日本地球惑星科学連合2019年大会

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[J] 口頭発表

セッション記号 A (大気水圏科学) » A-CG 大気海洋・環境科学複合領域・一般

[A-CG39] 陸域生態系の物質循環

2019年5月28日(火) 10:45 〜 12:15 301A (3F)

コンビーナ:加藤 知道(北海道大学農学研究院)、市井 和仁(千葉大学)、伊勢 武史(京都大学フィールド科学教育研究センター)、寺本 宗正(国立環境研究所)、座長:加藤 知道(北海道大学)

11:15 〜 11:30

[ACG39-09] Interactions between topography, permafrost, and vegetation in Siberian larch forest: a simulation study

*佐藤 永1 (1.海洋研究開発機構 北極環境変動総合研究センター)

キーワード:永久凍土、動的全球植生モデル、カラマツ、TOPMODEL

In eastern Siberia, larches (Larix spp.) often exist in pure stands, constructing the world's largest coniferous forest, of which changes can significantly affect the earth's albedo and the global carbon balance. Siberian larch area locates on the environmental edge of existence of forest ecosystem, and hence small difference in environmental condition alters existence of larch trees.

Indeed, there is a quantitative pattern that topographic properties controls the abundance of larch forest via both drought and flooding stresses in this region; larch abundance appears to be controlled by drought stress in mountainous regions, while controlled by flooding stresses in plain areas (Sato& Kobayashi 2018). Besides, this region is underlaid by permafrost, vegetation productivity is constraint by depth of active layer; plant productivity becomes lower for shallower active layer by reducing liquid-state-water holding capacity (Beers et al. 2007 ). At the same time, active layer depth is a function of soil wetness, because wetland soil has larger ice content in active layer, which facilitates downward heat conduction to the permafrost, resulting in shallow thaw for the active layers (Woo & Xia 1996).

To reconstruct such complicated interactions between topography, permafrost, and vegetation in Siberian larch forest, the TOPMODEL, which is a physically based streamflow and water-table-depth computation scheme was implemented to a dynamic vegetation model SEIB-DGVM (Sato et al. 2016), which works with a thermohydrology model. In this presentation, I will talk how this integrated model reasonably works, and how it can be employed for future projection of environmental conditions of the Siberian larch region.

Citations
Beer, C., et al. (2007). "Effects of soil freezing and thawing on vegetation carbon density in Siberia: A modeling analysis with the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ-DGVM)." Global Biogeochemical Cycles 21(1).

Carey, S. K. and M.-k. Woo (1998). A Case Study of Active Layer Thaw and Its Controlling Factors. 7th International Permafrost Conference. Yellowknife, NWT: 127-132.

Sato, H., et al. (2016). "Endurance of larch forest ecosystems in eastern Siberia under warming trends." Ecol Evol 6(16): 5690-5704.

Sato, H. and H. Kobayashi (2018). "Topography Controls the Abundance of Siberian Larch Forest." Journal of Geophysical Research-Biogeosciences 123(1): 106-116.

Woo, M. K. and Z. J. Xia (1996). "Effects of hydrology on the thermal conditions of the active layer." Nordic Hydrology 27(1-2): 129-142.