山地流域の水・土砂流出における空間スケールの影響(3):数値解析モデル上の取り扱い事例  [in Japanese] Effects of Spatial Scales on Runoff / Sediment Transport in Mountain Catchments (3) -Review for the Treatments of Numerical Models  [in Japanese]

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Abstract

<p> 本稿は,山地流域の水・土砂流出現象の数値解析モデルにおける空間スケールの影響の取り扱い方に関する既往研究を調べた.まず,代表的な数値解析モデルを利用した研究における,(1)最小の空間スケールとその決定方法,(2)入力データとして利用する空間分布情報,(3)支配方程式の空間スケール依存性の3点を整理した.その結果,(1)の最小空間スケールは,利用する標高データの最小の空間スケールに依存すること,(2)の利用する空間分布情報は標高・土地利用・植生データが多く,その他は実測に基づくデータではないこと,(3)の支配方程式は対象とする斜面や河道などの「場」に依存し,空間スケールに応じて明示的に支配方程式が変化するモデルはなかった.次に,空間スケールの影響の取り扱い方自体を検討した既往研究を調べた.その結果,水流出モデルに関しては集中化できる面積(基準面積)や入力する空間分布情報の相対的重要性に関する知見が集積されつつあるが,土砂流出モデルについては同様の研究報告はなかった.以上を踏まえ,水・土砂流出モデリングにおける空間スケールの取り扱い方の今後の在り方の一つを提示する.</p>

<p> We reviewed the treatment of spatial scales in numerical models of runoff and sediment transport to elucidate current problems and to identify avenues for future research. We specifically examined the following questions: (1) Which spatial scale is used in existing modeling and how was it decided? (2) What spatial information was used? (3) Do the governing equations differ with spatial scale? Results show that the smallest spatial scale in distributed models was determined by the spatial resolution of spatially distributed information used in modeling, although lumped models were applicable at any scale. Some physical parameters used in modeling, aside from elevation, land use and vegetation cover, were not based on field-based information. Results demonstrate that the governing equations differ depending on locations within the watershed (i.e., hillslopes and channels) presenting different processes for runoff and sediment transport. Nevertheless, no report of the relevant literature describes a study with changed governing equations along with the changes in spatial scales. We also reviewed modeling studies of how we should treat the effects of spatial scale in runoff modeling, which revealed that they had reported minimum and the maximum spatial scales for lumping runoff mechanisms and the relative importance of spatial data used as input and parameters, although no attempts have been reported for a change in governing equations with spatial scale. We were unable to find similar studies of sediment runoff modeling. In summary, we suggest improvement of these findings and their use for modeling rainfall runoff and sediment transport mechanisms for better hydrological science.</p>

Journal

  • JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES 31(4), 245-261, 2018

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

Codes

  • NII Article ID (NAID)
    130007481580
  • NII NACSIS-CAT ID (NCID)
    AN10088049
  • Text Lang
    JPN
  • ISSN
    0915-1389
  • NDL Article ID
    029155013
  • NDL Call No.
    Z15-619
  • Data Source
    NDL  J-STAGE 
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