2021/05/15 更新

写真a

ウイタカ アンドリュー チャールズ
WHITAKER Andrew Charles
WHITAKER Andrew
所属
教育研究院 自然科学系 農学系列 准教授
農学部 准教授
自然科学研究科 環境科学専攻 流域環境学 准教授
職名
准教授
外部リンク

学位

  • Ph.D.(Forest Hydrology) ( 1997年5月   モンタナ大学 )

研究キーワード

  • Forest Influences

  • Land Use and Climate Change

  • Snow Hydrology

  • Sediment Transport

  • Hydrology

研究分野

  • 社会基盤(土木・建築・防災) / 水工学

  • ライフサイエンス / 森林科学

  • 自然科学一般 / 大気水圏科学

経歴(researchmap)

  • Assistant Professor, Faculty of Agriculture, Niigata University

    2007年 - 現在

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  • Assistant Professor, Graduate School of Science and Technology, Niigata University

    1999年 - 2007年

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  • Research Associate, Faculty of Forestry, University of British Columbia

    1997年 - 1999年

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経歴

  • 新潟大学   自然科学研究科 環境科学専攻 流域環境学   准教授

    2012年8月 - 現在

  • 新潟大学   生産環境科学科   准教授

    2012年8月 - 2017年3月

  • 新潟大学   生産環境科学科   助教

    2007年4月 - 2012年7月

  • 新潟大学   自然科学研究科   助手

    1999年6月 - 2007年3月

学歴

  • モンタナ大学大学院   森林水文学

    - 1997年

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    国名: 日本国

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  • University of Montana   School of Forestry   Forest Hydrology

    - 1997年

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    国名: アメリカ合衆国

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  • University of Newcastle-Upon-Tyne   Department of Civil Engineering   Engineering Hydrology

    - 1992年

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    国名: グレートブリテン・北アイルランド連合王国(英国)

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  • University of Bristol   Faculty of Science   Physical Geography

    - 1991年

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    国名: グレートブリテン・北アイルランド連合王国(英国)

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所属学協会

  • International Association of Hydrological Sciences

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  • Japanese Geomorphological Union

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  • American Geophysical Union

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  • American Geophysical Union (AGU)

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  • International Association of Hydrological Sciences (IAHS)

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MISC

  • Coarse bed load transport in an alluvial gravel bed stream, Dupuyer Creek, Montana

    Andrew C. Whitaker, Donald F. Potts

    EARTH SURFACE PROCESSES AND LANDFORMS32 ( 13 ) 1984 - 2004   2007年11月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    Coarse bed load was sampled in a gravel/cobble bed stream during two major floods in the snowmelt runoff season. The channel is characterized by high rates of bank erosion and, therefore, high rates of sediment supply and bed load flux. Peak discharge reached four times bank-full, and bed load was sampled at flows 0.7-1.7 times bank-full. A large aperture bed load sampler (1 m by 0.45 m) captured the largest particles in motion, and specifically targeted the coarse bed load size distribution by using a relatively large mesh (32 mm or D-25 of streambed surface size distribution). Bed load flux was highly variable, with a peak value of 0.85 kg/s/m for the coarse fraction above 38 mm. Bed load size distribution and maximum particle size was related to flow strength. Entrainment was size selective for particles D-70. and larger (88-155 mm), while particles in the range D-30-D-70 (35-88 mm) ceased to move at essentially the same flow. Bed load flux was size selective in that coarse fractions of the streambed surface were under-represented in or absent from the bed load. Painted tracer particles revealed that the streambed surface in the riffles could remain stable even during high rates of bed load transport. These observations suggest that a large proportion of bed load sediments was sourced from outside the riffles. Repeat surveys confirmed major scour and fill in pools (up to 0.75 m), and bank erosion (>2 m), which together contributed large volumes of sediment to the bed load. Copyright (c) 2007 John Wiley & Sons, Ltd.

