Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publisher：Quaternary Science Reviews  

Tree-ring cellulose oxygen isotope (δ18O) in monsoon Asia (MA) is affected collectively by local hydroclimate and remote oceanic-atmospheric variations. Variations of tree-ring δ18O have been widely used for quantitative reconstructions of monsoon-season precipitation, relative humidity and drought severity. However, local hydroclimate and remote large-scale circulation's influences on tree-ring δ18O has not been fully resolved. Here, we collected 24 tree-ring δ18O chronologies covering the period of 1884–1999 across a wide range of MA and investigated the common signals of these chronologies using principal component analysis. The first principal component (PC1) of the 24 tree-ring δ18O chronologies explained 25.2% of the total variances and showed significant positive correlations with the observed Asian summer monsoon oxygen isotope index (r = 0.69) during the period of 1978–1999, suggesting that a common signal of precipitation δ18O does exist in MA and that it is highly correlated with El Niño–Southern Oscillation (ENSO) (r = 0.72) and the South Asian summer monsoon precipitation (r = −0.66). South Asian summer monsoon precipitation and ENSO are the main factors controlling this common signal of tree-ring δ18O across MA. PC1 of tree-ring δ18O chronologies in MA also depicted a negative (positive) correlation with the Atlantic Multidecadal Oscillation (Pacific Decadal Oscillation), indicating the large-scale circulation influences. After removing the large-scale circulation influences on tree-ring δ18O chronologies, however, the residual tree-ring δ18O chronologies exhibit negative correlations with the regional hydroclimate, highlighting the role local hydroclimate on the individual tree-ring δ18O variations.

DOI： 10.1016/j.quascirev.2021.107156

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Scopus

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Last author   Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.5026/jgeography.128.49

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

DOI： 10.1093/treephys/tpy068

PubMed

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

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

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Last author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1038/ncomms15386

PubMed

Publisher：Journal of Forestry Research  

Tree-ring width (RW), density, elemental composition, and stable carbon and oxygen isotope (δ13C, δ18O) are widely used as proxies to assess climate change, ecology, and environmental pollution; however, a specific pretreatment has been needed for each proxy. Here, we developed a method by which each proxy can be measured in the same sample. First, the sample is polished for ring width measurement. After obtaining the ring width data, the sample is cut to form a 1-mm-thick wood plate. The sample is then mounted in a vertical sample holder, and gradually scanned by an X-ray beam. Simultaneously, the count rates of the fluorescent photons of elements (for chemical characterization) and a radiographic grayscale image (for wood density) are obtained, i.e. the density and the element content are obtained. Then, cellulose is isolated from the 1-mm wood plate by removal of lignin, and hemicellulose. After producing this cellulose plate, cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope (δ13C, δ18O) analysis. Based on this method, RW, density, elemental composition, δ13C, and δ18O can be measured from the same sample, which reduces sample amount and treatment time, and is helpful for multi-proxy comparison and combination research.

DOI： 10.1007/s11676-024-01707-9

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

DOI： 10.1016/j.quascirev.2024.108861

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

DOI： 10.1017/RDC.2024.55

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Scopus

Language：English  

DOI： 10.1017/RDC.2023.50

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Scopus

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

DOI： 10.1186/s40562-023-00282-x

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Language：English   Publishing type：Research paper (conference, symposium, etc.)   Publisher：THE JAPANESE FORESTRY SOCIETY  

<p>[in Japanese]</p>

DOI： 10.11519/jfsc.134.0_503

CiNii Research

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1017/RDC.2023.14

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Scopus

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

DOI： 10.1038/s41612-023-00341-2

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Scopus

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

DOI： 10.1016/j.scitotenv.2022.159437

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PubMed

Authorship：Last author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1029/2022JD037260

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Scopus

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

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Publisher：Journal of Hydrology  

