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首页> 外文期刊>Journal of oceanography >Correction method for full-depth current velocity with lowered acoustic Doppler current profiler (LADCP)
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Correction method for full-depth current velocity with lowered acoustic Doppler current profiler (LADCP)

机译：降低的声学多普勒电流剖面仪（LADCP）的全深度电流速度的校正方法

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A new method is presented to process and correct full-depth current velocity data obtained from a lowered acoustic Doppler current profiler (LADCP). The analysis shows that, except near the surface, the echo intensity of a reflected sound pulse is closely correlated with the magnitude of the difference in vertical shear of velocity between downcast and upcast, indicating an error in velocity shear. The present method features the use of echo intensity for the correction of velocity shear. The correction values are determined as to fit LADCP velocity to shipboard ADCP (SADCP) and LADCP bottom-tracked velocities. The method is as follows. Initially, a profile of velocity relative to the sea surface is obtained by integrating vertical shears of velocity after low-quality data are rejected. Second, the relative velocity is fitted to the velocity at 100–800 dbar measured by SADCP to obtain an “absolute” velocity profile. Third, the velocity shear is corrected using the relationship between the errors in velocity shears and echo intensity, in order to adjust the velocity at sea bottom to the bottom-tracked velocity measured by LADCP. Finally, the velocity profile is obtained from the SADCP-fitted velocity at depths less than 800 dbar and the corrected velocity shear at depths greater than 800 dbar. This method is valid for a full-depth LADCP cast throughout which the echo intensity is relatively high (greater than 75 dB in the present analysis). Although the processed velocity may include errors of 1–2 cm s?1, this method produced qualitatively good current structures in the Northeast Pacific Basin that were consistent with the deep current structures inferred from silicate distribution, and the averaged velocities were significantly different from those calculated by the Visbeck (2002) method.
机译：提出了一种新方法来处理和校正从降低的声学多普勒电流剖面仪（LADCP）获得的全深度电流速度数据。分析表明，除了在表面附近，反射声脉冲的回波强度与下倾和上倾之间的速度垂直切变差的大小密切相关，表明速度切变有误差。本方法的特征在于使用回波强度来校正速度剪切。确定校正值以使LADCP速度适合船上ADCP（SADCP）和LADCP底部跟踪的速度。方法如下。最初，在剔除低质量数据后，通过对速度的垂直切变积分来获得相对于海面的速度分布。第二，将相对速度拟合到SADCP测得的100–800 dbar的速度，以获得“绝对”速度曲线。第三，利用速度剪切误差与回波强度之间的关系来校正速度剪切，以便将海底速度调整为由LADCP测量的海底追踪速度。最后，从小于800 dbar的深度处的SADCP拟合速度和大于800 dbar的深度处的校正速度切变获得速度分布。此方法适用于回声强度相对较高（本分析中大于75 dB）的全深度LADCP转换。尽管处理后的速度可能包含1-2 cm s？1的误差，但该方法在东北太平洋盆地产生了质量上良好的海流结构，与由硅酸盐分布推断出的深海流结构一致，并且平均速度与那些速度有明显差异。通过Visbeck（2002）方法计算得出。

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