Faculty Profiles - KOTANI, Ayumi

Comparison of ground temperature and permafrost conditions in the Arctic simulated by land surface process models of different complexity Open Access

PubMed

Mori, J; Saito, K; Miyazaki, S; Machiya, H; Ise, T; Sueyoshi, T; Yamazaki, T; Iijima, Y; Ikawa, H; O'oishi, R; Ohta, T; Katata, G; Kotani, A; Sato, A; Sato, H; Sugimoto, A; Suzuki, R; Tanaka, K; Nitta, T; Hajima, T; Burke, E; Park, H

BULLETIN OF GLACIOLOGICAL RESEARCH Vol. 42 page： 69 - 94 2024

Assessment of carbon storage and CO2 fluxes in a headwater spring wetland Open Access

Aoki Shota, Kotani Ayumi, Gomi Takashi, Yusuke Mizuuchi

Proceeding of Annual Conference Vol. 37 ( 0 ) page： 185 2024

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

In this study, the CO2 budget in a spring-fed wetland was measured and the results were reported. Spring-fed wetlands have different spatial characteristics than other wetlands, which may affect their CO2 fluxes and carbon sequestration. The study observed variations in CO2 fluxes from upstream to downstream of the spring-fed wetlands, and the effects of seasonal and environmental factors were also identified. Biomass and soil carbon content were also investigated, suggesting that carbon sequestration in the spring-fed wetlands is lower than in other areas. This provides new insights into the CO2 budget of spring-fed wetlands and is expected to contribute to a global CO2 budget model.

DOI： 10.11520/jshwr.37.0_185

Open Access

Winter temperature and growing season CO2 budgets of deciduous needle leaf forest in eastern Siberia

KOTANI Ayumi, NAKAI Taro, HIYAMA Tetsuya

Journal of Japanese Association of Hydrological Sciences Vol. 53 ( 0 ) page： 20 - 24 2023.3

テレビ番組映像によりモンゴルの遊牧景観における人々と生態系の関わりの時間変化を紐解く Reviewed

小谷亜由美

流域圏学会誌 Vol. 10 page： 31 - 40 2023

Carbon Cycles in Forests

Maximov, TC; Maksimov, AP; Kononov, AV; Kotani, A; Dolman, J

WATER-CARBON DYNAMICS IN EASTERN SIBERIA Vol. 236 page： 69 - 100 2019

Can Subdaily LST Be Constructed in High-Latitude Regions Using Polar Orbiting Satellites?

Zhiyan Liu, Kazuhito Ichii, Yuhei Yamamoto, Masahito Ueyama, Hideki Kobayashi, Tetsuya Hiyama, Ayumi Kotani, Trofim Maximov, Ryan C. Sullivan, Sébastien Biraud

IEEE Geoscience and Remote Sensing Letters Vol. 22 page： 1 - 5 2025

A Google Trends analysis of people's sense of seasons in Hokkaido Reviewed Open Access

Nagai Shin, Hiromi Nakagawa, Hiroshi Morimoto, Ayumi Kotani

Frontiers in Sustainable Tourism Vol. 3 2024.12

Decadal increases in carbon uptake offset by respiratory losses across northern permafrost ecosystems Open Access

Craig R. See, Anna-Maria Virkkala, Susan M. Natali, Brendan M. Rogers, Marguerite Mauritz, Christina Biasi, Stef Bokhorst, Julia Boike, M. Syndonia Bret-Harte, Gerardo Celis, Namyi Chae, Torben R. Christensen, Sara June Murner, Sigrid Dengel, Han Dolman, Colin W. Edgar, Bo Elberling, Craig A. Emmerton, Eugénie S. Euskirchen, Mathias Göckede, Achim Grelle, Liam Heffernan, Manuel Helbig, David Holl, Elyn Humphreys, Hiroki Iwata, Järvi Järveoja, Hideki Kobayashi, John Kochendorfer, Pasi Kolari, Ayumi Kotani, Lars Kutzbach, Min Jung Kwon, Emma R. Lathrop, Efrén López-Blanco, Ivan Mammarella, Maija E. Marushchak, Mikhail Mastepanov, Yojiro Matsuura, Lutz Merbold, Gesa Meyer, Christina Minions, Mats B. Nilsson, Julia Nojeim, Steven F. Oberbauer, David Olefeldt, Sang-Jong Park, Frans-Jan W. Parmentier, Matthias Peichl, Darcy Peter, Roman Petrov, Rafael Poyatos, Anatoly S. Prokushkin, William Quinton, Heidi Rodenhizer, Torsten Sachs, Kathleen Savage, Christopher Schulze, Sofie Sjögersten, Oliver Sonnentag, Vincent L. St. Louis, Margaret S. Torn, Eeva-Stiina Tuittila, Masahito Ueyama, Andrej Varlagin, Carolina Voigt, Jennifer D. Watts, Donatella Zona, Viacheslav I. Zyryanov, Edward A. G. Schuur

Nature Climate Change Vol. 14 ( 8 ) page： 853 - 862 2024.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

Tundra and boreal ecosystems encompass the northern circumpolar permafrost region and are experiencing rapid environmental change with important implications for the global carbon (C) budget. We analysed multi-decadal time series containing 302 annual estimates of carbon dioxide (CO2) flux across 70 permafrost and non-permafrost ecosystems, and 672 estimates of summer CO2 flux across 181 ecosystems. We find an increase in the annual CO2 sink across non-permafrost ecosystems but not permafrost ecosystems, despite similar increases in summer uptake. Thus, recent non-growing-season CO2 losses have substantially impacted the CO2 balance of permafrost ecosystems. Furthermore, analysis of interannual variability reveals warmer summers amplify the C cycle (increase productivity and respiration) at putatively nitrogen-limited sites and at sites less reliant on summer precipitation for water use. Our findings suggest that water and nutrient availability will be important predictors of the C-cycle response of these ecosystems to future warming.

