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水文モデルの効率化手法の提案(Streamlining Hydrological Models with Improved Parameter Learning Techniques)

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2025-07-03 パシフィック・ノースウェスト国立研究所(PNNL)

米国パシフィックノースウェスト国立研究所(PNNL)による研究は、情報理論を活用して水文モデルのパラメータ学習を効率化する手法を提案しました。複雑化する統合水文モデル(ATS)のパラメータ調整には多くの流量観測データが必要ですが、本手法では相互情報量(MI)に基づき、パラメータ推定に最も寄与する観測期間と地点を選別。デラウェア州ネヴァーシンク川流域の11観測所を対象に分析した結果、モデルの出口流量予測は少なくとも4年分の観測が必要であることが判明し、MIによる観測選定がキャリブレーション性能と高い相関を示しました。さらに、有益な地点のデータだけでも近隣地点の流量予測が可能であり、キャリブレーション対象地域を縮小できることが示唆されました。このアプローチにより、観測データと計算コストの最適化が実現し、他の流量観測や生物地球化学プロセスにも応用可能です。

<関連情報>

統合水文モデルにおけるパラメータ学習とキャリブレーションの最適化: 観測の長さと情報の影響 Optimizing parameter learning and calibration in an integrated hydrological model: Impact of observation length and information

Peishi Jiang, Pin Shuai, Alexander Y. Sun, Xingyuan Chen

Journal of Hydrology  Available online: 31 August 2024

DOI:https://doi.org/10.1016/j.jhydrol.2024.131889

水文モデルの効率化手法の提案(Streamlining Hydrological Models with Improved Parameter Learning Techniques)

Highlights

  • We studied the impact of the observation length and information on integrated hydrological model calibration.
  • Information-theoretic metrics unveil to what extent observed streamflow can be used in learning model parameters.
  • Informative observations can be used to constrain the model to predict the streamflows at a nearby gage.

Abstract

Integrated hydrological modeling is gaining popularity due to its mechanistic representation of the surface and subsurface processes. However, estimating the parameters of such process-based models can be computationally expensive if careful consideration is not given to the length of streamflow observations used during model calibration. Here we evaluate the influence of the calibration period, the role of streamflow information content, and the gage location in parameter learning and calibration of a fully integrated hydrological model, the Advanced Terrestrial Simulator (ATS). We conducted the study at the Upper Neversink River Watershed within the Delaware River Basin, where streamflow observations are available at 11 gages with varying record lengths. We leveraged a recently proposed knowledge-informed deep learning technique for parameter estimation. To assess the impact of observation period and gage location, model parameters were learned on scenarios using different chunks of streamflow observations, including (1) using only one year or consecutive multiple years of streamflow observations at the watershed outlet and (2) using one shared year of observations at each of the sub-catchment gages, with the period from 1991-10-01 through 1999-09-30 as the overall calibration period. Using the estimated parameters, ATS was rerun for each scenario and evaluated on a subsequent period from 1999-10-01 through 2002-09-30. Results show that the basin outlet discharge prediction is mostly improved when using at least four years of observations for parameter estimation. Further, the performance of the calibrated ATS run correlates with the information content of the observed streamflows, suggesting that the information-theoretic metrics could be indicators for selecting the observation period for parameter estimation. Finally, we find that observations from an informative gage can be used in learning parameters to predict the streamflow at a nearby gage, which would potentially lower the computational expense by reducing the watershed domain used in calibration. Our success underscores the potential of using information theory to achieve robust model parameter estimation on a reduced computational budget.

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