ADCP回波信号在悬浮泥沙测量中的适应性研究

Studies on Adaptability of ADCP Echo Intensity to Suspended Sediment Measurement

选取福建省的湄洲湾、大港湾、东山湾外三个短期测站大、小潮观测数据为样本,利用ADCP现场测得的回波强度计算水体平均体积后散射强度,并建立其与悬浮泥沙浓度的回归关系。根据计算结果,受潮流、潮汐作用强烈的近岸海域,后散射强度与悬浮泥沙间具有良好的相关性,利用回归公式反演的悬沙浓度与实测数据平均相对误差均在20%以内,表明了此种方法在此类海区反演悬浮泥沙含量的可行性;对于随潮流、潮汐作用下悬浮泥沙浓度变化不强烈、水体混合均匀的海域,难以建立后散射强度与悬浮泥沙浓度的良好回归关系,不适宜用此类方法反演悬浮泥沙浓度。此外,为了得到波动范围更大的悬浮泥沙观测数据,应选取更能反映特定地点泥沙变化规律的时间段进行观测,选取的时间序列越长、越具有代表性,建立的回归关系越能反映悬浮泥沙输运特征。

Based on the observation data of three short-term stations in Meizhou Bay,Dagang Bay and outside Dongshan Bay in Fujian Province,the average volume backscatter intensity of water body was calculated by using the echo intensity measured with ADCP.The regression relationship between backscatter intensity and suspended sediment was established.According to the calculation results,The correlation between backscatter intensity and suspended sediment in the coastal waters was good although the tidal current and tidal action are strong in the coastal water.The average relative error between inverted suspended sediment concentration and measured data was less than 20%,indicating that this method of inverting suspended sediment content in such area is feasible.It was difficult to establish a good regression relationship between backscatter intensity and suspended sediment concentration in coastal waters not strongly influenced by tides and with uniformly mixed sediments.This method was not suitable for such coastal water.In addition,in order to obtain the observation data of suspended sediment whose fluctuation range was larger,the time period which can better reflect the variation of sediment should be selected for observation.The established regression relationship better refected the characteristics of suspended sediment transport,when longer and more representative time series were selected.