Faculty Profiles - KOTANI, Ayumi

Papers - KOTANI, Ayumi

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

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

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

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

Open Access

CiNii Research

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

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 Open Access

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 Open Access

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 Open Access

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)

<p>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.</p>

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 Open Access

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 Open Access

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 Open Access

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 Open Access

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 Open Access

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 Open Access

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 Open Access

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 Open Access

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

Open Access

Web of Science

Scopus

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

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Papers - KOTANI, Ayumi