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37
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Introduction
Remote sensing; Carbon cycle; Photosynthesis; Wetland Methane;
Field Spectroscopy; Long-term Monitoring Sites; Solar-Induced chlorophyll Fluorescence; Forest; Crop field; Wetland
Current institution
Additional affiliations
May 2019 - March 2022
Education
April 2013 - March 2019
Publications
Publications (37)
Simulating gross primary production (GPP) is a key objective of terrestrial ecosystem models, and many studies have shown that solar‐induced chlorophyll fluorescence (SIF) is a reliable proxy for GPP. This study combines SIF data with a process‐based vegetation integrative simulator for trace gases (VISIT‐SIF) model to enhance GPP simulations in th...
Wetlands play an essential role in the global greenhouse gas budget via carbon dioxide sequestration as well as methane emission. In recent decades, solar‐induced chlorophyll fluorescence (SIF) has been recognized as a remotely sensed proxy of gross primary productivity (GPP), which generates substrates for methane production. To examine the suitab...
Built upon a 5‐year field investigation and a 13‐year satellite data set, this study examines the intricate interrelationships among ecophysiological parameters of Larix gmelinii trees and the prevailing ecosystem, climatic, and environmental factors present in the Indigirka lowlands of northeastern Siberia. It identified spatial‐temporal patterns...
The taiga ecosystem in northeastern Siberia, a nitrogen-limited ecosystem on permafrost with a dry climate, changed during the extreme wet event in 2007. We investigated the normalized difference vegetation index (NDVI) as a satellite-derived proxy for needle production and compared it with ecosystem parameters such as soil moisture water equivalen...
Although multiple studies have used solar-induced chlorophyll fluorescence (SIF) of the crop canopy to estimate photosynthetic activity, the effect of canopy geometry (row orientation) on diurnal SIF remains uncertain. Using a combination of 3D canopy radiative transfer modeling and spectroscopic observations collected in a winter wheat field, we i...
Terrestrial ecosystem photosynthesis plays a crucial role in global carbon cycling. Solar-induced chlorophyll fluorescence (SIF) is a state-of-the-art proxy for ecosystem photosynthesis. Although satellite-derived SIF correlates with gross primary productivity (GPP), it needs to be complemented with ground-based measurements to better understand th...
The taiga ecosystem in northeastern Siberia, a nitrogen-limited ecosystem on permafrost with a dry climate, changed during the extreme wet event in 2007. We investigated the normalized difference vegetation index (NDVI) as a satellite-derived proxy of needle production and compared it with ecosystem parameters such as soil moisture water equivalent...
Solar-induced chlorophyll fluorescence (SIF) can represent gross primary productivity (GPP) in many types of terrestrial vegetation. In principle, the chlorophyll-a fluorescence signal responds to the amount of light absorption and the fraction of energy distribution in photosystems. Therefore, it is mechanistically linked with CO2 assimilation. Re...
The taiga forest, a semi-arid and nitrogen-limited ecosystem on permafrost, has changed under extreme wet events. This study aims to understand the changes that occurred in a larch forest in Eastern Siberia after the wet event of 2006–2007. In the summer of 2018, studies were conducted at the Spasskaya Pad Experimental Forest Station near Yakutsk,...
Arctic tundra wetlands may be an important source of dissolved organic carbon (DOC) in Arctic rivers and the Arctic Ocean under global warming. We investigated stable water isotopes and DOC concentration in wetlands, tributaries, and the mainstream at the lower reaches of the Indigirka River in northeastern Siberia during the summers of 2010–2014 t...
Solar-induced chlorophyll fluorescence (SIF) emissions were estimated by the "area-ratio Fraunhofer line depth (aFLD) method", a new retrieval methodology in spectra from a low spectral resolution (SR) spectroradiometer (MS-700: full width half maximum (FWHM) of 10 nm and spectral sampling interval of 3.3 nm), assisted with a scaling to reference S...
Arctic and boreal permafrost ecosystems in Eastern Siberia, considered crucial to the climate system and global carbon cycle, are particularly vulnerable to climate change. This study investigates carbon dioxide (CO2) exchange fluxes over northeastern Siberia from 2013 to 2015 in a taiga–tundra boundary ecosystem for which such measurements are sca...
With the global warming, the frequent and severe river floods in Arctic regions have affected the distribution of willows in river lowlands. To investigate the effect of floods, especially waterlogging, on nitrogen conditions for willows, we measured their foliar nitrogen content and isotopic composition (δ15N), under various hydrological condition...
Arctic wetlands are significant sources of atmospheric methane and the observed accelerated climate changes in the arctic could cause a change in methane dynamics. Methane oxidation would be the key process to control methane emission from wetlands. In this study, we determined the potential methane oxidation rate of the wetland soils of a taiga–tu...
Detecting year-to-year variability of the timing of the start of the growing season (SGS) and the end of the growing season (EGS) is an important task in accurately evaluating ecosystem functions and services under climate change in vulnerable ecosystems in Siberia. We constructed a degree-day model for estimating the SGS and EGS dates at a deciduo...
