[A-CG35] グローバル炭素循環の観測と解析

[ACG35-P05] Analyzing changes in terrestrial carbon cycle using a terrestrial carbon cycle model, VISIT and an inversion based estimation

*市井 和仁¹、栗原 茜¹、王 汝慈¹、Naveen Chandra²、Patra Prabir² (1.千葉大学、2.海洋研究開発機構)

キーワード：炭素循環、陸域生態系、トップダウン・ボトムアップ手法

Atmospheric CO2 concentration and its global cycle play an important role in predicting future atmospheric CO2 concentration and climate change. Terrestrial carbon cycle is one the most uncertain parts due to its spatial heterogenity and differences in its response to climate variability. Thus, understanding of current terresrial carbon cycle is essential. In this study, we evaluated two independent estimations of terrestrial carbon cycle from 2001 to 2021 period. Top-down estimation provides land-atmosphere carbon exchanges from atmospheric CO2 observation and bottom-up estmation provides based on each process and each region. In this study, we used VISIT terrestrial carbon cycle model and machine-learning based estimations as bottom-up methods, and an inversion analysis outputs, MIROC4-ACTM inversion, as an top-down method. VISIT model outpus were overall consistent with other estimationa, such as machine-learning based and top-down estimations in terms of interannual variations. In particular, some regions such as Southeast Asia show good consistency. We will also report results of a series of sensitivity test, and discuss changes in terrestrial carbon cycle.