The East Asian summer monsoon (EASM) and Indian summer monsoon (ISM) are two interactive climate systems dominating the moisture variability of Monsoon Asia. However, ISM-EASM interactions and their effects on regional moisture dynamics remain unclear. This study investigated the spatiotemporal characteristics of monsoon-related hydroclimate variability by establishing a new tree-ring oxygen isotope ratio (δ18Otree) network of eight δ18Otree records covering the last 150 years in southern China, which differs from previous studies that used data from individual sites. The δ18Otree chronologies were found to be sensitive to regional hydroclimatic changes during the monsoon season. The δ18Otree network indicated an east–west clustering pattern in the ISM-EASM transitional zone, which demonstrates an asynchrony in δ18Otree variability in the west and east of this region. Regional variability of the west and east δ18Otree modes reflected the different moisture signals, as indicated by their significant correlations with modern observations and paleo-δ18O records in disparate upstream regions of moisture transport (the Indochina Peninsula and Southeast China). This finding was confirmed by the east–west distinct pattern of spatial isotopic depletion of monsoon rainfall that originates from coastal areas of tropical oceans (Bay of Bengal and South China Sea) to the study area, as well as the consistent present-day pattern of atmospheric vapor transport during the monsoon season. In addition, the west and east modes exhibited stronger associations with ISM variability, whereas the east–west δ18Otree gradient captured the EASM-related hydroclimatic signal, suggesting that summer moisture variability in the ISM-EASM transitional zone was regulated more by ISM than by EASM during the last 150 years. The relationships between δ18Otree and large-scale ocean–atmosphere interaction modes revealed that the El Niño-Southern Oscillation (ENSO) dominantly modulates δ18Otree variability across southern China.

DOI： 10.1016/j.jhydrol.2022.128484

Scopus

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

DOI： 10.1029/2022WR031953

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Scopus

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (other academic)  

Language：Japanese   Publisher：Japan Science Support Foundation  

DOI： 10.5363/tits.27.2_31

CiNii Research

CiNii Research

Language：Japanese   Publisher：水文・水資源学会  

<p>樹木年輪セルロース酸素同位体比は過去の気候変動をよく反映していることが確かめられている。近年では，年輪に含まれる酸素同位体比の測定手法の発達により，より純粋な気象因子との結びつきを検討できる可能性が期待されている．一方で樹木年輪の既往研究の多くは１年輪の測定により行われており，１年の時間分解能を持つデータが一般的である．そのため気候変動や海洋変動が日本陸域へ及ぼす季節ごとの影響を検討することが困難な場合がある．</p><p>本研究では１年輪を年層内分割し得られた酸素同位体比データを用いて，気象代替データの時間分解能向上と年輪から考えられる海洋変動による陸域での季節変動について検討する．奄美大島の樹齢２００年のリュウキュウマツ３個体を対象として、年輪を形成するセルロースの抽出を行う。セルロース試料から測定サンプルを切り分ける際に、各年輪を成長方向へ分割する。測定データを用いて海洋変動が南西諸島陸域にもたらす影響を検討するために複数の海洋因子との相関分析を行う．</p><p>結果としてENSO、PDOとの強い関連は得られなかった。一部年層内の成長期の終わり（11月頃）に相当する部分の酸素同位体比とENSOの間で正相関が得られた。ラニーニャ発生時期に奄美周辺の11月頃の日照時間が低下することが、同位体比変動に現れたと考えられる。一方でNPGOに関しては、1年遅いNPGOと梅雨入りに相当する部分の酸素同位体比、４年先行したNPGOと年層内の成長期の始まり（4月頃）に相当する部分の酸素同位体比との正相関が得られた。先行研究で東北地方を対象とした年輪同位体比と初夏の報告があり、東北地方のみならず南西諸島にも関連した指標であると考えられる。以上のように年輪の年層内分割は季節性の代替データを提供するとともに、大規模な海洋変動が陸域へ及ぼす関係を検討するのに有効な手段になると考えられる。</p>

