基于ADP-XR和OBS-3A的潮滩水文泥沙过程研究 以胶州湾北部红岛潮滩为例

于2004年8月17~24日在胶州湾北部红岛潮滩上用OBS-3A和ADP-XR观测了水深、浊度、水平和垂直流速、回声强度、波浪、盐度、水温等水文泥沙要素,同时采集了悬沙和底沙样品作粒度分析.结果和结论为:(1)潮流动力较弱,表层和近底层最大流速分别只有31和26cm/s;(2)弱潮流动力导致潮周期大部分时间的悬沙浓度小于30mg/dm3,但浅水阶段近底悬沙浓度为100~1000mg/dm3;浅水阶段的短暂高悬浮泥沙浓度和其余长淹没时段的低悬沙浓度共同构成悬沙浓度的“U”形潮周期过程线;(3)悬沙浓度的垂直成层分布主要发生在潮周期的深水阶段和平静天气;(4)由于潮流弱和风浪的干扰,悬沙浓度未呈现大小潮周期的变化规律;(5)水体盐度为23.6~29.5;(6)淹没期的温度(21.4~28.6℃)比出露期的(19.3~30.9℃)稳定,温度极高值出现在午后出露期,而极低值出现在凌晨出露期;(7)“浅水效应”是弱动力潮滩泥沙运动的重要特点.

Observation of hydrographic and sedimentary processes over an intertidal flat based on ADP-XR and OBS-3A Taking Hongdao Island intertidal flat in the north of Jiaozhou Bay as an example

Turbidity,horizontal and vertical current speeds,echointensity,water depth,salinity and temperature were observed using OBS-3A and ADP-XR during a spring-neap period,on 17~24 August 2004.Meanwhile,suspended and bed sediments were sampled for grain size analysis.On the basis of calibration of turbidity with in situ sediment samples and regression between the turbidity and the echointensity,the turbidity and the echointensity were converted to a suspended sediment concentration (SSC).The SSC is found to be generally low.For most of the tidal duration,the near bottom(30 cm abovebed)SSC is less than 30 m g/dm³.Because mud grains are abundant in the bed sediments,the low SSC is mainly at tributed to low water energy especially weak currents.The near bottom current speed is generally less than 15 cm/s due to the narrow ness of the intertidal zone(500 m in width).However,the high SSC ranging f rom 100 mg/dm³ to greater than 1 000 mg/dm³ occurs during the shallow and short stages mainly due to the action of waves.As a result,the time series of near-bottom SSC is "U"-shaped during each tidal cycle.The vertical stratification of SSC tends to occurduring deep stages and calm weathers.The SSC does not show spring-neap cyclicity,which is at tributed to the int erference of waves.It is concluded that resuspension/settling over the study intertidal flat is governed by waves.