Use of GNSS-Derived PWV for Predicting the Path of Typhoon: Case Studies of Soulik and Kongrey in 2018

Abstract

The progress of a typhoon can be investigated by analyzing the significant changes in precipitable water vapor (PWV) in the area of interest. In this study, PWV variations of two typhoons in 2018 were investigated based on global navigation satellite system (GNSS)–derived PWV (GNSS-PWV) for predicting typhoon paths. In the study area, GNSS stations are densely distributed like an array so that the array enables the monitoring of the variations of PWV over the region more sensibly than a conventional PWV monitoring method, which consists of the radiosonde-based PWV observations (RS-PWV). To predict a typhoon’s subsequent location, the research proposes the concept of predicted location of typhoon (PLT). PLT is calculated as follows: (1)  all the GNSS-PWV in the study area during a typhoon event is estimated; (2) the top five GNSS stations showing the highest PWV are selected; (3) their two-dimensional (2D) mean position is calculated; and (4) this position indicates the PLT corresponding to the progress of the typhoon. The PLT was able to predict a typhoon’s subsequent location approximately 5 h in advance with an average distance discrepancy of 14 km. When the typhoon approached the landfall point, the PLT managed to predict the point approximately 5.3 h in advance, with an average distance discrepancy from the actual path of 13.19 km. These results imply that GNSS-PWV is promising for the prediction of the typhoon path, and it can be used as supplementary information for the current typhoon forecast.