DOI： 10.11520/jshwr.35.0_115

CiNii Research

CiNii Research

CiNii Research

CiNii Research

Language：Japanese   Publisher：日本科学者会議  

DOI： 10.60233/jjsci.57.1_46

CiNii Research

CiNii Research

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

Owing to the increased need to assess global forest behavior under changing climatic conditions within a long-term context, spatial coherence in tree-ring records is of widespread interest. Spatial networks of tree growth have been widely discussed from regional to global scales, but few studies have reported stable oxygen isotopes in networks of tree rings (δ18Otree), thus impeding a comprehensive hydroclimatic interpretation of δ18Otree records over large spatial scales, i.e., isoscapes. In this study, a network of four annually resolved δ18Otree chronologies (1805–2016) was developed for Southwest China, the transitional zone of the Asian summer monsoon, to test spatial coherence in δ18Otree variations and to explore the climatic factors driving synchrony at different spatial scales. The quantitative analyses show that the four chronologies exhibit consistent annual variations, with the first principal component (PC1) accounting for 70% of the total variance, which uniformly respond to local relative humidity (RH) and precipitation δ18O during the monsoon season. This confirms the spatial coherence in δ18Otree records. Furthermore, significant inter-site correlations of local RH and precipitation δ18O are also detected, revealing that it is the regionally homogeneous year-to-year variations in the hydroclimate that should be responsible for spatial coherence. For a larger spatial perspective, spatial correlation analyses reveal that the most prominent correlations between δ18Otree and hydroclimate fields occur in the Indochina Peninsula, in which δ18Otree changes are synchronized with those in Southwest China and the synchrony temporally varies with the Indian summer monsoon (ISM) intensity, indicating that coherent δ18Otree variations are linked to ISM-related moisture transport. In addition, δ18Otree records have shown strong in-phase relationships with the natural variabilities of the ISM and El Niño-Southern Oscillation (ENSO) across interannual and interdecadal timescales over the last 150 years, suggesting that spatial coherence in δ18Otree records can be utilized to reflect the long-term history of large-scale atmospheric circulation.

DOI： 10.1016/j.agrformet.2021.108687

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

<p>A seamless reconstruction of summer climate variation for all periodicities has been carried out in central Japan by integrating tree-ring oxygen and hydrogen isotopes. By decomposing the time series, I have found that the amplitude of multi-decadal variations is enhanced at every 400 years, inducing societal regime shifts over East Asia. I will discuss its natural and human scientific meanings referring the results of an inter-disciplinary research project in Research Institute for Humanity and Nature.</p>

DOI： 10.14862/geochemproc.68.0_53

CiNii Research

Language：Japanese   Publisher：Quaternary Research (United States)  

We present a long-term seasonal tree ring cellulose oxygen isotope (δ18Oc) time series created by analyzing four segments (S1, S2, S3, and S4) per year during the period of 1951-2009 from southeastern Tibetan Plateau. This intraseasonal δ18Oc reveals the onset and mature phase of the summer monsoon precipitation in this region. Analysis indicates that the δ18Oc of S1 has the strongest correlation with precipitation during the regional monsoon onset (29-33 pentads, May 21-June 10, r =-0.69), and the δ18Oc values for S2, S3, and S4 correlate strongly with June, July, and August precipitation, respectively. Combined δ18Oc of S2, S3, and S4 shows the most robust correlation (r =-0.82) with the mature-phase monsoon precipitation (June-July-August, JJA), passing rigorous statistical tests for calibration and verification in dendroclimatology. These results demonstrate the feasibility in using long-term intraseasonal δ18Oc to reconstruct the Asian summer monsoon's intraseasonal variations.

DOI： 10.1017/qua.2020.28

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Atmosphere  

We present the first Greenlandic tree ring oxygen isotope record (δ18OGTR), derived from four birch trees collected from the Qinguadalen Valley in southwestern Greenland in 1999. Our δ18O record spans from 1950–1999 and is significantly and positively correlated with winter ice core δ18O from southern Greenland. δ18OGTR records are positively correlated with southwestern Greenland January–August mean temperatures. North Atlantic Oscillation (NAO) reconstructions have been developed from a variety of proxies, but never with Greenlandic tree rings, and our δ18OGTR record is significantly correlated with NAO (r = −0.64), and spatial correlations with sea-level pressure indicate a classic NAO pressure seesaw pattern. These results may facilitate a longer NAO reconstruction based on long time series of tree ring δ18O records from Greenland, provided that subfossil wood can be found in areas vacated by melting glaciers.