Arctic terrestrial ecosystems near the treeline in river lowlands are vulnerable to the changing climate and seasonal extreme events, including flooding. We set up a simple camera monitoring system to record the timings and durations of the leafy period and the spring flush of river water at three observation sites (Boydom [B]: 70.64°N, 148.15°E; K...
Flooding is one of the greatest disasters that produces strong effects on the ecosystem and livelihoods of the local population. Flood frequency is expected to increase globally making its risk assessment an urgent issue. In spring‐summer 2017, an extreme flooding occurred in the Indigirka River lowland of Northeastern Siberia that inundated a larg...
The warming trend in the Arctic region is expected to cause drastic changes including permafrost degradation and vegetation shifts. We investigated the spatial distribution of ice content and stable isotopic compositions of water in near-surface permafrost down to a depth of 1 m in the Indigirka River lowlands of northeastern Siberia to examine how...
Arctic wetlands are significant sources of atmospheric methane and the observed accelerated climate changes in the arctic could cause the change in methane dynamics, where methane oxidation would be the key process to control methane emission from wetlands. In this study we determined the potential methane oxidation rate of the wetland soils of a t...
The response of CH4 emission from natural wetlands due to meteorological conditions is important because of its strong greenhouse effect. To understand the relationship between CH4 flux and wetting, we observed interannual variations in chamber CH4 flux, as well as the concentration, δ13C, and δD of dissolved CH4 during the summer from 2009 to 2013...
An extreme flooding event occurred from June to July 2017 in the Indigirka River lowland of northeastern Siberia. We used Landsat 8 satellite surface reflectance data to detect the flood inundation area and extract water color for delineating different water sources. We also took direct samples of dissolved methane concentrations in the river water...
The tree-ring width index (RWI) and satellite-derived vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), are used as long-term indicators of the past forest carbon uptake. However, fundamental questions remain with respect to what is represented by the RWI and NDVI at the ecosystem level. To address this question, we com...
Taiga–tundra boundary ecosystems are affected by climate change. Methane (CH4) emissions in taiga–tundra boundary ecosystems have sparsely been evaluated from local to regional scales. We linked in situ CH4 fluxes (2009–2016) with vegetation cover, and scaled these findings to estimate CH4 emissions at a local scale (10 × 10 km) using high-resoluti...
The response of CH4 emission from natural wetlands to meteorological conditions is important because of its strong greenhouse effect. To understand relationship between CH4 flux and wetting, we observed interannual variations in chamber CH4 flux, and concentration, δ¹³C, and δD of dissolved CH4 in summers from 2009 to 2013 at the taiga-tundra bound...
Although stable carbon isotopic composition (δ ¹³ C) of plants has been widely used to indicate different water regimes in terrestrial ecosystems over the past four decades, the changes in the plant δ ¹³ C value under waterlogging have not been sufficiently clarified. With the enhanced global warming in recent years, the increasing frequency and se...
Site No., location, distance to river, dominant species, production, ANPP, and LAI for three 2.5 m × 2.5 m plots in summer of 2016.
The river water level (cm) from 1st June to 31st July, for the average in 2010–2014, 2015 and 2016.
The average river water level during 2010-2014 was shown in circles, the water level in 2015 and 2016 was shown in triangles and diamonds, respectively. The arrow lines indicate the observed growing season, with fast growing period in wide arrow line...
River water level data from 2010 to 2016.
Raw data for Figure A2.
Photosynthesis light response curve of willows under the light levels from 10 to 955 μmol m−2 s−1.
Photosynthesis light response curve of the willows S. boganidensis (red cycles), S. glauca (green triangles), and S. richardsonii (blue squares) under the light levels from 10 to 955 μmol m−2 s−1. The values were reported as means ± SD.
Results of foliar δ13C values (‰) on single shoot from bottom to top.
Raw data for Figure A3.
Results of foliar δ13C values (‰).
Including samples collected in 2015, 2016 and leaves for ADC measurements.
Data for photosynthesis light response curve of the willows S. boganidensis (red cycles), S. glauca (green triangles), and S. richardsonii (blue squares).
Details of sampling site with site No., sampling data, river name, hydrological information, willow species (sampling number) and location of this study.
I and K river represent Indigirka and Kryvaya river.
The foliar δ13C values (‰) of the leaves according to the leaf-open order.
The foliar δ13C values (‰) of the leaves according to the leaf-open order, upon single shoot at each point of PA (empty symbols) and PC (filled symbols) in SBoydom (circles) and SKA (triangles). The different points are shown in different symbols.
Data for ADC monitoring at SPh-PA, PB and PC under different hydrological conditions.
ADC monitoring includes especially photosynthetic activity and stomatal conductance.
We report long-term continuous phenological and sky images taken by time-lapse cameras through the Phenological Eyes Network (http://www.pheno-eye.org. Accessed 29 May 2018) in various ecosystems from the Arctic to the tropics. Phenological images are useful in recording the year-to-year variability in the timing of flowering, leaf-flush, leaf-colo...
To better understand the factors controlling the growth of larch trees in Arctic taiga-tundra boundary ecosystem, we conducted field measurements of photosynthesis, tree size, nitrogen (N) content, and isotopic ratios in larch needles and soil. In addition, we observed various environmental parameters, including topography and soil moisture at four...
