High-resolution investigation of sediment dynamics in the bottom boundary layer of a shallow,micro-tidal estuary
High-resolution data of current velocity and suspended sediment concentration (SSC) were collected using a pulse-coherent ADCP in the bottom boundary layer (BBL) of shallow Mobile Bay in the northern Gulf of Mexico.The data collected at two contrasting seasons were used to study the vertical and temporal variability in SSC under various forcing conditions.During the winter stormy season,the background SSC was low (15-30 g m-3).An episodic storm-induced erosion/resuspension was responsible for the short-lasting SSC peaks in BBL.During the spring flooding period,the background SSC was relatively high (40-70 g m-3) likely owing to the large fluvial input of suspended sediment and bed softening,and the contribution of wind forcing to sediment resuspension was somewhat enhanced by the destratification in BBL.When freshwater discharge was < 5000 m3 s-1,a critical wind stress for sediment erosion (0.08-0.1 Pa) was observed.When freshwater discharge was > 5000 m3 s-1,wind stress was no longer a main controller for SSC,showing a relatively poor correlation between the two.During the low-energy period with low freshwater discharge,the near-bed thermohaline density anomaly was a major factor that determined the stratification in BBL.Under very high freshwater discharges,the entire water column in shallow areas of the Bay was influenced by freshwater input.Then,the thermohaline anomaly’s contribution to the stratification considerably weakened while the SSC’s contribution strengthened.Despite a micro-tidal regime,Mobile Bay exhibited the cyclic erosion and deposition pattern induced by tidal acceleration and deceleration during tropic tides.
Suspended sediment concentration bottom boundary layer resuspension stratification Mobile Bay
Kyeong Park Ho Kyung Ha
University of South Alabama, Dauphin Island Sea Lab, Dauphin Island, Alabama, 36528, USA Korea Polar Research Institute, Korea Ocean Research and Development Institute, Inchon 460-840, Sout
国际会议
The 17th Pacific -Asian Marginal Seas Meeting(第十七届太平洋与亚洲边缘海国际会议)
杭州
英文
217-228
2013-04-23（万方平台首次上网日期，不代表论文的发表时间）