DOI： 10.3390/atmos12010039

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

DOI： https://doi.org/10.11475/sabo.73.5_3

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Science of the Total Environment  

Global warming has had an unprecedented impact on environmental changes and thus human life in mid-high latitude regions. As one of the areas most affected by global warming, Northeast China has suffered from a series of ecological crises, including warming-induced water deficits, permafrost thaw, and extended growing seasons. The change in annual average temperature (annual T) variations in Northeast China since the Industrial Revolution are still not fully understood, mainly because of the lack of long-term instrumental data and high-resolution annual T reconstructions. Here, we present the first annual T reconstruction (r = −0.683, p <.001, n = 60) for 1818–2012 in Northeast China, which may also be the first temperature reconstruction based on tree-ring δ18O in China. The reconstruction is significantly related to temperature variations over mid-high latitude Eurasia and agree (p <.01) with several long-term hydroclimatic reconstructions in the surrounding area. When the internal variability in the reconstruction was high, the decadal to multidecadal cycles were significant. Further analysis found that the reconstruction was mainly affected by the East Asian Summer Monsoon (EASM) and North Atlantic Oscillation (NAO). The reconstruction was significantly negatively correlated with several time series of annual T in the Northern Hemisphere, which showed that there is a substantial difference in annual T between Northeast China and other regions of the Northern Hemisphere. The difference mainly existed before the 1950s. From the 1850s to the 1950s, the annual T in Northeast China decreased slightly. However, extreme warming began in the 1950s in Northeast China, and this warming has been unprecedented during the past two centuries. If the warming trend since the 1950s continues, then it will lead to devastating disasters to forest and permafrost ecosystems in Northeast China.

DOI： 10.1016/j.scitotenv.2020.141432

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Scopus

PubMed

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Journal of Hydrology  

The Asian Summer Monsoon system (ASM) affects a large population in the monsoonal Asia. Previous studies have thoroughly discussed the temporally unstable response of tree-ring oxygen isotope (δ18O) to the regional climate variables and ocean–atmosphere interaction modes, however, the response to the ASM remains ambiguous. In this study, an annually resolved tree-ring δ18O chronology is developed from eastern Yunnan-Guizhou Plateau, in the transitional zone of the ASM. Based on the results from response analyses, the climatic controls of tree-ring δ18O is considered to be the moisture-related variables of the monsoon season. Spatial correlations suggest that in the study area, the water vapor is mainly originated from the Bay of Bengal and transported by the Indian Summer Monsoon (ISM). Furthermore, the temporal stability in relationships between the tree-ring δ18O and the ISM variability are explored. Our findings suggest that on interannual to decadal timescales, the tree-ring δ18O is significantly anti-correlated, but temporally unstable with respect to the ISM. The strength of interannual relationship is affected by the ISM intensity, which is modulated by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) variability. Moreover, the strength of decadal relationship is associated with the phase shift of the Pacific Decadal Oscillation (PDO). Additionally, the decreasing trend of tree-ring δ18O after the late 1970 s that diverges from the simultaneous normal level of the ISM is caused by the isotopically-depleted trend in upstream precipitation of the moisture source. The opposite patterns of correlations between the tree-ring δ18O and the ENSO and IOD in recent decades demonstrate that the regional hydroclimate in the study region has been undergoing significant secular variations that are characterised by an increasing effect of the IOD and a decreasing effect of the ENSO. The findings from this study further improve our understanding of the tree-ring δ18O response to the ASM, at multi-time scales, and shed light on the impact of the ASM on regional hydroclimate variability, across the transitional zone of the ASM.

