[A-CG35] グローバル炭素循環の観測と解析

[ACG35-03] Impact of anomalous high temperature in the 2020 spring-summer season on the terrestrial carbon cycle in Russia

*田口 琢斗¹、市井 和仁¹、山本 雄平¹、Belikov Dmitry¹、Patra Prabir²、Naveen Chandra²、小槻 峻司¹、鈴木 和良²、檜山 哲哉³ (1.千葉大学 環境リモートセンシング研究センター、2.国立研究開発法人海洋研究開発機構、3.名古屋大学 宇宙地球環境研究所)

キーワード：陸域炭素循環、植生リモートセンシング、異常高温

The seasonal variations in the terrestrial carbon cycle across northern high-latitude zones are tightly associated with the timing and duration of the temperature variations. In the spring to summer of 2020, large parts of Russia experienced unprecedented hot weather, recording nearly +6°C; however, its long-lasting heatwave effects on the net ecosystem carbon balance remain unclear. Here, we analyzed Russia’s vegetation phenology in 2020 with Moderate Resolution Imaging Spectroradiometer (MODIS) sensor measurements and seasonal terrestrial carbon cycle variations using two-different approaches (Top-down and Bottom-up) CO₂ flux estimations. MODIS Land surface temperature (LST) represents extreme positive temperature anomalies in western and central Russia in the first half of 2020, which neatly agrees with the early onset of spring compared to the past 20 years. Two estimations models show enhanced carbon uptake from April to June in the center region (-0.13 ± 0.04 [PgC] in 2001-2019 vs. -0.2 [PgC] in 2020 by Top-down; -0.12 ± 0.03 [PgC] in 2001-2019 vs. -0.24 [PgC] in 2020 by Bottom-up). Revealed by detailed analysis, year-round increased total ecosystem respiration across all regions can be found in response to warming enhancement; its yearly amplified emission offset carbon uptake during the first half of 2020. This may be critical in investigating the impact of future extreme climates on the terrestrial carbon cycle across northern high-latitude regions.