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山貫 緋称*; 市井 和仁*; 山本 雄平*; 小槻 峻司*; 寺本 宗正*; Sun, L.*; 永野 博彦*; 平野 高司*; 高木 健太郎*; 石田 祐宣*; et al.
no journal, ,
Soil respiration (SR) is one of the most essential components of soil carbon cycles. However, large uncertainties remain in its temporal and spatial variations. In this study, we updated our data-driven estimation of SR across Japan with observation data (eight sites across Japan), remote sensing data (MODIS land products), and random forest regression. We used soil temperature and moisture by a process-based model, the Simple Biosphere model including Urban Canopy (SiBUC). Our estimation shows a reasonable performance with R
=0.70 for the best model. Based on the established model, we estimated SR across Japan with a spatial resolution of 4 km from 2006 to 2018. Intercomparison of our estimation with other available datasets was also conducted to confirm consistent observation approach is important to upscale SR.
Sun, L.*; Liang, N.*; 高橋 善幸*; 平野 高司*; 石田 祐宣*; 高木 正博*; 高木 健太郎*; 寺本 宗正*; 近藤 俊明*; 小嵐 淳; et al.
no journal, ,
Methane (CH
) is one of the major greenhouse gases with a warming potential about 30 times greater than carbon dioxide. In terrestrial ecosystems, aerated soils are the only atmospheric CH sink through the effect of CH oxidizing bacteria, especially in forest soils. Soil CH uptake by forest soils has been linked to soil property, soil water content (SWC), soil temperature (T
) and precipitation, however the impact of vegetations are still limited understood. To validate the control of root activity on soil CH uptakes, we measured soil respiration and heterotrophic respiration rates and CH flux in five representative Japanese forests. CH flux peaked in summer and increased with increasing T and decreasing SWC in all five forests. Among the five sites, seasonal mean soil CH uptake positively correlated to root respiration which is evaluated from the difference between soil and heterotrophic respirations. Our results indicate that root activity is an important parameter for modelling soil CH uptake in forest ecosystems.