DOI： 10.1016/j.jhydrol.2020.125522

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Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Journal of Wood Science  

The current study was initiated to test the synchronizations of tree-ring δ18O (hereafter δ18OTR) time series within and between tree species and provinces, which are about 144 km apart from each other in Korea. For the test, a 50-year δ18OTR time series (1966–2015) was developed using four trees from each tree species which are Pinus densiflora and Quercus mongolica from Songnisan National Park and Taxus cuspidata, Pinus koraiensis, Abies koreana, and Quercus mongolica from Jirisan National Park. Their synchronizations were evaluated using t-value, Gleichläufigkeit (Glk), and Expressed Population Signal (EPS). The mean t-values and Glk scores within the tree species ranged 5.2–11.2 (p < 0.05) and 69–83%, and between the tree species ranged 6.1–13.2 (p < 0.05) and 73–81%, respectively. The mean t-value and Glk score between the regions were 4.3 (p < 0.05) and 72%, respectively. Furthermore, the EPS showed higher than 0.85, which is the generally accepted threshold value in dendrochronology, except for Q. mongolica at Songnisan National Park for which the value is 0.83 calculated by only two δ18OTR time series. Based on the statistical results, we concluded that a δ18OTR chronology established using more than four trees could serve as a promising reference for dating an undated wood without considering the tree species, as well as for research on climate in the past.

DOI： 10.1186/s10086-020-01901-3

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：COPERNICUS GESELLSCHAFT MBH  

Knowledge of past variations in sea-ice extent is crucial for understanding the relationship between climate change and changes in sea ice. Diatom assemblages could be applied as a proxy for paleo-sea-ice extent; this requires accurate information on the modern species that are indicative of sea ice. Scanning electron microscope observations were performed on modern diatom assemblages in sea ice, sinking particles, and surface sediments in the Sea of Okhotsk. A sea-ice sample was collected in the southwestern Sea of Okhotsk near Hokkaido island in February 2013. Fragilariopsis cylindrus was the dominant diatom species in the sea-ice sample, accounting for 87% of the total diatom assemblage. Time-series sediment traps were deployed during 1998-2000 at two stations, M4 and M6, off Sakhalin island. Total diatom fluxes ranged from 10(5) to 10(8) valves m(-2) d(-1) with noticeable seasonality. During the sea-ice covering period, the total diatom flux decreased by 1 or 2 orders of magnitude. The highest diatom fluxes were observed in spring and summer. The diatom species composition in sinking particles also showed pronounced seasonal changes. During summer and fall, the Shionodiscus trifultus group and Neodenticula seminae were the major diatom taxa. During the sea-ice covering period, Fragilariopsis cylindrus and Bacterosira bathyomphala resting spores were abundant. Both the sea-ice-related species showed similar flux patterns except for the spring bloom after sea-ice retreat: F. cylindrus fluxes exhibited pronounced spring bloom peaks of 10(8) valves m(-2) d(-1); in contrast, the fluxes of Bacterosira bathyomphala resting spores during the spring bloom were 1 order of magnitude lower than those of F. cylindrus. Surface-sediment core XP98-MC4 was obtained near station M6 sediment-trap site off Sakhalin island. The relative abundance of Fragilariopsis cylindrus in the surface-sediment diatom assemblage was only 6.4 %, markedly lower than that in the sediment-trap samples (43.4 %). In the surface sediment, the relative abundances of diatom taxa with heavily silicified valves such as B. bathyomphala resting spores, Shionodiscus variantius, and Thalassionema nitzschioides were greater than their relative abundances in sinking particles.

DOI： 10.5194/jm-39-77-2020

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Scopus

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

DOI： 10.1038/s41598-020-66001-0

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Scopus

PubMed

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

DOI： 10.1016/j.agrformet.2020.107929

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Scopus

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

DOI： 10.1007/s00704-019-03036-y

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Authorship：Lead author   Language：Japanese  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.5194/cp-2020-6

