Kenji Tanaka

Dr. Kenji Tanaka


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 February 2018 in Water
Verified
Journal Article
Open access
PDF file
MHMaochuan Hu
Maochuan Hu
XZXingqi Zhang
Xingqi Zhang
YSYim Ling Siu
Yim Ling Siu
YLYU LI
YU LI
KTKenji Tanaka
Kenji Tanaka
YXYoupeng Xu
Youpeng Xu
It is important to evaluate the effectiveness of permeable pavements on flood mitigation at different spatial scales for their effective application, for example, sponge city construction in China. This study evaluated the effectiveness of three types of permeable pavements (i.e., permeable asphalts (PA), permeable concretes (PC), and permeable interlocking concrete pavers (PICP)) on flood mitigation at a community scale in China using a hydrological model. In addition, the effects of clogging and initial water content in permeable pavements on flood mitigation performance were assessed. The results indicated that in 12 scenarios, permeable pavements reduced total surface runoff by 1–40% and peak flow by 7–43%, respectively. The hydrological performance of permeable pavements was limited by clogging and initial water content. Clogging resulted in the effectiveness on total surface runoff reduction and peak flow reduction being decreased by 62–92% and 37–65%, respectively. By increasing initial water content at the beginning of the simulation, the effectiveness of total runoff reduction and peak flow reduction decreased by 57–85% and 37–67%, respectively. Overall, among the three types of permeable pavements, PC without clogging had the best performance in terms of flood mitigation, and PICP was the least prone to being clogged. Our findings demonstrate that both the type and the maintenance of permeable pavements have significant effects on their performance in the flood mitigation.

27 August 2019 in Water
Verified
Journal Article
Open access
PDF file
MHMaochuan Hu
Maochuan Hu
TSTakahiro Sayama
Takahiro Sayama
Sophal TrySophal Try
Sophal Try
KTKaoru Takara
Kaoru Takara
KTKenji Tanaka
Kenji Tanaka
Understanding long-term trends in hydrological and climatic variables is of high significance for sustainable water resource management. This study focuses on the annual and seasonal trends in precipitation, temperature, potential evapotranspiration, and river discharge over the Kamo River basin from the hydrological years 1962 to 2017. Homogeneity was examined by Levene’s test. The Mann–Kendall and a modified Mann–Kendall test as well as Sen’s slope estimator were used to analyze significant trends (p < 0.05) in a time series with and without serial correlation and their magnitudes. The results indicate that potential evapotranspiration calculated by the Penman–Monteith equation was highly related to temperature, and significantly increased in the annual and summer series. Annual river discharge significantly decreased by 0.09 m3/s. No significant trend was found at the seasonal scale. Annual, autumn, and winter precipitation at Kumogahata station significantly increased, while no significant trend was found at Kyoto station. Precipitation was least affected by the modified Mann–Kendall test. Other variables were relatively highly autocorrelated. The modified Mann–Kendall test with a full autocorrelation structure improved the accuracy of trend analysis. Furthermore, this study provides information for decision makers to take proactive measures for sustainable water management.

1 June 2013 in Journal of Disaster Research
Verified
Journal Article
Closed access
SKShunji Kotsuki
Shunji Kotsuki
KTKenji Tanaka
Kenji Tanaka
Welcome to the official website of Journal of Disaster Research.

18 September 2020 in Climate
Verified
Journal Article
Open access
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Bakhtiyar Makhamatjanovich KholmatjanovBakhtiyar Makhamatjanovich Kholmatjanov
Bakhtiyar Makhamatjanovich Kholmatjanov
YPYuriy V. Petrov
Yuriy V. Petrov
TKTemur Khujanazarov
Temur Khujanazarov
Nigora SulaymonovaNigora Sulaymonova
Nigora Sulaymonova
FAFarrukh I. Abdikulov
Farrukh I. Abdikulov
KTKenji Tanaka
Kenji Tanaka
Climate change and shrinking of the Aral Sea have significantly affected the region’s temperature variations. Observed interannual changes in Uzbekistan’s air temperature compared to the duration of synoptic weather types (SWT) in Middle Asia were analyzed. Nonparametric Mann–Kendall statistical test and climate trends coefficients were used to identify trend characteristics of observed temperature from 1961–2016 to the baseline period of 1961–1990. The results showed increasing temperature trends average to 1 °C in warm and cold half years over Uzbekistan. The 1991–2016 decadal temperature trend ranged from 0.25 °C/decade in the northwest to 0.52 °C/decade in the center, especially pronounced in the oasis and Aral Sea zones. There were also significant changes in the structure of regional SWT. The main difference in the structure of SWT in Middle Asia relative to the baseline period was expressed in a decrease of cold mass invasion duration from 113.4 to 76.1 days and an increase in low-gradient baric field duration from 65.8 to 134.6 days. The process of anthropogenic warming, which began in Uzbekistan in the 1960s of the twentieth century, has accelerated from the mid-1970s with a higher mean annual air temperature than the baseline period’s climate normals (1961–1990) and is associated with changes in the regional SWT over Middle Asia.

1 January 2022 in Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering)
Verified
Journal Article
Open access
PDF file
ATAkihide Tasaka
Akihide Tasaka
KTKenji Tanaka
Kenji Tanaka
STShigenobu Tanaka
Shigenobu Tanaka
気象研究所のRCP8.5シナリオに沿った気候モデルMRI-AGCM3.2Sの150年連続ランを用いて,日本の水資源量の長期変化を予測した.本研究では,日単位の水需給量を比較することで,気候変動による降雨の時空間分布の変化や連続した無降水・少雨の増加の影響により,将来気候下で,日本のどの地域で水資源量が逼迫するのかを評価した.その結果,特に水資源量の逼迫が予測される地域は十勝平野周辺と千葉県から福島県にかけての太平洋側,松本盆地周辺,大阪府周辺,瀬戸内海沿岸,そして九州沖縄地方であることが明らかになった.さらに,東北地方日本海側や九州地方では,年水資源賦存量(降水量-蒸発散量)は増加するものの,増加する時期の水需給バランスによっては増加分の水資源を利用できず,むしろ水資源の利用が逼迫する地域が確認された.

12 December 2018
Verified
Book Chapter
Closed access
PDF file
KTKenji Tanaka
Kenji Tanaka
YFYoichi Fujihara
Yoichi Fujihara
FTFatih Topaloğlu
Fatih Topaloğlu
Slobodan SimonovicSlobodan Simonovic
Slobodan Simonovic
TKToshiharu Kojiri
Toshiharu Kojiri