Quality control for a network of SeaSonde HF radars

The proliferation of HF radar networks around the globe has made them a vital component of the ocean observing endeavor. There are approximately thirty-four nations with oceanographic HF radar networks, eight of which have over 10 radar stations in their network. Providing high quality measurements for sustained periods of time is of the utmost importance. The global HF radar network has been established to meet this goal. The network was established in 2012 with the goal of increasing the number of coastal radars, develop emerging applications of the data and to deliver a set of easy to use standard products. The network was established under the Group on Earth Observations (GEO) work plan for 2012-2015. The work plan endorses a task to plan a Global HF Radar Network for data sharing and data delivery and to promote the proliferation of HF radar surface current velocity measurements. The goal of this paper is to propose quality standards for this global network. In this paper we will take inventory of the existing quality assurance and quality control measures that have been proposed at the radial level and offer measures to manage the systems on a network level. We have developed a best practices checklist for validating and operating a HF radar stations in the Mid Atlantic - a checklist that can be transferred to other regions nationally and internationally. Some of these techniques include the comparison of radials from measured and ideal beam patterns. We have also performed beam pattern sensitivity tests, first order line settings tests, angular segmentation tests and different time averaging schemes on the radial data. We share the results of those tests here so that they may be replicated by other operators to strengthen the methodology. We propose best practices for the operation of a High Frequency radar network. The techniques outlined in this paper have shown an increased accuracy of the measured radial currents and a better understanding of the data processing stream associated with the particular HF radar system. The other networks around the globe can adopt the methods and best practices outlined in this paper. The other networks can also provide input to these methods and best practices which will result in an improved surface current measurement.