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

DOI： 10.1016/j.scitotenv.2019.06.268

PubMed

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

DOI： 10.1016/j.dendro.2019.125626

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

DOI： 10.1007/s00484-017-1365-6

PubMed

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

DOI： 10.1016/j.scitotenv.2019.01.186

PubMed

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

DOI： 10.1029/2018GL081458

CiNii Research

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG  

The oxygen isotopic composition (delta O-18) of tree-ring cellulose has been recognized as a powerful tool for dendroclimatological and dendrochronological investigations in Asia. Only a few studies of cellulose delta O-18 so far published, however, have been conducted in Indonesia, and the spatial coherence of cellulose delta O-18 has yet to be clarified. In this study we measured cellulose delta O-18 of teak (Tectona grandis) collected from four sites on Java Island to evaluate the similarity between the different teak delta O-18 values and the potential for using teak delta O-18 both as a climate proxy and as a tool for cross-dating. Cellulose delta O-18 time series of Javanese teaks were found to be significantly correlated in all of the comparisons between sites, even between sites separated by a distance as great as 400 km. While significant correlations did not appear in the ring width data between our samples (expressed population signal (EPS) = 0.64; Rbar = 0.23; sample depth = 10), they were found between the cellulose delta O-18 values (EPS = 0.89; Rbar = 0.58; sample depth = 10). These results suggest that teak delta O-18 variations have higher spatial coherence and might be a useful tool for cross-dating. A significant negative correlation was observed between cellulose delta O-18 and the relative humidity/precipitation during the rainy season, indicating that the cellulose delta O-18 of Javanese teak is an effective proxy for relative humidity/precipitation during the rainy season. Cellulose delta O-18 was found to be positively correlated with precipitation during the dry season preceding the growing season, whereas it showed no correlations with the temperature and Palmer Drought Severity Index (PDSI), the key constraints of delta O-18 on the Indochina Peninsula.

DOI： 10.1016/j.dendro.2018.09.010

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

DOI： doi.org/10.1007/s00382-018-4515-6

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

DOI： 10.1080/10256016.2018.1495203

PubMed

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

DOI： doi.org/10.1002/joc.5859

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

DOI： doi.org/10.5194/cp-14-653-2018

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

DOI： doi.org/10.1007/s00382-018-4212-5

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Authorship：Last author   Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

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

CiNii Research

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

DOI： doi.org/10.1186/s40562-017-0095-2

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

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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

DOI： doi.org/10.1080/16000889.2017.1391663

Authorship：Lead author   Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

<p></p>

DOI： 10.14862/geochemproc.64.0_15

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

DOI： doi.org/10.1016/j.gloplacha.2017.08.009

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

DOI： doi.org/10.1016/j.quaint.2017.06.020

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

DOI： 10.1016/j.quaint.2015.03.038

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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

DOI： doi: 10.1002/2016JD025463

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Authorship：Lead author   Language：Japanese  

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

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

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

DOI： 10.1002/grl.50113

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

DOI： doi:10.1002/jgrd.50664

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

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

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

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

DOI： 10.1007/s00704-013-0858-4

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

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

DOI： 10.1002/gbc.20088

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

DOI： 10.1007/s00382-012-1611-x

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

DOI： 10.1029/2012JD017749

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

DOI： 10.1016/j.chemgeo.2011.01.004

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

DOI： 10.1029/2011JD015987

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

DOI： 10.1029/2011JD016694

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

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

DOI： 10.1029/2011GL048507

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

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

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

DOI： 10.1029/2010JD014602

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

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

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

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

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

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

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

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

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

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

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

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

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

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

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

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

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

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

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

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

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

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

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese  

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

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

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

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

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

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

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

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

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese  

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

Authorship：Lead author   Language：Japanese  

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

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

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：Japanese  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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

Language：Japanese Book type：Scholarly book

CiNii Books

Language：Japanese Book type：Scholarly book

CiNii Books

Language：Japanese Book type：Scholarly book

CiNii Books

Language：Japanese Book type：Scholarly book

CiNii Books

Total pages：528   Responsible for pages：111-124   Language：Japanese Book type：Scholarly book

Total pages：284   Responsible for pages：53-65   Language：Japanese Book type：General book, introductory book for general audience

Total pages：284   Responsible for pages：104-111   Language：Japanese Book type：General book, introductory book for general audience

Language：Japanese Book type：General book, introductory book for general audience

Total pages：176   Responsible for pages：6-34   Language：Japanese Book type：Scholarly book

