currents in the practice of research are estimated on the basis of the satellite
altimetry data [9] using the data of current velocity at stations measured using
Lowered Acoustic Doppler Profiler (LADCP) [1, 2, 5, 6, 10, 11, 13] or by Shipboard Acoustic Doppler Current Profiler (SADCP) [12].
The estimation of the correctness of the absolute geostrophic current calculation
if the barotropic component determined on the basis of the ADCP data can be
divided into two tasks:
1. Estimation of the accuracy of the absolute geostrophic current approximation at
the segments of the section (survey) based on the measured profiles at the
stations corresponding to these segments.
2. Estimation of the distortion of the field of geostrophic currents associated with
the combination of non-stationarity of this field and non-simultaneity of the
measurements over a section (survey). This task can, in turn, be divided into
two more tasks:
2a. Estimation of the distortion of the baroclinic current component;
2b. Estimation of the distortion of the barotropic current component.
In this contribution, we will consider the latter of the above mentioned tasks
applied to particular hydrographic sections in relation to the barotropic component
of the current and the barotropic transport by the current. Here, we consider that the
measured current profiles accurately approximate the real geostrophic current with
respect to the determination of its barotropic component. We assume that the
current (its barotropic and baroclinic components) is considered as the normal
component of the actual current to the sections. In such a formulation of the task, its
solution does not require the involvement of field data in the entire ocean column,
but can be reduced to the investigation of the Sea Level Anomaly (SLA) at the
ocean surface, which is measured by modern satellite altimeters. Note that the
isolines of the level surface (absolute dynamic topography) determined by the first
term in Eq. (1a, 1b) represent the streamlines of the absolute geostrophic currents at
the ocean surface. The SLA at a particular location in the ocean is the instantaneous
deviation of the level from the mean value over the time period of observations.
The structure description of applied data is essential for the theoretical justification
of this study. Hence, first, we provide the information about these data (section “Data”), and then describe the method of the data analysis (section “Method of
Processing”). Section “Error Estimates” describes the error sources and gives quantitative estimates of the errors of calculations of the barotropic component of the
current and barotropic transport. In section “Discussion”, we analyze the results of
calculations performed according to the method described in section “Method of
Processing”. Section “Conclusions” summarizes the conclusions.
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R. Yu. Tarakanov
altimetry data [9] using the data of current velocity at stations measured using
Lowered Acoustic Doppler Profiler (LADCP) [1, 2, 5, 6, 10, 11, 13] or by Shipboard Acoustic Doppler Current Profiler (SADCP) [12].
The estimation of the correctness of the absolute geostrophic current calculation
if the barotropic component determined on the basis of the ADCP data can be
divided into two tasks:
1. Estimation of the accuracy of the absolute geostrophic current approximation at
the segments of the section (survey) based on the measured profiles at the
stations corresponding to these segments.
2. Estimation of the distortion of the field of geostrophic currents associated with
the combination of non-stationarity of this field and non-simultaneity of the
measurements over a section (survey). This task can, in turn, be divided into
two more tasks:
2a. Estimation of the distortion of the baroclinic current component;
2b. Estimation of the distortion of the barotropic current component.
In this contribution, we will consider the latter of the above mentioned tasks
applied to particular hydrographic sections in relation to the barotropic component
of the current and the barotropic transport by the current. Here, we consider that the
measured current profiles accurately approximate the real geostrophic current with
respect to the determination of its barotropic component. We assume that the
current (its barotropic and baroclinic components) is considered as the normal
component of the actual current to the sections. In such a formulation of the task, its
solution does not require the involvement of field data in the entire ocean column,
but can be reduced to the investigation of the Sea Level Anomaly (SLA) at the
ocean surface, which is measured by modern satellite altimeters. Note that the
isolines of the level surface (absolute dynamic topography) determined by the first
term in Eq. (1a, 1b) represent the streamlines of the absolute geostrophic currents at
the ocean surface. The SLA at a particular location in the ocean is the instantaneous
deviation of the level from the mean value over the time period of observations.
The structure description of applied data is essential for the theoretical justification
of this study. Hence, first, we provide the information about these data (section “Data”), and then describe the method of the data analysis (section “Method of
Processing”). Section “Error Estimates” describes the error sources and gives quantitative estimates of the errors of calculations of the barotropic component of the
current and barotropic transport. In section “Discussion”, we analyze the results of
calculations performed according to the method described in section “Method of
Processing”. Section “Conclusions” summarizes the conclusions.
362
R. Yu. Tarakanov