DOI： 10.1038/s41558-024-02057-4

Open Access

Stochastic representation of spatial variability in thaw depth in permafrost boreal forests

Other Link： https://www.nature.com/articles/s41558-024-02057-4

Perspective and review: how to develop our understanding of temporal changes in the relationship between people and the landscape under societal and climate change in Northeast Asia? Reviewed Open Access

Nagai Shin, Taku M. Saitoh, Ayumi Kotani, Tomoaki Miura, Hiromi Nakagawa, Chifuyu Katsumata, Hiroshi Morimoto, Hideyuki Onishi

Frontiers in Environmental Science Vol. 12 page： 1236664 2024.2

Taro Nakai, Tetsuya Hiyama, Ayumi Kotani, Yoshihiro Iijima, Takeshi Ohta, Trofim C. Maximov

PERMAFROST AND PERIGLACIAL PROCESSES 2023.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

A simple stochastic representation of the spatial variability in thaw depth is proposed. Thaw depth distribution measured in the two larch-type forests in eastern Siberia, Spasskaya Pad and Elgeeii, showed different spatial, seasonal, and interannual variability, respectively. Year-to-year variation in active-layer thickness was minor in Spasskaya Pad compared to Elgeeii. A gamma distribution adequately represented both sites' thaw depth spatial variability as the cumulative probability. Thus, we developed a simple model using the gamma distribution that illustrates the spatial variability in thaw depth at any thawing stage as a function of a given mean thaw depth. A hierarchy of models was introduced that sequentially considered the constant state, linearity, and nonlinearity in the dependence of the rate parameter of the gamma distribution on the mean thaw depth. Although the requirements of the model levels differed between Spasskaya Pad and Elgeeii, the proposed model successfully represented the spatial variability in thaw depth at both sites during different thaw seasons.

DOI： 10.1002/ppp.2204

Perspective: Improving the accuracy of plant phenology observations and land-cover and land-use detection by optical satellite remote-sensing in the Asian tropics

Nagai Shin, Chifuyu Katsumata, Tomoaki Miura, Narumasa Tsutsumida, Tomoaki Ichie, Ayumi Kotani, Michiko Nakagawa, Kho Lip Khoon, Hideki Kobayashi, Tomo’omi Kumagai, Shunsuke Tei, Runi anak Sylvester Pungga, Taizo Yamada, Akihiro Kameda, Masayuki Yanagisawa, Kenlo Nishida Nasahara, Hiroyuki Muraoka, Kazuhito Ichii, Yuji Tokumoto

Frontiers in Forests and Global Change Vol. 6 2023.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers Media SA

Recent advances in satellite-borne optical sensors led to important developments in the monitoring of tropical ecosystems in Asia, which have been strongly affected by recent anthropogenic activities and climate change. Based on our feasibility analyses conducted in Indonesia in Sumatra and Sarawak, Malaysia in Borneo, we discuss the current situation, problems, recent improvements, and future tasks regarding plant phenology observations and land-cover and land-use detection. We found that the Multispectral Instrument (MSI) on board the Sentinel-2A/2B satellites with a 10-m spatial resolution and 5-day observational intervals could be used to monitor phenology among tree species. For the Advanced Himawari Imager (AHI) on board the Himawari-8 geostationary satellite with a 1,000-m spatial resolution and 10-min observational intervals, we found that the time-series in vegetation indices without gaps due to cloud contamination may be used to accurately detect the timing and patterns of phenology among tree species, although the spatial resolution of the sensor requires further improvement. We also found and validated that text and pictures with geolocation information published on the Internet, and historical field notes could be used for ground-truthing land cover and land use in the past and present time. The future development of both high frequency (≤ 10 min) and high spatial resolution (≤ 10 m) optical sensors aboard satellites is expected to dramatically improve our understanding of ecosystems in the tropical Asia.

DOI： 10.3389/ffgc.2023.1106723

Record mining of cherry flowering phenology in Tokyo during the Meiji and Taisho eras from Atomi Kakei's diary Reviewed

Shin Nagai, Kotani Ayumi, Maruya Yasuyuki

JAPANESE JOURNAL OF BIOMETEOROLOGY Vol. 59 ( 3-4 ) page： 89 - 99 2022.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Biometeorology

To evaluate the long-term relationship between climate change and plant phenology in spring, record mining of cherry flowering phenology before the Japan Meteorological Agency began recording phenological observations is an important task. We retrieved records of flowering phenology during the Meiji and Taisho eras from the diary of Atomi Kakei, a Japanese educator (1840−1926) and then evaluated the data quality and systematic errors. We were able to retrieve 22 years of flowering dates and 33 years of full-bloom dates across the period from 1873 to 1924. The flowering and full-bloom dates retrieved from this period were about 10 days later than those at present. The records of cherry flowering phenology in the diary may be considered to contain systematic errors of at least a few days caused by the differences of observation points and persons, discrete observation days, and differences of cherry species and individual trees but our findings indicated that diary records of the phenology of cherry flowering is useful for determining the phenological effects of climate change.

DOI： 10.11227/seikisho.59.89

Can Yandex statistics and google trends be used to detect people's interests in berries in the Russian Far East? International coauthorship

Shin Nagai, Ayumi Kotani, Yasuyuki Maruya, Tuyara Gavrilyeva

Polar Science Vol. 33 page： 100871 - 100871 2022.9

Monitoring of cherry flowering phenology with Google Trends Reviewed

Shin Nagai, Kotani Ayumi, Tei Shunsuke, Tsutsumida Narumasa

PLOS ONE Vol. 17 ( 7 ) 2022.7

Language：English Publishing type：Research paper (scientific journal) Publisher：PLoS ONE

Google Trends (GT) is an online tool designed for searching for changes over time. We assessed its use for evaluating changes in the timing of cherry flowering phenology, which is of intense interest to Japanese people. We examined the relationship between time-series of relative search volume (RSV: relative change in search requests over time obtained from the GT access engine) and cherry flowering information published on websites (as ground truth) in relation to three famous ancient cherry trees. The time-series of RSV showed an annual bell-shaped seasonal variability, and the dates of the maximum RSV tended to correspond to the dates of full bloom. Our results suggest that GT allows monitoring of multiple famous cherry flowering sites where we cannot obtain long-term flowering data to evaluate the spatiotemporal variability of cherry flowering phenology.