Language：Japanese Book type：Scholarly book

Language：Japanese

Language：Japanese

Event date： 2023.12

Language：English  

Venue：Leipzig University, Leipzig, Germany   Country：Germany  

Event date： 2023.10

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：名古屋大学環境学研究科レクチャーホール   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：早稲田大学・所沢キャンパス   Country：Japan  

Event date： 2023.7

Language：English   Presentation type：Symposium, workshop panel (nominated)  

Venue：Sapporo   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：早稲田エクステンションセンター（オンライン）   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：島根   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：早稲田エクステンションセンター（オンライン）   Country：Japan  

Event date： 2023.5

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：早稲田エクステンションセンター（オンライン）   Country：Japan  

Event date： 2023.5

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：早稲田エクステンションセンター（オンライン）   Country：Japan  

Event date： 2023.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Vienna   Country：Austria  

Event date： 2023.4

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：早稲田エクステンションセンター（オンライン）   Country：Japan  

Event date： 2023.4

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：早稲田エクステンションセンター（オンライン）   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：名古屋大学ES総合館（名古屋）   Country：Japan  

Event date： 2023.2

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：ナディアパーク（名古屋）   Country：Japan  

Event date： 2023.1

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：ウィンクあいち（名古屋）   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：京都   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：名古屋大学減災館1階減災ホール   Country：Japan  

Event date： 2022.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京大学・大気海洋研究所（柏キャンパス）   Country：Japan  

Event date： 2022.10

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：名古屋   Country：Japan  

Event date： 2022.10

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：東京大学・弥生講堂・一条ホール   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：東京   Country：Japan  

Event date： 2022.6

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：札幌   Country：Japan  

Event date： 2022.4

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Asian Dendrochronological Association   Country：China  

Event date： 2022.3

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：岐阜県瑞浪市   Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：大阪（オンライン）   Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：島根（オンライン）   Country：Japan  

Event date： 2022.2

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：仙台（オンライン）   Country：Japan  

Event date： 2022.2

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：オンライン   Country：Japan  

Event date： 2021.12

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：名古屋   Country：Japan  

Event date： 2021.12

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：東京   Country：Japan  

Event date： 2021.12

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：弘前（オンライン）   Country：Japan  

Event date： 2021.8

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：東京（オンライン）   Country：Japan  

Event date： 2021.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Oline   Country：Japan  

Event date： 2021.5

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：大阪（オンライン）   Country：Japan  

Event date： 2021.4

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：京都（オンライン）   Country：Japan  

Event date： 2021.3

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.2

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Kyoto   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2020.7

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：オンライン   Country：Japan  

Event date： 2019.11

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Lucknow, India   Country：India  

Event date： 2019.11

Language：English   Presentation type：Poster presentation  

Venue：Lucknow, India   Country：India  

Event date： 2019.10

Language：Japanese   Presentation type：Oral presentation (keynote)  

Venue：岡山大学   Country：Japan  

Event date： 2019.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Xi'an, China   Country：China  

Event date： 2019.5

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：幕張メッセ   Country：Japan  

Event date： 2010.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2010.8

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2010.8

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2010.6

Language：English   Presentation type：Oral presentation (general)  

Event date： 2010.6

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2010.1

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2009.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2009.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2009.7

Language：English   Presentation type：Poster presentation  

Event date： 2009.7

Language：English   Presentation type：Oral presentation (general)  

Event date： 2009.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2009.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2009.5

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2009.3

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2009.2

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2009.1

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.12

Language：English   Presentation type：Poster presentation  

Event date： 2008.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.9

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2008.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.8

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.8

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2008.7

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.6

Language：English   Presentation type：Oral presentation (invited, special)  

Event date： 2008.6

Language：English   Presentation type：Oral presentation (general)  

Event date： 2008.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2008.5

Language：English   Presentation type：Oral presentation (invited, special)  

Event date： 2008.5

Language：English   Presentation type：Poster presentation  

Audience： General

Type：Lecture

Audience： General

Type：Lecture

Audience： General

Type：Lecture

Audience： General

Type：Science cafe

Audience： General

Type：Lecture