Turbidity maximum formation in a well-mixed macrotidal estuary: The role of tidal pumping

Abstract

Traditionally, vertical circulation (induced by gravity circulation and tidal straining), tidal pumping, and resuspension are suggested as the major processes for the formation and maintenance of the estuarine turbidity maximum (ETM). Due to strong mixing, tidal pumping is considered as the dominating process in macrotidal estuaries. To analyze field observation data, the classical empirical decomposition method is commonly suggested, but the tidal pumping flux (TPF) based on this method may lead to erroneous conclusions about the mechanisms of ETM formation because the effects of advection induced by the horizontal SSC gradient and fine bed sediment supply are ignored. If these effects are included, the TPF clearly reproduces the convergence patterns and thus demonstrates its role in the formation of the ETM. By a simplified analytical solution, the TPF is the result of the competition between the downstream flux induced by the river current together with the lag in sediment response and the upstream flux induced by tidal asymmetry and the lag. Field observations in the well-mixed macrotidal Yalu River estuary (located between China and North Korea) were analyzed. Tidal pumping is identified as the dominant mechanism of its ETM formation, and the position of the ETM for different river discharges and sediment settling velocities can be predicted by the concept of tidal pumping by numerical and analytical procedures. The present study provides a typical example of how to evaluate the tidal pumping contributions on ETM formation using the combined information provided by field data, numerical modeling results, and analytical solutions.

Application of the Geostationary Ocean Color Imager to Mapping the Diurnal and Seasonal Variability of Surface Suspended Matter in a Macro-Tidal Estuary

“…The RMSE between in situ TSM and GOCI-retrieved TSM was 9.11 g¨m´3, which is reasonably good considering the comparison was not exactly synchronized. The GOCI results retrieved from this algorithm also agreed with other studies in the YRE and Yellow Sea based on in situ data and results retrieved from other ocean colour satellites [22,[41][42][43]. .…”

“…It originates in Changbai Mountain and has a total length of 790 km. The average annual discharge is about 2.5ˆ10 10 m 3¨y ear´1 (equating to 800 m 3¨s´1 ), and the average annual sediment load is 1.6ˆ10 6 t [22]. The Yalu River drainage has a mid-latitude, continental, monsoon climate; with an annual mean temperature of 8˝C and 881-1087 mm of rainfall per year.…”

“…2016, 8,244 3 of 20 the average annual sediment load is 1.6 × 10 6 t [22]. The Yalu River drainage has a mid-latitude, continental, monsoon climate; with an annual mean temperature of 8 °C and 881-1087 mm of rainfall per year.…”

Development and extension of an aggregated scale model: Part 2 — Extensions to ASMITA

“…The convergence of the two gives rise to a turbidity maximum at some points in the estuary depending on the relative strength of the two influences. The landward mechanism has been characterised as tidal pumping (Friedrichs et al, 1998;Scully and Friedrichs, 2007;Yu et al, 2014) and can be thought of as an upstream directed discharge and associated sediment flux. For a convergent channel, the equations of mass continuity, momentum and the advection-dispersion are solved to obtain the net sediment flux, which can be expressed as (Friedrichs et al, 1998): …”

Observation of an Estuarine Turbidity Maximum in the Highly Impacted Capibaribe Estuary, Brazil

“…The physics underlying the formation of the ETM has been studied using both analytical and numerical models (GEYER, 1993;JAY;MUSIAK, 1994;BURCHARD;BAUMERT, 1998;YU et al, 2014) in which the effect of gravitational circulation and tidal pumping is of primary importance, with a high degree of interaction between the flow and the bed. Most ETM have been reported in meso or macro-tidal estuaries.…”