声学多普勒流速仪盲区数据处理及其在长江河口区的应用

Determination of current velocity in blank layer of ADCP

本文基于边界层理论,在估算声学多普勒流速仪(AcousticDopplerCurrentProfiler,简称ADCP)水表和底部的观测盲区流速作了初步探索。根据长江口南港定点观测获取的ADCP潮周期流速剖面数据的分析结果,在涨急和落急阶段整个水层均为边界层,流速剖面呈对数分布。因此,利用卡门-普朗特公式外插,计算ADCP盲区的流速,与在盲区放置的直读式流速仪测得的数据相比,平均相对误差分别为2 3%～2 9%。某些数据点的偏离可能是由于悬沙浓度分布的变化而引起的。

Based upon the boundary layer theory the method for determining the current velocity in the blank layer of ADCP (Acoustic Doppler Current Profiler) is proposed. It is assumed that the tidal flow during the ebb or flood maximum period is a boundary flow and the vertical velocity distribution follows the logarithmic law. Thus, the velocity in blank layer of ADCP can be determined by using extrapolation method based on the Karman-Prandtl equation for boundary layer flow. The comparison of the calculated velocity with measurement data by means of Valeport 106 current meter shows that the relative error is in the range of 2.3%-2.9%. Some deviations observed may be due to the variation of suspension distribution.