GPS-based PWV for precipitation forecasting and its application to a typhoon event

• Published in: Journal of atmospheric and solar-terrestrial physics Vol. 167; pp. 124 - 133
• Main Authors: Zhao, Qingzhi, Yao, Yibin, Yao, Wanqiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2018
• Subjects: GNSS; Least-square fitting method; Precipitation forecasting; PWV; Precipitation forecasting; Least-square fitting method; GNSS; PWV
• ISSN: 1364-6826; 1879-1824
• DOI: 10.1016/j.jastp.2017.11.013

The temporal variability of precipitable water vapour (PWV) derived from Global Navigation Satellite System (GNSS) observations can be used to forecast precipitation events. A number of case studies of precipitation events have been analysed in Zhejiang Province, and a forecasting method for precipitation events was proposed. The PWV time series retrieved from the Global Positioning System (GPS) observations was processed by using a least-squares fitting method, so as to obtain the line tendency of ascents and descents over PWV. The increment of PWV for a short time (two to six hours) and PWV slope for a longer time (a few hours to more than ten hours) during the PWV ascending period are considered as predictive factors with which to forecast the precipitation event. The numerical results show that about 80%–90% of precipitation events and more than 90% of heavy rain events can be forecasted two to six hours in advance of the precipitation event based on the proposed method. 5-minute PWV data derived from GPS observations based on real-time precise point positioning (RT-PPP) were used for the typhoon event that passed over Zhejiang Province between 10 and 12 July, 2015. A good result was acquired using the proposed method and about 74% of precipitation events were predicted at some ten to thirty minutes earlier than their onset with a false alarm rate of 18%. This study shows that the GPS-based PWV was promising for short-term and now-casting precipitation forecasting. •This paper provides a precipitation forecasting method based on the GPS-derived PWV time series.•The estimated PWV derived from the self-developed PPP software is validated.•The proposed method has been tested using the precipitation data, and used for a typhoon event with a satisfied result.