DOI： 10.1371/journal.pone.0271648

Contrasting 20-year trends in NDVI at two Siberian larch forests with and without multiyear waterlogging-induced disturbances Reviewed

The relationships between basin conditions and long-term runoff characteristics in Japanese basins with little snow by comparing tank model parameters

HOTTA Yuki, TANAKA Takafumi, KOTANI Ayumi

Journal of Japanese Association of Hydrological Sciences Vol. 52 ( 1 ) page： 1 - 22 2022.4

Hirohiko Nagano, Ayumi Kotani, Hiroki Mizuochi, Kazuhito Ichii, Hironari Kanamori, Tetsuya Hiyama

Environmental Research Letters Vol. 17 ( 2 ) 2022.2

The ABCflux database: Arctic-boreal CO2 flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems

Virkkala Anna-Maria, Natali Susan M., Rogers Brendan M., Watts Jennifer D., Savage Kathleen, Connon Sara June, Mauritz Marguerite, Schuur Edward A. G., Peter Darcy, Minions Christina, Nojeim Julia, Commane Roisin, Emmerton Craig A., Goeckede Mathias, Helbig Manuel, Holl David, Iwata Hiroki, Kobayashi Hideki, Kolari Pasi, Lopez-Blanco Efren, Marushchak Maija E., Mastepanov Mikhail, Merbold Lutz, Parmentier Frans-Jan W., Peichl Matthias, Sachs Torsten, Sonnentag Oliver, Ueyama Masahito, Voigt Carolina, Aurela Mika, Boike Julia, Celis Gerardo, Chae Namyi, Christensen Torben R., Bret-Harte M. Syndonia, Dengel Sigrid, Dolman Han, Edgar Colin W., Elberling Bo, Euskirchen Eugenie, Grelle Achim, Hatakka Juha, Humphreys Elyn, Jarveoja Jarvi, Kotani Ayumi, Kutzbach Lars, Laurila Tuomas, Lohila Annalea, Mammarella Ivan, Matsuura Yojiro, Meyer Gesa, Nilsson Mats B., Oberbauer Steven F., Park Sang-Jong, Petrov Roman, Prokushkin Anatoly S., Schulze Christopher, St Louis Vincent L., Tuittila Eeva-Stiina, Tuovinen Juha-Pekka, Quinton William, Varlagin Andrej, Zona Donatella, Zyryanov Viacheslav I.

EARTH SYSTEM SCIENCE DATA Vol. 14 ( 1 ) page： 179 - 208 2022.1

Seasonality in Human Interest in Berry Plants Detection by Google Trends Reviewed

Ayumi Kotani, Nagai Shin, Shunsuke Tei, Andrey Makarov, Tuyara Gavrilyeva

Frontiers in Forest Global Change Vol. 4 page： 688835 2021.9

Geographical, Climatological, and Biological Characteristics of Tree Radial Growth Response to Autumn Climate Change Reviewed

Shunsuke Tei, Ayumi Kotani, Atsuko Sugimoto, Nagai Shin

Frontiers in Forest Global Change Vol. 4 page： 687749 2021.8

Dynamic Mapping of Subarctic Surface Water by Fusion of Microwave and Optical Satellite Data Using Conditional Adversarial Networks

Mizuochi Hiroki, Iijima Yoshihiro, Nagano Hirohiko, Kotani Ayumi, Hiyama Tetsuya

REMOTE SENSING Vol. 13 ( 2 ) page： 1 - 19 2021.1

Author Correction: The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data (Scientific Data, (2020), 7, 1, (225), 10.1038/s41597-020-0534-3)

Pastorello G.

Scientific Data Vol. 8 ( 1 ) 2021

Seasonal variations in carbon dioxide exchange fluxes at a taiga–tundra boundary ecosystem in Northeastern Siberia

Shunsuke Tei, Tomoki Morozumi, Ayumi Kotani, Shinya Takano, Atsuko Sugimoto, Shin Miyazaki, Ryo Shingubara, Rong Fan, Roman Petrov, Egor Starostin, Ruslan Shakhmatov, Aleksandr Nogovitcyn, Trofim Maximov

Polar Science 2021

Lessons learned from more than a decade of greenhouse gas flux measurements at boreal forests in eastern Siberia and interior Alaska

Hiyama T.

Polar Science 2021

Detection of year-to-year spring and autumn bio-meteorological variations in siberian ecosystems

Nagai Shin, Kotani Ayumi, Morozumi Tomoki, Kononov Alexander V, Petrov Roman E, Shakhmatov Ruslan, Ohta Takeshi, Sugimoto Atsuko, Maximov Trofim C, Suzuki Rikie, Tei Shunsuke

POLAR SCIENCE Vol. 25 2020.9

Direct measurement of leaf area index in a deciduous needle-leaf forest, eastern Siberia

Shin Nagai, Kotani Ayumi, Sato Tomonori, Sugimoto Atsuko, Maximov Trofim C, Nogovitcyn Aleksandr, Miyamoto Yumiko, Kobayashi Hideki, Tei Shunsuke

