006;Merckelbach & Ridderinkhof, 2006). El OBS es un sensor óptico que mide turbidez y CSS, detectando la radiación infrarroja retrodispersada por las partículas en suspensión (Creed et al, 2001).…”

Section: Introductionunclassified

Medicion de la concentracion de sedimentos en suspension mediante dispositivos opticos y acusticos: aplicacion en sistemas tropicales (Delta del rio Mira, Colombia)

Restrepo¹,

Pierini

2012

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RESUMEN.En los últimos años, la utilización de dispositivos ópticos (e.g. Optical Backscatter Sensor, OBS) y acústicos (e.g. Acoustic Doppler Current Profiler-ADCP) ha permitido monitorear con mayor resolución la variabilidad temporal y espacial de la concentración de sedimentos en suspensión (CSS) en ambientes costeros y estuarinos. Sin embargo, la aplicación de estas técnicas en ambientes tropicales ha tenido un desarrollo incipiente. En el presente trabajo se implementó un procedimiento de calibración para un dispositivo OBS-3A, tomando como patrón de calibración sedimento seco y desagregado de la zona de estudio. Además, se presentan las correcciones a las que se debe someter la señal de respuesta del ADCP, debido a la dispersión geométrica, la atenuación del sonido por el agua y las partículas en suspensión, para que sea útil en la estimación de CSS. El ADCP y el OBS-3A se utilizaron para realizar mediciones de CSS en el sistema deltaico del río Mira (isla del Morro y desembocadura principal), ubicado sobre la costa del Pacífico colombiano, un ambiente costero tropical donde algunos factores oceanográficos y estuarinos son determinantes en la señal de respuesta de los equipos. Palabras clave: sedimento en suspensión, transporte de sedimento, instrumentos ópticos (OBS), equipo acústico (ADCP), deltas tropicales, Colombia. Measurement of suspended sediment concentration using optical and acoustic devices: application in tropical systems (Mira River Delta, Colombia)ABSTRACT. In recent years, the use of optical (Optical Backscatter Sensor, OBS) and acoustic (Acoustic Current Doppler Profiler, ADCP) instruments has allowed monitoring the temporal and spatial variation of the suspended sediment concentration (SSC) in coastal and estuarine environments with greater resolution. However, the development of the application of those techniques in tropical environments is incipient. For this study, an OBS-3A calibration procedure was implemented, taking dry and desegregated sediment from the study zone as a calibrating pattern. Moreover, we present the corrections required for the ADCP signal to be useful in the estimation of SSC due to geometrical spreading, the attenuation of sound by water, and the particles in suspension. The ADCP and OBS-3A were used to measure SSC in the Mira River delta system (Morro Island and principal river mouth), located on the Pacific coast of Colombia, a coastal tropical environment where some oceanographic and estuarine factors determine the signal response of the instruments.

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Factors Influencing Suspended Sediment Flux in the Upper Gulf of California

Cited by 55 publications

References 18 publications

An Overview of the Physical Oceanography of the Gulf of California

An Overview of the Physical Oceanography of the Gulf of California

Sediment Size Effects in Acoustic Doppler Velocimeter-Derived Estimates of Suspended Sediment Concentration

Medicion de la concentracion de sedimentos en suspension mediante dispositivos opticos y acusticos: aplicacion en sistemas tropicales (Delta del rio Mira, Colombia)

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