Summary of the radial to total procedure:
The way the total vectors are computed is that all the radials currents which meet specific temporal and spatial thresholds are included in the calculation.
The temporal criteria: only radials from the center (current) time are used. That is no radial data before or after the center time are included.
The spatial criteria: at the location of each total current grid point a 3 km circle is placed in the radial maps. Any radials from any of the sites that fall within that circle are included in the total calculation.
Thresholding criteria (pre-calculation): Any radial currents > 150 cm/s are discarded before the total calculation. A minimum of 3 radial from at least 2 sites are required, otherwise no calculation is performed.
The procedure is to place all the radial estimates that meet the above temporal, spatial, and thresholding criteria in a matrix, and use a linear least squares matrix calculation to determine the total u/v currents.
Thresholding criteria (post-calculation): Any total currents with a speed > 100 cm/s or associated mapping error > 1.2
Low Pass Filter: Radially interpolated radial data are used to make totals. Total current time series are created for each grid point. Gaps of six hours or less are filled using linear interpolation. A 33-hour low pass filter was applied to data, which effectively removes all high frequency signals in the data, including the semi-diurnal and diurnal tidal currents.