    DOI: 10.1002/esp.1512

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  • Analysis of flow competence in an alluvial gravel bed stream, Dupuyer Creek, Montana

    Andrew C. Whitaker, Donald F. Potts

    WATER RESOURCES RESEARCH43 ( 7 )   2007年7月

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    記述言語:英語   出版者・発行元:AMER GEOPHYSICAL UNION  

    Critical shear stress and unit discharge flow competence models were tested against coarse bed load data from Dupuyer Creek, Montana, United States. Maximum particle sizes sampled (Dmax) and D-50 to D-90 percentiles in the bed load grain size distribution were well correlated with both shear stress and unit discharge. Bed load grain sizes became coarser with increasing flow strength. For the D-max curve, Shields dimensionless parameter for the surface D-50 was estimated at 0.044, and the exponent for relative particle size (D-i/ D-50) was - 0.59. In the unit discharge criterion the critical flow to entrain the surface D50 was poorly predicted. Flow competence relationships based on D-max are prone to the influence of outliers and sample mass variability. The mean of the three largest particles, D-max ( 3), is more sensitive to changes in flow strength than the D-50 to D-90 bed load grain sizes, and may represent a good compromise.

    DOI: 10.1029/2006WR005289

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  • Fluctuations of the carbon dioxide concentration in the soil air influenced by hydrological characteristics in a snowy mountain area

    Tsukada, Sugiyama, Whitaker, Zhang

    Trans. JSIDRE244   263 - 270   2006年

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  • Periodic variability of precipitation characteristics in the region of Niigata Prefecture

    Zhang, Tanaka, Sugiyama, Whitaker

    Trans. JSIDRE246   115 - 122   2006年

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  • Seasonal snowpack dynamics and runoff in a cool temperate forest: lysimeter experiment in Niigata, Japan

    AC Whitaker, H Sugiyama

    HYDROLOGICAL PROCESSES19 ( 20 ) 4179 - 4200   2005年12月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    Seasonal snowpack dynamics are described through field measurements under contrasting canopy conditions for a mountainous catchment in the Japan Sea region. Microclimatic data, snow accumulation, albedo and lysimeter runoff are given through the complete winter season 2002-03 in (1) a mature cedar stand, (2) a larch stand, and (3) a regenerating cedar stand or opening. The accumulation and melt of seasonal snowpack strongly influences streamflow runoff during December to May, including winter baseflow, mid-winter melt, rain on snow, and diurnal peaks driven by radiation melt in spring. Lysimeter runoff at all sites is characterized by constant ground melt of 0.8-1.0 mm day(-1). Rapid response to mid-winter melt or rainfall shows that the snowpack remains in a ripe or near-ripe condition throughout the snow-cover season. Hourly and daily lysimeter discharge was greatest during rain on snow (e.g. 7 mm h(-1) and 53 mm day(-1) on 17 December) with the majority of runoff due to rainfall passing through the snowpack as opposed to snowmelt. For both rain-on-snow and radiation melt events lysimeter discharge was generally greatest at the open site, although there were exceptions such as during interception melt events. During radiation melt instantaneous discharge was up to 4.0 times greater in the opening compared with the mature cedar, and 48 h discharge was up to 2.5 times greater. Perhaps characteristic of maritime climates, forest interception melt is shown to be important in addition to sublimation in reducing snow accumulation beneath dense canopies. While sublimation represents a loss from the catchment water balance, interception melt percolates through the snowpack and contributes to soil moisture during the winter season. Strong differences in microclimate and snowpack albedo persisted between cedar. larch and open sites, and it is suggested further work is needed to account for this in hydrological simulation models. Copyright (c) 2005 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.6059

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  • The influence of snow cover conditions on the hydrological cycle in a mountain watershed

    Sugiyama, Whitaker, Hayakawa

    Trans. JSIDRE238   115 - 122   2005年

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  • Estimating long-term variability of precipitation characteristics on the coastal region of Niigata Prefecture

    Zhang, Masuda, Sugiyama, Whitaker

    Trans. JSIDRE234   97 - 106   2004年

  • Stochastic flow duration curves for evaluation of flow regimes in rivers

    H Sugiyama, Vudhivanich, V, AC Whitaker, K Lorsirirat

    JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION39 ( 1 ) 47 - 58   2003年2月