POLAR SCIENCE Vol. 25 2020.9

The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

Pastorello Gilberto, Trotta Carlo, Canfora Eleonora, Chu Housen, Christianson Danielle, Cheah You-Wei, Poindexter Cristina, Chen Jiquan, Elbashandy Abdelrahman, Humphrey Marty, Isaac Peter, Polidori Diego, Ribeca Alessio, van Ingen Catharine, Zhang Leiming, Amiro Brian, Ammann Christof, Arain M. Altaf, Ardo Jonas, Arkebauer Timothy, Arndt Stefan K., Arriga Nicola, Aubinet Marc, Aurela Mika, Baldocchi Dennis, Barr Alan, Beamesderfer Eric, Marchesini Luca Belelli, Bergeron Onil, Beringer Jason, Bernhofer Christian, Berveiller Daniel, Billesbach Dave, Black Thomas Andrew, Blanken Peter D., Bohrer Gil, Boike Julia, Bolstad Paul V., Bonal Damien, Bonnefond Jean-Marc, Bowling David R., Bracho Rosvel, Brodeur Jason, Bruemmer Christian, Buchmann Nina, Burban Benoit, Burns Sean P., Buysse Pauline, Cale Peter, Cavagna Mauro, Cellier Pierre, Chen Shiping, Chini Isaac, Christensen Torben R., Cleverly James, Collalti Alessio, Consalvo Claudia, Cook Bruce D., Cook David, Coursolle Carole, Cremonese Edoardo, Curtis Peter S., D'Andrea Ettore, da Rocha Humberto, Dai Xiaoqin, Davis Kenneth J., De Cinti Bruno, de Grandcourt Agnes, De Ligne Anne, De Oliveira Raimundo C., Delpierre Nicolas, Desai Ankur R., Di Bella Carlos Marcelo, di Tommasi Paul, Dolman Han, Domingo Francisco, Dong Gang, Dore Sabina, Duce Pierpaolo, Dufrene Eric, Dunn Allison, Dusek Jiri, Eamus Derek, Eichelmann Uwe, ElKhidir Hatim Abdalla M., Eugster Werner, Ewenz Cacilia M., Ewers Brent, Famulari Daniela, Fares Silvano, Feigenwinter Iris, Feitz Andrew, Fensholt Rasmus, Filippa Gianluca, Fischer Marc, Frank John, Galvagno Marta, Gharun Mana, Gianelle Damiano, Gielen Bert, Gioli Beniamino, Gitelson Anatoly, Goded Ignacio, Goeckede Mathias, Goldstein Allen H., Gough Christopher M., Goulden Michael L., Graf Alexander, Griebel Anne, Gruening Carsten, Gruenwald Thomas, Hammerle Albin, Han Shijie, Han Xingguo, Hansen Birger Ulf, Hanson Chad, Hatakka Juha, He Yongtao, Hehn Markus, Heinesch Bernard, Hinko-Najera Nina, Hoertnagl Lukas, Hutley Lindsay, Ibrom Andreas, Ikawa Hiroki, Jackowicz-Korczynski Marcin, Janous Dalibor, Jans Wilma, Jassal Rachhpal, Jiang Shicheng, Kato Tomomichi, Khomik Myroslava, Klatt Janina, Knohl Alexander, Knox Sara, Kobayashi Hideki, Koerber Georgia, Kolle Olaf, Kosugi Yoshiko, Kotani Ayumi, Kowalski Andrew, Kruijt Bart, Kurbatova Julia, Kutsch Werner L., Kwon Hyojung, Launiainen Samuli, Laurila Tuomas, Law Bev, Leuning Ray, Li Yingnian, Liddell Michael, Limousin Jean-Marc, Lion Marryanna, Liska Adam J., Lohila Annalea, Lopez-Ballesteros Ana, Lopez-Blanco Efren, Loubet Benjamin, Loustau Denis, Lucas-Moffat Antje, Lueers Johannes, Ma Siyan, Macfarlane Craig, Magliulo Vincenzo, Maier Regine, Mammarella Ivan, Manca Giovanni, Marcolla Barbara, Margolis Hank A., Marras Serena, Massman William, Mastepanov Mikhail, Matamala Roser, Matthes Jaclyn Hatala, Mazzenga Francesco, McCaughey Harry, McHugh Ian, McMillan Andrew M. S., Merbold Lutz, Meyer Wayne, Meyers Tilden, Miller Scott D., Minerbi Stefano, Moderow Uta, Monson Russell K., Montagnani Leonardo, Moore Caitlin E., Moors Eddy, Moreaux Virginie, Moureaux Christine, Munger J. William, Nakai Taro, Neirynck Johan, Nesic Zoran, Nicolini Giacomo, Noormets Asko, Northwood Matthew, Nosetto Marcelo, Nouvellon Yann, Novick Kimberly, Oechel Walter, Olesen Jorgen Eivind, Ourcival Jean-Marc, Papuga Shirley A., Parmentier Frans-Jan, Paul-Limoges Eugenie, Pavelka Marian, Peichl Matthias, Pendall Elise, Phillips Richard P., Pilegaard Kim, Pirk Norbert, Posse Gabriela, Powell Thomas, Prasse Heiko, Prober Suzanne M., Rambal Serge, Rannik Ullar, Raz-Yaseef Naama, Reed David, de Dios Victor Resco, Restrepo-Coupe Natalia, Reverter Borja R., Roland Marilyn, Sabbatini Simone, Sachs Torsten, Saleska Scott R., Sanchez-Canete Enrique P., Sanchez-Mejia Zulia M., Schmid Hans Peter, Schmidt Marius, Schneider Karl, Schrader Frederik, Schroder Ivan, Scott Russell L., Sedlak Pavel, Serrano-Ortiz Penelope, Shao Changliang, Shi Peili, Shironya Ivan, Siebicke Lukas, Sigut Ladislav, Silberstein Richard, Sirca Costantino, Spano Donatella, Steinbrecher Rainer, Stevens Robert M., Sturtevant Cove, Suyker Andy, Tagesson Torbern, Takanashi Satoru, Tang Yanhong, Tapper Nigel, Thom Jonathan, Tiedemann Frank, Tomassucci Michele, Tuovinen Juha-Pekka, Urbanski Shawn, Valentini Riccardo, van der Molen Michiel, van Gorsel Eva, van Huissteden Ko, Varlagin Andrej, Verfaillie Joseph, Vesala Timo, Vincke Caroline, Vitale Domenico, Vygodskaya Natalia, Walker Jeffrey P., Walter-Shea Elizabeth, Wang Huimin, Weber Robin, Westermann Sebastian, Wille Christian, Wofsy Steven, Wohlfahrt Georg, Wolf Sebastian, Woodgate William, Li Yuelin, Zampedri Roberto, Zhang Junhui, Zhou Guoyi, Zona Donatella, Agarwal Deb, Biraud Sebastien, Torn Margaret, Papale Dario

SCIENTIFIC DATA Vol. 7 ( 1 ) 2020.7

Assessment of drought condition using remotely sensed drought severity index and its correlations with soil moisture product in Inner Mongolia

Wang Lusha, Kotani Ayumi, Tanaka Takafumi, Ohta Takeshi

THEORETICAL AND APPLIED CLIMATOLOGY Vol. 141 ( 1-2 ) page： 715 - 728 2020.7

Application of an open-path eddy covariance methane flux measurement system to a larch forest in eastern Siberia

Nakai Taro, Hiyama Tetsuya, Petrov Roman E., Kotani Ayumi, Ohta Takeshi, Maximov Trofim C.

