现场粒径分析仪与ADCP同步测量悬浮沉积物浓度的粒径修正方法  

PARTICLE SIZE CORRECTION OF SUSPENDED SEDIMENT CONCENTRATION MEASURED BY ADCP WITH IN-SITU PARTICLE SIZE ANALYZER

作　　者：兰志刚[1] 龚德俊[1] 于新生[1] 李思忍[1] 徐永平[1] 

机构地区：[1]中国科学院海洋研究所,青岛266071

出　　处：《海洋与湖沼》2004年第5期385-392,共8页Oceanologia Et Limnologia Sinica

基　　金：中国科学院重大科技合作项目 ;H4 2 0 32 6 0 2号 ;中国科学院海洋研究所知识创新领域前沿项目 ;L84 0 32 6 0 9号 ;中国科学院留学基金项目 ;2 0 0 2- 2 0 0 3

摘　　要：利用后散射强度 (ABS)估计悬浮沉积物浓度原理 ,根据Rayleigh散射理论 ,给出了利用现场粒径分析仪与声学多普勒流速剖面仪 (ADCP)同步测量悬浮沉积物浓度的粒径修正方法 ,并推导出了一种新的、用于对ABS进行粒径修正的等效粒径计算公式 ( 9)。利用这一公式并结合LISST 1 0 0所测的粒径分布信息 ,可以对ADCP所测的ABS进行粒径修正 ,其修正方法见式 ( 1 0 )。结合利物浦湾和Anglesey周边海域的现场采样、测量及其分析结果 ,对上述粒径修正方法进行了验证。分析结果表明 ,采用上述公式进行粒径修正后 ,ADCP测量悬浮沉积物浓度的精度有较大程度的提高 ,线性拟合的相关系数从 0 .65— 0 .71提高到 0 .78— 0 .88。Measurements of suspended sediment load are crucial to the study of dynamics of suspended sediment. Over last decade, much work has been carried out in exploring the potential of ADCP (Acoustic Doppler Current Profiler) to estimate SSC (Suspended Sediment Concentration), due to its commercial availability and widespread application in measuring current velocity. One of the great advantages of the ADCP is its capability of measurement throughout the whole water column for a long period and the combination of measurements of vertical profiles of fluid velocities and back scatter intensities. This method not only improves temporal and spatial resolutions of SSC estimates, which are essential to the study of suspended sediment dynamics, but also can directly evaluate profiles of suspended sediment flux, and hence transport from just one instrument. Analysis of acoustic backscatter data with suspended sediment concentrations, however, must take account of the fact that ADCP observation may represent concurrent changes in concentration and morphology of suspended sediment without discrimination. Detailed knowledge of the characteristics of the suspended sediment, therefore, is essential for obtaining an accurate measurement. Variable nature of sound scatterers and some other physical parameters in ocean makes it difficult for in-situ estimation of all relevant parameters to inverse acoustic back scatter signals to accurate measurements of suspended sediment concentration with high resolution. Accurate measurements can’t be obtained without particle size correction due to particle size dependence of ABS (Acoustic Backscattering) measurement. Based on Rayleigh Scattering Theory, the equivalent particle radius as well as the calibration equation was derived for particle size correction of ABS. When the wavelength of incident sound is much greater than the diameter of scatters, Rayleigh scattering function applies, which means that the backscattering cross section is proportional to the fourth power of the scatter ra

关 键 词：ADCP 悬浮沉积物 粒径修正 后散射强度 

分 类 号：P736.21[天文地球—海洋地质]