[A-CG35] グローバル炭素循環の観測と解析

[ACG35-02] Analysis of XCO₂ variability at Saga, Tsukuba and Rikubetsu, Japan using WRF-GHG model

*Jagat Bisht¹、Prabir K. Patra^1,2、Masayuki Takigawa¹、Masahiro Yamaguchi¹、Yugo Kanaya¹、Isamu Morino³、Hirofumi Ohyama³、Kei Shiomi⁴ (1.Research Institute for Global Change, JAMSTEC, Yokohama, 235-0019, Japan、2.Center for Environmental Remote Sensing, Chiba University, Chiba, 263-8522, Japan、3.Earth System Division, NIES, Tsukuba, Ibaraki, 305-8506, Japan、4.Earth Observation Research Center, JAXA, Tsukuba, Ibaraki, 305-8505, Japan)

キーワード：XCO2, WRF-GHG, TCCON

CO₂ is a well-mixed and long-lived greenhouse gas (GHG) in the atmosphere which has both anthropogenic and natural sources. CO₂ concentration is increasing steadily in the atmosphere because emissions by anthropogenic activity. Several CO₂ observing satellites, measuring total column dry-air mole fractions (XCO₂), are in the Earth’s orbit and many GHG observing dedicated satellite missions set to be launched in the coming years. The ground based XCO₂ observing networks like TCCON (Total Carbon Column Observing Network) provide critical XCO₂ data for satellite retrievals validation and model simulation. This study simulates CO₂ using Weather Research and Forecasting coupled with GHG modules (WRF-GHG) with central grid over Japan and at 27 km spatial resolution for the year 2019. We analyzed TCCON XCO₂ using both the global and regional modeling frameworks. The XCO₂ is found to be significantly influenced by the CO₂ concentration from higher atmospheric pressure levels (>400 hPa). We take the advantage of the high-top global Atmospheric Chemistry-Transport model (MIROC4-ACTM) with well-resolved stratosphere to better represent variabilities in XCO₂. Observations from three TCCON sites over Japan were analyzed for this study; namely, Saga (130.3^oE, 33.2^oN), Tsukuba (140.1^oE, 36.0^oN), and Rikubetsu (143.7^oE, 43.4^oN). It has been found that correlation improved between observed and model simulated XCO₂ by using a hybrid model CO₂ concentration profile data which is a combination of regional WRF-GHG and global MIROC4-ACTM; We used MIROC4-ACTM CO₂ concentrations at higher altitudes (<400 hPa) with the WRF-GHG CO₂ output at lower altitudes. The correlation improvement between observed and simulated XCO₂ concentrations is most prominent over Saga (~35%), which is in proximity to high CO₂emission/sink regions such as China, Korea and southeast Asia.

Acknowledgements: The TCCON data were obtained from the TCCON Data Archive hosted by CaltechDATA (https://tccondata.org) for sites managed by NIES, and JAXA, Japan.