AGRICULTURAL AND FOREST METEOROLOGY Vol. 282-283 2020.3

Application of Improved Remotely Sensed Drought Severity Index Based on Soil Moisture Product in Inner Mongolia

Wang Lusha, Kotani Ayumi, Tanaka Takafumi, Ohta Takeshi

SOLA Vol. 16 ( 0 ) page： 259 - 264 2020

Publishing type：Research paper (scientific journal) Publisher：公益社団法人日本気象学会

Based on the drought severity index (DSI), which is derived from the ratio of evapotranspiration (ET) to potential evapotranspiration (PET) and normalized difference vegetation index (NDVI), as measured by remote sensing, we replaced the ET/PET ratio with soil moisture (0-10 cm) to establish an improved index (IDSI) and evaluated the drought situation in Inner Mongolia. The two components in IDSI are independently derived; however, the effects of evapotranspiration are contained in the soil moisture, and even precipitation changes could be reflected. We used monthly IDSI data for Inner Mongolia to evaluate drought throughout the growing season (May–September) during 2001-2010. The IDSI showed that 2001, 2007, and 2009 were years with significant drought. Areas that experienced extreme drought were less extensive than those found by the DSI because we removed the ET/PET component, which already contains the effects of the NDVI. IDSI results not only contained the degree of precipitation change for a given month through soil moisture, but also reflected the influence of water and heat in the previous month through the NDVI. Moreover, IDSI results were generally consistent with agricultural drought disaster records.

DOI： 10.2151/sola.2020-043

Effects of extreme drought and wet events for tree mortality: Insights from tree-ring width and carbon isotope ratio in a Siberian larch forest

Tei Shunsuke, Sugimoto Atsuko, Yonenobu Hitoshi, Kotani Ayumi, Maximov Trofim C.

ECOHYDROLOGY Vol. 12 ( 8 ) 2019.12

Strong and stable relationships between tree-ring parameters and forest-level carbon fluxes in a Siberian larch forest

Tei Shunsuke, Sugimoto Atsuko, Kotani Ayumi, Ohta Takeshi, Morozumi Tomoki, Saito Soma, Hashiguchi Shuhei, Maximov Trofim

POLAR SCIENCE Vol. 21 page： 146 - 157 2019.9

Impact of unusually wet permafrost soil on understory vegetation and CO2 exchange in a larch forest in eastern Siberia Reviewed

Kotani Ayumi, Saito Atsushi, Kononov Alexander V, Petrov Roman E, Maximov Trofim C, Iijima Yoshihiro, Ohta Takeshi

AGRICULTURAL AND FOREST METEOROLOGY Vol. 265 page： 295 - 309 2019.2

Energy-water budget analysis of an Arctic terrestrial models intercomparison GTMIP Reviewed

SAITO Kazuyuki, MORI Junko, MACHIYA Hirokazu, MIYAZAKI Shin, ISE Takeshi, SUEYOSHI Tetshuo, YAMAZAKI Takeshi, IIJIMA Yoshihiro, IKAWA Hiroki, ICHII Kazuhito, ITO Akihiko, OʼOISHI Ryouta, OOTA Takeshi, KATATA Genki, KOTANI Ayumi, SASAI Takahiro, SATO Atsushi, SATO Hisashi, SUGIMOTO Atsuko, SUZUKI Rikie, TANAKA Katsunori, NITTA Tomoko, NIWANO Masashi, BURKE Eleanor, PARK Hotaek, YAMAGUCHI Satoru

Journal of the Japanese Society of Snow and Ice Vol. 80 ( 2 ) page： 159 - 174 2018

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society of Snow and Ice

An Arctic terrestrial model intercomparison project (GTMIP), designed for enhanced collaborations between modeling and field scientists, and for assessment of uncertainty and variations in current terrestrial models to improve, was carried out with 21 domestic and international participants, ranging from physical to biogeochemical to hybrid models. Metrics of the project covers energy-water budget, snowpack, phenology, subsurface regimes, and carbon budget. This paper reports the results on energy-water budget between the atmosphere, surface and subsurface, of the 34-year site simulations (1980-2013) for four GRENE-TEA sites with different eco-climate background (i.e., Fairbanks, Kevo, Tiksi, and Yakutsk). Models were driven by common, statistically fitted data created through model‒field collaborations with use of the site observations.
Energetic and hydrological balances between the atmosphere showed no systematic differences that result from disciplines that models are oriented to, but individual modelsʼ specifics. Modelsʼ performance at different sites were less associated with the types or complexity of the models than with the ecological and subsurface characteristics of the sites. The model ensemble proved to be a robust estimate to represent the observed values in general. However, snowpack and subsurface hydrological-thermal states, which greatly affect surface-subsurface exchanges, demonstrated large differences in performance and biases among models, which implies needs for special attention at future developments.

DOI： 10.5331/seppyo.80.2_159

Reconciliation of top-down and bottom-up CO2 fluxes in Siberian larch forest

Takata Kumiko, Patra Prabir K., Kotani Ayumi, Mori Junko, Belikov Dmitry, Ichii Kazuhito, Saeki Tazu, Ohta Takeshi, Saito Kazuyuki, Ueyama Masahito, Ito Akihiko, Maksyutov Shamil, Miyazaki Shin, Burke Eleanor J., Ganshin Alexander, Iijima Yoshihiro, Ise Takeshi, Machiya Hirokazu, Maximov Trofim C., Niwa Yosuke, O'ishi Ryo'ta, Park Hotaek, Sasai Takahiro, Sato Hisashi, Tei Shunsuke, Zhuravlev Ruslan, Machida Toshinobu, Sugimoto Atsuko, Aoki Shuji

ENVIRONMENTAL RESEARCH LETTERS Vol. 12 ( 12 ) 2017.12

New data-driven estimation of terrestrial CO2 fluxes in Asia using a standardized database of eddy covariance measurements, remote sensing data, and support vector regression

Ichii Kazuhito, Ueyama Masahito, Kondo Masayuki, Saigusa Nobuko, Kim Joon, Carmelita Alberto Ma., Ardoe Jonas, Euskirchen Eugenie S., Kang Minseok, Hirano Takashi, Joiner Joanna, Kobayashi Hideki, Marchesini Luca Belelli, Merbold Lutz, Miyata Akira, Saitoh Taku M., Takagi Kentaro, Varlagin Andrej, Bret-Harte M. Syndonia, Kitamura Kenzo, Kosugi Yoshiko, Kotani Ayumi, Kumar Kireet, Li Sheng-Gong, Machimura Takashi, Matsuura Yojiro, Mizoguchi Yasuko, Ohta Takeshi, Mukherjee Sandipan, Yanagi Yuji, Yasuda Yukio, Zhang Yiping, Zhao Fenghua

JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. 122 ( 4 ) page： 767 - 795 2017.4

Analysing the origin of rain- and subsurface water in seasonal wetlands of north-central Namibia

Hiyama Tetsuya, Kanamori Hironari, Kambatuku Jack R., Kotani Ayumi, Asai Kazuyoshi, Mizuochi Hiroki, Fujioka Yuichiro, Iijima Morio

ENVIRONMENTAL RESEARCH LETTERS Vol. 12 ( 3 ) 2017.3

Impact of rice cultivation on evapotranspiration in small seasonal wetlands of north-central Namibia

Kotani Ayumi, Hiyama Tetsuya, Ohta Takeshi, Hanamura Miho, R Kambatuku Jack, K Awala Simon, Iijima Morio

Hydrological Research Letters Vol. 11 ( 2 ) page： 134 - 140 2017

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Hydrology and Water Resources (JSHWR) / Japanese Association of Groundwater Hydrology (JAGH) / Japanese Association of Hydrological Sciences (JAHS) / Japanese Society of Physical Hydrology (JSPH)

This paper aims to evaluate the effect of mixed-cropping of rice and upland crops on evapotranspiration (ET) in a small seasonal wetland in the north-central Namibia. Meteorological observations were conducted in the experimental sloped field, which simulated the cultivation of both rice in a wetland environment and upland crops in the surrounding rain-fed area, and included a reference wetland with natural vegetation. During cultivation, ET from the rice field was similar to that from the wetland. However, during the dry period ET was remarkably reduced in the post-harvest field, while continuous ET occurred in the natural wetland even after surface water had dried up. The response of surface conductance to meteorological variables was investigated by means of the Jarvis–Stewart conductance model. During cultivation, surface conductance of the rice field and the wetland had a distinct stress response compared with that of the rain–fed crop field. During the dry period, surface conductance of the wetland site, in which the surface water dried–up, still responded to the meteorological conditions in contrast to those of the post-harvest field with plowed bare soil.

DOI： 10.3178/hrl.11.134

Factors contributing to soil nitrogen mineralization and nitrification rates of forest soils in the Japanese archipelago

Urakawa Rieko, Ohte Nobuhito, Shibata Hideaki, Isobe Kazuo, Tateno Ryunosuke, Oda Tomoki, Hishi Takuo, Fukushima Keitaro, Inagaki Yoshiyuki, Hirai Keizo, Oyanagi Nobuhiro, Nakata Makoto, Toda Hiroto, Kenta Tanaka, Kuroiwa Megumi, Watanabe Tsunehiro, Fukuzawa Karibu, Tokuchi Naoko, Ugawa Shin, Enoki Tsutomu, Nakanishi Asami, Saigusa Nobuko, Yamao Yukio, Kotani Ayumi

FOREST ECOLOGY AND MANAGEMENT Vol. 361 page： 382 - 396 2016.2

Persistence and memory timescales in root-zone soil moisture dynamics

Ghannam Khaled, Nakai Taro, Paschalis Athanasios, Oishi Christopher A., Kotani Ayumi, Igarashi Yasunori, Kumagai Tomo'omi, Katul Gabriel G.

WATER RESOURCES RESEARCH Vol. 52 ( 2 ) page： 1427 - 1445 2016.2

The GRENE-TEA model intercomparison project (GTMIP) Stage 1 forcing data set

Sueyoshi T.

Earth System Science Data Vol. 8 ( 1 ) page： 1 - 14 2016.1

The effect of assimilating satellite-derived soil moisture data in SiBCASA on simulated carbon fluxes in Boreal Eurasia

van der Molen M. K., de Jeu R. A. M., Wagner W., van der Velde I. R., Kolari P., Kurbatova J., Varlagin A., Maximov T. C., Kononov A. V., Ohta T., Kotani A., Krol M. C., Peters W.

HYDROLOGY AND EARTH SYSTEM SCIENCES Vol. 20 ( 2 ) page： 605 - 624 2016

The GRENE-TEA model intercomparison project (GTMIP) Stage 1 forcing data set

Sueyoshi T., Saito K., Miyazaki S., Mori J., Ise T., Arakida H., Suzuki R., Sato A., Iijima Y., Yabuki H., Ikawa H., Ohta T., Kotani A., Hajima T., Sato H., Yamazaki T., Sugimoto A.

EARTH SYSTEM SCIENCE DATA Vol. 8 ( 1 ) page： 1-14 2016

The effect of assimilating satellite derived soil moisture in SiBCASA on simulated carbon fluxes in Boreal Eurasia

Van Der Molen M.

Hydrology and Earth System Sciences Discussions Vol. 12 ( 9 ) page： 9003 - 9054 2015.9

Biogeochemical nitrogen properties of forest soils in the Japanese archipelago

Urakawa Rieko, Ohte Nobuhito, Shibata Hideaki, Tateno Ryunosuke, Hishi Takuo, Fukushima Keitaro, Inagaki Yoshiyuki, Hirai Keizo, Oda Tomoki, Oyanagi Nobuhiro, Nakata Makoto, Toda Hiroto, Kenta Tanaka, Fukuzawa Karibu, Watanabe Tsunehiro, Tokuchi Naoko, Nakaji Tatsuro, Saigusa Nobuko, Yamao Yukio, Nakanishi Asami, Enoki Tsutomu, Ugawa Shin, Hayakawa Atsushi, Kotani Ayumi, Kuroiwa Megumi, Isobe Kazuo

ECOLOGICAL RESEARCH Vol. 30 ( 1 ) page： 1-2 2015.1

The GRENE-TEA model intercomparison project (GTMIP): overview and experiment protocol for Stage 1

Miyazaki S., Saito K., Mori J., Yamazaki T., Ise T., Arakida H., Hajima T., Iijima Y., Machiya H., Sueyoshi T., Yabuki H., Burke E. J., Hosaka M., Ichii K., Ikawa H., Ito A., Kotani A., Matsuura Y., Niwano M., Nitta T., O'ishi R., Ohta T., Park H., Sasai T., Sato A., Sato H., Sugimoto A., Suzuki R., Tanaka K., Yamaguchi S., Yoshimura K.