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    記述言語:英語   出版者・発行元:AMER WATER RESOURCES ASSOC  

    A stochastic estimation of low flow in the upper reaches of streams is needed for the planning, development, and management of water resources and/or water use systems. In this paper, the definition and development procedure for the stochastic flow duration curve is presented and applied to five catchments located in eastern Japan and to two catchments in western Thailand. The probability distribution of N-year daily discharge data is extracted at various percentages of time for which specified discharges are equaled or exceeded in a water year. Such a distribution is usually represented with a straight line on log-normal probability paper. However, some of the probability plots for the annual minimum daily discharge are best represented with a straight line on Weibull probability paper. The effectiveness of the stochastic flow duration curve defined for the evaluation of flow regime is illustrated through its application. The ten year probability for the discharge exceeded 97 percent of the time may be recognized as an index of low flow. The recession shape of the lower part of the flow duration curve is dependent on the strength of low flow persistence.

    DOI: 10.1111/j.1752-1688.2003.tb01560.x

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  • Application of the distributed hydrology soil vegetation model to redfish creek, British columbia: model evaluation using internal catchment data

    A Whitaker, Y Alila, J Beckers, D Toews

    HYDROLOGICAL PROCESSES17 ( 2 ) 199 - 224   2003年2月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    The Distributed Hydrology Soil Vegetation Model is applied to the Redfish Creek catchment to investigate the suitability of this model for simulation of forested mountainous watersheds in interior British Columbia and other high-latitude and high-altitude areas. On-site meteorological data and GIS information on terrain parameters, forest cover, and soil cover are used to specify model input. A stepwise approach is taken in calibrating the model, in which snow accumulation and melt parameters for clear-cut and forested areas were optimized independent of runoff production parameters. The calibrated model performs well in reproducing year-to-year variability in the Outflow hydrograph, including peak flows. In the subsequent model performance evaluation for simulation of catchment processes, emphasis is put on elevation and temporal differences in snow accumulation and melt, spatial patterns of snowline retreat, water table depth, and internal runoff generation, using internal catchment data as much as possible. Although the overall model performance based on these criteria is found to be good, some issues regarding the Simulation of internal catchment processes remain. These issues are related to the distribution of meteorological variables over the catchment and a lack of information on spatial variability in soil properties and soil saturation patterns. Present data limitations for testing internal model accuracy serve to guide future data collection at Redfish Creek. This study also illustrates the L challenges that need to be overcome before distributed physically based hydrologic models can be used for simulating catchments with fewer data resources. Copyright (C) 2003 John Wiley Sons, Ltd.

    DOI: 10.1002/hyp.1119

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  • Hydrological characteristics during cold season in a snowy mountain basin.

    Sugiyama, Whitaker, Yawata, Hirose

    Trans. JSIDRE228   57 - 64   2003年

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  • Impact of climate on flow regimes of the upper reaches of streams

    H Sugiyama, Vudhivanich, V, AC Whitaker, K Lorsirirat

    WATER RESOURCES SYSTEMS-HYDROLOGICAL RISK, MANAGEMENT AND DEVELOPMENT281 ( 281 ) 141 - 147   2003年

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    記述言語:英語   出版者・発行元:INT ASSOC HYDROLOGICAL SCIENCES  

    Comparison of flow regimes in the upper reaches of streams in the temperate zone (eastern Japan) and the tropical monsoon zone (western Thailand), and evaluation of an index of low flow are carried out aiming towards the synthesis of water resources evaluation. The flow regimes of the upper reaches of streams are stochastically evaluated by applying the stochastic flow duration (SFD) curve. On the basis of a comparison of values read from the SFD curve with the 10-year probability value, it is shown that the discharge exceeded 97% of time in the tropical monsoon zone is only about one-fifteenth that of the temperate zone. This difference indicates that this flow regime is uncomfortable for planning if a water resources planner evaluates a flow with the 10-year probability in the tropical zone. It may be argued that a more severe probability of occurrence (i.e. longer than 10 years) should be adopted for the design of water resources facilities in the tropical monsoon zone. By comparing the recession shape of the lower part of the flow duration curve, it is seen that the persistency of low flow in the temperate zone is stronger than that in the tropical monsoon zone. The index of low flow is also discussed by examining the relation between the index used in Japan and that in the United States of America. The relationship between the 10-year probability for annual minimum flow averaged over a consecutive period of seven days (Q(10.7)) of a given year and the 10-year probability value for the discharge exceeded 97% of the time (Q97(10)) is strong. This implies that the Q97(10) index used in Japan can be recognized as an index of low flow.

