Remote sensing of atmospheric water vapor variation from GPS measurements during a severe weather event

The Global Positioning System (GPS) provides a relatively inexpensive method to remotely sense atmospheric water vapor in all weather conditions. In this study, we applied the GPS meteorology technique to monitor the precipitable water vapor (PWV) variation during a severe weather event (typhoon EWINIAR). The Korean weighted mean temperature equation (KWMTE), customized for the Korean Peninsula, was used to improve the accuracy of the GPS PWV estimation. The time series and the comparison with the images of MTSAT/CMAX and the GPS PWV contour maps indicated that the temporal change of GPS PWV was closely related to the progress of the typhoon. The correlation between the maximum GPS PWV and the maximum rainfall caused by the typhoon was also higher than that for the quiet weather period. Furthermore, the peak in the time series of GPS PWV was generally in good agreement with the time when the maximum rainfall was recorded. Our results therefore confirm that GPS meteorology is an efficient PWV sensing technique, capable of capturing the complex characteristics of water vapor distribution and its temporal variation during a period of severe weather events.