Geoscientific Model Development Vol. 8 ( 9 ) page： 2841 - 2856 2015

Radiative and precipitation controls on root zone soil moisture spectra

Nakai Taro, Katul Gabriel G, Kotani Ayumi, Igarashi Yasunori, Ohta Takeshi, Suzuki Masakazu, Kumagai Tomo'omi

GEOPHYSICAL RESEARCH LETTERS Vol. 41 ( 21 ) page： 7546 - 7554 2014.11

Radiative and precipitation controls on root zone soil moisture spectra Reviewed

Nakai, T., Katul, G.G., Kotani, A., Igarashi, Y., Ohta, T., Suzuki, M., Kumagai, T.

Geophysical Research Letters Vol. 41 page： 7546-7554 2014.11

Effects of waterlogging on water and carbon dioxide fluxes and environmental variables in a Siberian larch forest, 1998-2011

Ohta Takeshi, Kotani Ayumi, Iijima Yoshihiro, Maximov Trofim C., Ito Syogo, Hanamura Miho, Kononov Alexander V., Maximov Ayal P.

AGRICULTURAL AND FOREST METEOROLOGY Vol. 188 page： 64 - 75 2014.5

Sap flow changes in relation to permafrost degradation under increasing precipitation in an eastern Siberian larch forest. Ecohydrology

Iijima, Y, Ohta, T, Kotani, A, Fedorov, A, Kodama, Y, Maximov, T

Ecohydrology Vol. 7 ( 2 ) page： 177 - 187 2014.4

Temporal variations in the linkage between the net ecosystem exchange of water vapour and CO2 over boreal forests in eastern Siberia

Kotani, A, Kononov, A, Ohta, T, Maximov, T

Ecohydrology Vol. 7 ( 2 ) page： 209 - 225 2014.4

Language：English Publishing type：Research paper (scientific journal)

This study investigated evapotranspiration and CO2 exchange, observed by the eddy covariance method, over two larch-dominated forests, in the middle part of the Lena basin, eastern Siberia. Compared with the Spasskaya Pad (SP) forest, the Elgeeii (EG) forest had more plant biomass and a soil texture that allowed for larger water retention. Observations in three growing seasons revealed that the two sites had similar seasonal patterns of meteorological conditions and almost the same total evapotranspiration; however, the net and gross uptakes of CO2 at the EG forest were 1·61 and 1·31 times those at the SP forest, respectively. The difference in aboveground biomass was probably responsible for the higher productivity at EG. Less aboveground biomass would result in less transpiration by trees at SP, which would be compensated for in total evapotranspiration by soil evaporation and transpiration by the forest floor vegetation. It is likely that forest transpiration is commonly optimized to the same level of evapotranspiration under similar meteorological conditions through differences in the contributions of evapotranspiration from the forest floor vegetation and the soil water availability. Water use efficiency (WUE) displayed different patterns, reflecting the seasonal variations in each flux. Seasonal sequences in the WUE at EG indicated a midsummer depletion, which is commonly observed in forest ecosystems under a broad climate. Daily variation corresponding to the vapour pressure deficit and the cloud cover conditions (reduced solar radiation) was also observed. In contrast, WUE was relatively invariable at the seasonal and daily scales at SP.

DOI： 10.1002/eco.1449

Water, Energy and Carbon Cycle in the Larch Wood of East Siberia

International Joint Conference of 11th AsiaFlux International Workshop, 3rd HESSS and 14th Annual Meeting of KSAFM “Communicating Science to Society: Coping with Climate Extremes for Resilient Ecological-Societal Systems”の報告

丸山篤志, 宮崎真, 小谷亜由美, 栗林正俊, 斎藤琢, 小野圭介

生物と気象 Vol. 14 page： D1-7 2014.1

Effects of waterlogging on water and carbon dioxide fluxes and environmental variables in a Siberian larch forest Reviewed

Ohta, T., Kotani, A., Iijima, Y., Maximov, T., Ito, S., Hanamura, M., Kononov, A., Maximov, A.

Agricultural and Forest Meteorology Vol. 188 page： 64-75 2014.1

OHTA Takeshi, KOTANI Ayumi

Water Science Vol. 58 ( 5 ) page： 43 - 73 2014

Primary factors in interannual variation of latent heat fluxes from overstory and understory in Siberian larch forest

Saito Atsushi, Kotani Ayumi, Ohta Takeshi, Iijima Yoshihiro

The Japanese Forest Society Congress Vol. 125 ( 0 ) page： 146 - 146 2014

Changes in eco-hydrological systems under recent climate change in eastern Siberia Reviewed

Hiyama TETSUYA, Ohta TAKESHI, Sugimoto ATSUKO, Yamazaki TAKESHI, Oshima KAZUHIRO, Yonenobu HITOSHI, Yamamoto KAZUKIYO, Kotani AYUMI, Park HOTAEK, Kodama Yuji, ther

IAHS Publication Vol. 360 page： 155 - 160 2013.1

Language：English Publishing type：Research paper (scientific journal)

Global warming is likely to transform Siberian environments. Recent eco-hydrological evidence indicates that water and carbon cycles have been changing rapidly, with potentially serious effects on the Siberian flora and fauna. We have comprehensively analysed dendrochronological, hydrological, and meteorological data and satellite remote sensing data to track changes in vegetation and the water and carbon cycles in the Lena River Basin, eastern Siberia. The basin is largely covered with larch forest and receives little precipitation. However, from 2005 to 2008 the central part of the basin experienced an extraordinarily high level of precipitation in late summer and winter. This resulted in the degradation of permafrost, forest, and hydrological elements in the region. Dendrochronological data implied that this event was the only incidence of such conditions in the previous 150 years. Based on data collected before and after the event, we developed a permafrost-ecosystem model, including surface soil freeze-thawing processes, to better represent the heat, water, and carbon fluxes in the region. We focused on the surface soil layer, in which an increased thawing depth is now apparent, surface soil moisture, and net primary production. An analysis of observed and model-simulated data indicated that the annual maximum thawing depth (AMTD) had increased gradually on a decadal scale and deepened abruptly after 2005. Climatological analyses of atmospheric water circulation over the region indicated that the recent increases in precipitation over the central Lena River Basin were partly related to cyclone activity. Consequently, the increased precipitation from late-summer to winter resulted in increases in soil moisture, soil temperature, and AMTD in the region. © 2013 IAHS Press.

