Geophysical phenomena associated with GPS observed PW during the passage of a typhoon

Global Positioning System (GPS) observed precipitable water (PW) during the passage of a Typhoon has been focussed with an especial emphasis on possible correlation between the origin of depression concerned and the solar geophysical parameters. We have studied three typhoons during the period 1996 to 1998. Similar trend of variation of all the parameters of interest is observed for all the cases. Because of similar nature and for simplicity we present here primarily the results of Typhoon Zeb (1998), when Taiwan experienced a severe Typhoon during 13th October to 20th October followed by a Babs during 21st October to 31st October. GPS data were collected from the eight of Central Weather Bureau's (CWB) GPS stations in Taiwan and one site in Tsukuba, Japan. GPS-observed PW time series demonstrate that PW is, in general, high before and during the occurrence of the Typhoon, and low after the Typhoon. Comparison of GPS-observed PW depletion with radiosonde observation acquired at the Taipei weather station shows a very good consistency. Simultaneous, correlation between GPS observed PW data during severe Typhoon activity with the solar geophysical phenomena was studied. Some interesting observations obtained from the correlation study are reported here. The results reveal an interesting sequence of solar-terrestrial events. A tentative conclusion is reached, suggesting an origin of the meteorological activity from atmospheric gravity waves generated in the center of activity of the depressions concerned.