[A-CG46] Biogeochemical Cycles in Land Ecosystem

[ACG46-06] Multi-vertical layer observations of canopy chlorophyll fluorescence in tropical and temperate forests

*Tomoki Morozumi¹, Hibiki M Noda¹, Tomomichi Kato², Hiroyuki Muraoka³, Tatsuro Nakaji², Satoru Takanashi⁴, Yoshiko Kosugi⁵, Marryanna Lion⁶ (1.National Institute for Environmental Studies (NIES), 2.Hokkaido University, 3.Gifu University, 4.Forestry and Forest Products Research Institute, 5.Kyoto University, 6.Forest Research Institute Malaysia (FRIM))

Keywords:optical remote sensing, photosynthesis, Southeast Asia, tower observation

Tropical forests are the most diverse and vertically heterogeneous among terrestrial ecosystems, which play an essential role in the global carbon cycle. In the stratified forest, which exhibits the assembly of tall trees, seedlings, and small herbaceous plants, the light utilization of vertical profile is key to understanding variations of carbon uptake. In the present study, we focused on chlorophyll fluorescence in overstory and understory as a proxy for CO₂ assimilation rate. We used the Fraunhofer-line approach to retrieve solar-induced chlorophyll fluorescence (SIF) at the canopy scale with tower-mounted fine spectral visible-near-infrared sensors to detect fluorescence at 760 nm wavelength. The results include a diurnal and seasonal analysis of the tropical evergreen broadleaved forest at the 52 m tower in inland Peninsular Malaysia in 2024. The implication of ecophysiological function will be discussed in comparison with the previous report on a temperate forest in Gifu, central Japan.