A novel algorithm for automatic tropical cyclone eye fix using Doppler radar data

Tropical cyclone (TC) is among the most destructive of weather phenomena. A key element in issuing early TC warnings is an accurate and timely knowledge of the location of the circulation centre, or ‘eye’, of the TC. However, TC radar eye fix is often carried out manually in practice, and results may vary among forecasters. In this paper, a novel motion field structure analysis method is described as an aid to locate TC eyes more accurately. The method is comprehensive, and can handle incomplete data and landfalling cases. Implemented on a standard desktop computer, an average error of 0.15 degrees in latitude/longitude on a Mercator Projection map for TCs that are completely inside the radar image is obtained. This is well within the relative errors given by different TC warning centres. The method provides an independent and objective source of information to assist forecasters to fix the TC centre.