2019 Fiscal Year Final Research Report

Development of shipborne GNSS water vapor observation system

Research Project

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Project/Area Number	17K18963
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Research Field	Social systems engineering, Safety engineering, Disaster prevention engineering, and related fields
Research Institution	Japan Agency for Marine-Earth Science and Technology
Principal Investigator	Fujita Mikiko 国立研究開発法人海洋研究開発機構, 地球環境部門(大気海洋相互作用研究プログラム), 研究員 (50426293)
Co-Investigator(Kenkyū-buntansha)	山田朋人北海道大学, 工学研究院, 准教授 (10554959) 菊森佳幹国立研究開発法人土木研究所, 土木研究所(水災害・リスクマネジメント国際センター), 研究員 (20415003) 牛山朋来国立研究開発法人土木研究所, 土木研究所(水災害・リスクマネジメント国際センター), 研究員 (50466257)
Project Period (FY)	2017-06-30 – 2020-03-31
Keywords	GNSS可降水量 / 船舶観測 / 観測システムシミュレーション実験 / LETKF
Outline of Final Research Achievements	The measuring of water vapor amount is essential for the understanding of the convective system that causes heavy precipitation. Especially for the heavy precipitation that occurs in the boreal summer around Japan, it's desired to observe the water vapor feature over the ocean at the leeward area that contains abundant water vapor. We developed the ship-borne analytic system for GNSS precipitable water vapor (PWV), which can estimate the PWV in real-time. Moreover, we investigated the impact of the oceanic water vapor for the forecast of the heavy precipitation event by the observing system simulation experiment. As a result, the accurate GNSS PWV was confirmed by the developed system; that accuracy was similar to the previous study. In the impact investigation, the forecast of heavy precipitation was corrected by the assimilation of oceanic water vapor, in particular, the data was necessary around the leeward area where the water vapor transport was significant.
Free Research Field	GNSS/GPS気象学
Academic Significance and Societal Importance of the Research Achievements	本研究の実験により、船舶上でのリアルタイム可降水量観測は実現の可能性が非常に高いことがわかった。今後実用が本格化するCLAS/MADOCAといった衛星経由のGNSS解析向け補助データ配信サービスを利用することで、インターネット回線を介せずにリアルタイムで海上可降水量を観測できる可能性が高い。またこのようなデータを気象予測に活用すれば豪雨などの予測精度を改善できる可能性が高い。