Changes in eco-hydrological systems under recent climate change in eastern Siberia

Other Link： http://orcid.org/0000-0002-1596-7543

Changes in eco-hydrological systems under recent climate change in eastern Siberia

Hiyama Tetsuya, Ohta Takeshi, Sugimoto Atsuko, Yamazaki Takeshi, Oshima Kazuhiro, Yonenobu Hitoshi, Yamamoto Kazukiyo, Kotani Ayumi, Park Hotaek, Kodama Yuji, Hatta Shigemi, Fedorov Alexander N., Maximov Trofim C.

COLD AND MOUNTAIN REGION HYDROLOGICAL SYSTEMS UNDER CLIMATE CHANGE: TOWARDS IMPROVED PROJECTIONS Vol. 360 page： 155 - 160 2013

Hiyama T.

IAHS-AISH Proceedings and Reports Vol. 360 page： 155 - 160 2013

Interannual variation of evapotranspiration in an eastern Siberian larch forest

Xue Bao-Lin, Komatsu Hikaru, Kumagai Tomo'omi, Kotani Ayumi, Otsuki Kyoichi, Ohta Takeshi

HYDROLOGICAL PROCESSES Vol. 26 ( 15 ) page： 2360 - 2368 2012.7

Seasonal variability of scalar turbulent transport above forest canopy

Kotani Ayumi, Hamazaki Shunki, Ohta Takeshi

Proceeding of Annual Conference Vol. 25 ( 0 ) page： 276 - 276 2012

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

This study investigates seasonal variation in applicability of the turbulent similarity theory, and similarity or dissimilarity in the scalar transfer characteristics observed over forest canopy in the tropical monsoon, temperate, and boreal region. Deviation from the similarity theory and the small transfer efficiency was observed for CO2 variation at the boreal and temperature variation at the cool-temperate forest. Forests including deciduous trees showed clear seasonal variation in not only scalar flux itself but also its transfer characteristics especially in the case of CO2 variation, while the evergreen forest did not present such seasonal variation.

DOI： 10.11520/jshwr.25.0.276.0

Spatial variations in evapotranspiration over East Asian forest sites. I. Evapotranspiration and decoupling coefficient

Spatial variations in evapotranspiration over East Asian forest sites. II Surface conductance and aerodynamic conductance Reviewed

Khatun R, Ohta T, Kotani A, Asanuma J, Gamo M, Han S, Hirano T, Nakai Y, Saigusa N, Takagi K, Wang H, Yoshifuji N

Hydorological Rearch Letters ( 5 ) page： 88-92 2011

Spatial variations in evapotranspiration over East Asian forest sites. I. Evapotranspiration and decoupling coefficient Reviewed

Khatun R, Ohta T, Kotani A, Asanuma J, Gamo M, Han S, Hirano T, Nakai Y, Saigusa N, Takagi K, Wang H, Yoshifuji N

Hydorological Rearch Letters ( 5 ) page： 83-87 2011

Khatun Rehana, Ohta Takeshi, Kotani Ayumi, Asanuma Jun, Gamo Minoru, Han Shijie, Hirano Takashi, Nakai Yuichiro, Saigusa Nobuko, Takagi Kentaro, Wang Huimin, Yoshifuji Natsuko

Hydrological Research Letters Vol. 5 ( 5 ) page： 83 - 87 2011

Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Society of Hydrology and Water Resources (JSHWR) / Japanese Association of Groundwater Hydrology (JAGH) / Japanese Association of Hydrological Sciences (JAHS) / Japanese Society of Physical Hydrology (JSPH)

Evapotranspiration (ET) is not only a vital component of water budget, but also plays an important role in the energy budget of the earth-atmospheric system, ultimately driving many regional and global scale climatological processes. This paper describes the ET characteristics and factors controlling ET across the 17 forest sites in East Asia (2°S to 64°N latitude). ET was measured using the eddy covariance technique at each site. Daytime dry-canopy data for the growing season were used in this study. Growing season mean ET gradually decreased as latitude increased, with a range of 4.4 to 1.2 mm d−1. The growing season mean decoupling coefficient (Ω) ranged from 0.42 to 0.11 across the studied sites. At low-latitude forest sites, Ω was close to 0.50, indicating that the bulk surface was partially decoupled from the atmosphere and ET was strongly controlled by net radiation and vapour pressure deficit. At high-latitude forest sites, Ω was low (∼0.12), indicating that the bulk surface was well coupled to the atmosphere and ET was mainly controlled by surface conductance. The value of Ω was determined mainly by the ratio of aerodynamic conductance to surface conductance across the studied forests of East Asia.

DOI： 10.3178/hrl.5.83

Evapotranspiration over larch forest in southern area of eastern Siberia

Kotani Ayumi, Ohta Takeshi, Maximov Trofim

The Japanese Forest Society Congress Vol. 123 ( 0 ) page： Pb083 - Pb083 2011

Spatial variations in evapotranspiration over East Asian forest sites. II. Surface conductance and aerodynamic conductance

Khatun Rehana, Ohta Takeshi, Kotani Ayumi, Asanuma Jun, Gamo Minoru, Han Shijie, Hirano Takashi, Nakai Yuichiro, Saigusa Nobuko, Takagi Kentaro, Wang Huimin, Yoshifuji Natsuko

Hydrological Research Letters Vol. 5 ( 5 ) page： 88 - 92 2011

Evapotranspiration over forest surfaces is mainly constrained by environmental and forest structural components through their influence on surface conductance (Gs) and aerodynamic conductance (Ga). Tower based eddy covariance data from 16 forest sites in East Asia (2°S to 64°N) were used to examine the sensitivity of Matsumoto and Nakai models for predicting Gs and Ga, respectively. Daytime dry-canopy data for the growing season were used in this study. Comparisons between model predictions and observed Gs and Ga showed good agreement, suggesting that the models were suitable for predicting Gs and Ga with reasonable accuracy. However, the model for Gs was unable to predict Gs accurately when soil water content was low (∼10%). In this circumstance, effective soil water content and a more comprehensive method for modelling the soil water content function must be used. Gs in East Asia was largely depended on vapour pressure deficit and secondarily on soil water content. Ga was largely affected by leaf area index compared with stand density.

DOI： 10.3178/hrl.5.88