Real-time quality control of current velocity data on individual grid cells in WERA HF radar

Abstract

Ocean surface current data provided by shore-based High Frequency (HF) radar show sporadically non-realistic current vectors in some areas, particularly at the outer edges of the radar range. The present paper describes a quality control (QC) procedure which evaluates the data of an array-type HF radar system in near realtime and assigns a quality value on every single grid-cell measurement. The quality value can then be used to identify non-realistic measurements and remove them from the obtained current maps. This procedure was implemented on a pair of coastal radar systems of the University of South Florida during a measuring period of 9 months. It was observed that the method is very effective in removing occasional non-realistic measurements. In general, the WERA QC procedure has to be tuned to the specific local conditions of the system for optimal results and to have the right trade-off between correct outlier identification and false alarm rate according to the user requirements.