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  • Evaluating peak flow sensitivity to clear-cutting in different elevation bands of a snowmelt-dominated mountainous catchment

    A Whitaker, Y Alila, J Beckers, D Toews

    WATER RESOURCES RESEARCH38 ( 9 ) 1172   2002年9月

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    記述言語:英語   出版者・発行元:AMER GEOPHYSICAL UNION  

    [1] A hydrologic model of the mountainous snowmelt-dominated Redfish Creek catchment (British Columbia) is used to evaluate Interior Watershed Assessment Procedure (IWAP) guidelines regarding peak flow sensitivity to logging in different elevation bands of a basin. Simulation results suggest that peak flow increases are caused by greater snow accumulation and melt in clear-cut areas while similar evapotranspiration rates are predicted under forested and clear-cut conditions during spring high flow. Snow accumulation and melt are clearly related to elevation, but the relationship between logging elevation and peak flow change is more complex than perceived in the IWAP. Logging in the bottom 20% of the catchment causes little or no change in peak flow because of the small low-elevation snowpack and the timing of snowmelt, while clear-cut area alone appears to be a good indicator of peak flow increases due to logging at higher elevation. Temporal variability in peak flow changes due to clear-cutting is substantial and may depend more on temperatures during snowmelt than on the size of the snowpack. Long-term simulations are needed to improve quantitative estimates of peak flow change while the importance of watershed topographic characteristics for snowmelt and peak flow generation must be further examined.

    DOI: 10.1029/2001WR000514

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  • Evaluating peek flow snsitivity to clear-cutting in different elevation bouds of a snowmelt-dominated mountainons cetchment

    Wate Resoures Research38(9), 1172   2002年

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  • Evaluation of flow regimes in the upper reaches of streams using the stochastic flow duration curve

    Sugiyama, Whitaker

    Proceedings of Symposium on Water Resources, Tokyo, August 2002   627 - 632   2002年

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  • Modelling of peak flow change using the DHSVM model.

    Whitaker, Alila, Toews

    Watershed Assessment in the Southern Interior of British Columbia.British Columbia Ministry of Forests, Working Paper 57/2001   94 - 111   2001年

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  • Consideration on the stochastic flow duration curve applied to the evaluation of flow fluctuation in upper reaches of streams.

    Sugiyama, Botou, Whitaker, Hirai

    Trans. JSIDRE213   33 - 42   2001年

  • Evaluation of existing hydrological models for use in assessing the impact of forest management on peak flows.

    Whitaker, Alila, Calvert, Toews

    Canadian Water Resources Association 5lst Ann. Conference Procedings, Mountains to sea: Human Interaction with the Hydrologic Cycle, Victoria, BC.   67 - 71   1998年

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  • Assessing stream channel stability thresholds using flow competence estimates at bankfull stage.

    Olsen, Whitaker, Potts

    J. of American Water Resources Association33 ( 6 ) 1197 - 1207   1997年

  • Validation of two threshold models for bed load initiation in an upland gravel bed stream.

    Whitaker, Potts

    Proceedings of the Annual Symposium of the American Water Resources Association, Watershed Restoration Management, Syracuse, New York   85 - 94   1996年

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▶ 全件表示

共同研究・競争的資金等の研究

  • Forest influences on snow accummulation and snowmelt in temperate forests

    2002年

    Grant-in-Aid for Scientific Research 

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    資金種別:競争的資金

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  • Suspended and bedload transport processes in gravel-bed rivers

    2000年

    Grant-in-Aid for Scientific Research 

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    資金種別:競争的資金

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  • Runoff generation in headwater regions

    2000年

    Grant-in-Aid for Scientific Research 

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    資金種別:競争的資金

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