A significant effort has been made by ACORN to assure quality of HF radar data going into the archive.  In developing QC indices for the WERA systems we found it necessary to revert to original Doppler Shift spectra coming from the WERA radars to set signal-to-noise limits and to remove outliers in determining surface current radial components.  ACORN have developed an analysis which uses near neighbour pixels, not to average or smooth, but to determine consistency of the data amongst noise and spikes.  In doing this he has produced for ACORN an improved analysis algorithm to step from raw spectra to surface current components.  This work has improved the capability of the WERA HF radar system for all users of the data.  The ACORN algorithm allows us to put meaningful Quality Control flags on the data points.  Some BEFORE and AFTER panels shown below illustrate the improvement in coverage and consistency using the ACORN algorithm compared with the basic WERA analysis.

Acknowlegdement and appreciation to Arnstein Prytz for his work on QC.

Below are 4 examples that illustrate the differences between the 2 QC routines; ACORN and WERA. All 4 examples are from the Tannum Sands radar station and radials produced from the ACORN routine are on the left while radials produced from the WERA routine are on the right. The uppermost 2 examples are from 16 June 2009 at 0200 GMT and are shown as example of when the differences between both routines is minimal -- i.e. signal to noise ratio of the sampled domain is relatively high. Whereas the example at the bottom, from 28 May 2009 at 2000 GMT shows a dramatic change between the 2 QC algorithms. The bottom example clearly shows the advantage of using the ACORN QC algorithm over that of the WERA.