Faculty Profiles - KOTANI, Ayumi

Papers - KOTANI, Ayumi

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Mining plant phenology records from Kanazawa, Japan in the 1807-1838 Kakuson Diary

Shin, N; Sasai, Y; Kotani, A; Saitoh, TM

INTERNATIONAL JOURNAL OF BIOMETEOROLOGY Vol. 68 ( 1 ) page： 125 - 131 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Biometeorology

Mining the various records of plant phenology before the era of modern weather observations is an important but challenging task. We mined descriptions of plant phenology in Kanazawa, Japan, during the first half of the nineteenth century in the Kakuson Diary. We retrieved records of full bloom of 28 plant species, appearance of 31 seasonal foods, and peak leaf colouring. In particular, we found more than 10 years of records of plum, peach, cherry blossoms, udo, and bamboo shoots in spring; watermelon in summer; and persimmon, chestnut, and peak leaf colouring in autumn. The records suggest that spring phenology during 1807 to 1838 was later and autumn phenology was earlier than now. Despite spatio-temporal uncertainty in records in old diaries, we need to mine records of plant phenology in more old diaries and publish them in English.

DOI： 10.1007/s00484-023-02576-3

Web of Science

Scopus

PubMed

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

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

CiNii Research

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

Web of Science

Scopus

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

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

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

Web of Science

Scopus

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

Web of Science

Scopus

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

CiNii Research

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

Web of Science

Scopus

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

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

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

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Papers - KOTANI, Ayumi