3:30 PM - 3:45 PM
[MTT37-06] GNSS precipitable water vapor distribution and vertical structure revealed by very dense GNSS observation network
Keywords:GNSS meteorology, Water vapor
The GNSS observation network in Japan is operated by the Geospatial Information Authority of Japan (GSI) (electronic reference points, over 1,300 points nationwide), and the amount of atmospheric delay or precipitable water estimated at some observation points is assimilated into numerical forecast model. On the other hand, since November 2019, SoftBank Corp. has started to operate its own GNSS observation network (hereafter referred to as "SoftBank network") of ultra-multipoint (over 3,300 points nationwide) for the purpose of upgrading its positioning services. In this study, using data from this Softbank network, we analyzed the detailed distribution of GNSS available precipitation during heavy rainfall in the Kyushu region and estimated the vertical structure using a tomography method.
During the target period, a stationary front was stagnant over northern Kyushu and a linear precipitation zone developed in Kumamoto and Fukuoka prefectures on August 12, 2021. GNSS precipitable water vapor around the area exceeded 70 mm, and there were several stations that recorded statistically extremely high values of precipitable water (e.g., 79.0 mm in the Goto Islands). At the stations where such high precipitable water amounts were observed at high frequencies, it became clear by using this very dense observation network that they were scattered locally more than expected. Tomographic estimation of the vertical structure of water vapor showed not only variations in the surface water vapor under the atmospheric boundary layer but also significant water vapor inflow around 2-3 km altitude.
The data used in this study for post-processing analysis of SoftBank's original GNSS sites were provided by SoftBank Corporation and ALES Corporation through the framework of the ”Consortium to utilize the original dense GNSS network by SoftBank for a wide area of earth science".
During the target period, a stationary front was stagnant over northern Kyushu and a linear precipitation zone developed in Kumamoto and Fukuoka prefectures on August 12, 2021. GNSS precipitable water vapor around the area exceeded 70 mm, and there were several stations that recorded statistically extremely high values of precipitable water (e.g., 79.0 mm in the Goto Islands). At the stations where such high precipitable water amounts were observed at high frequencies, it became clear by using this very dense observation network that they were scattered locally more than expected. Tomographic estimation of the vertical structure of water vapor showed not only variations in the surface water vapor under the atmospheric boundary layer but also significant water vapor inflow around 2-3 km altitude.
The data used in this study for post-processing analysis of SoftBank's original GNSS sites were provided by SoftBank Corporation and ALES Corporation through the framework of the ”Consortium to utilize the original dense GNSS network by SoftBank for a wide area of earth science".