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A Multilevel Surrogate Model-Based Precipitation Parameter Tuning Method for CAM5 Using Remote Sensing Data for Validation

delete2025-01-25
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OA
AI
X
Xianwei Wu
胡亮 (Liang Hu)
W
Wang, Lanning
L
Lu, Haitian
F
Fu, Haohuan
DOI:10.3390/rs17030408delete
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Abstract

Abstract

En 中文
The uncertainty of physical parameters is a major factor contributing to poor precipitation simulation performance in Earth system models (ESMs), particularly in tropical and Pacific regions. To address the high computational cost of repetitive ESM runs, this study proposes a multilevel surrogate model-based parameter optimization framework and applies it to improve the precipitation performance of CAM5. A top-level surrogate model using gradient boosting regression trees (GBRTs) was constructed, leveraging the candidate point (CAND) approach applied to balance exploration and exploitation. A bottom-level surrogate model was then built based on a small, selected dataset; we designed a trust region approach to adjust the sampling region during the bottom-level tuning process. Experimental results demonstrate that the proposed method achieves fast convergence and significantly enhances precipitation simulation accuracy, with an average improvement of 19% in selected regions. In integrating optimization results through a nonuniform parameterization scheme and parameter smoothing, substantial improvements were observed in the South Pacific, Ni & ntilde;o, South America, and East Asia. Comparisons with remote sensing data confirm that the optimized precipitation simulations do not introduce significant biases to other variables, validating the effectiveness and robustness of the proposed method.
Keywords:
surrogate model
parameter tuning
CAM5 precipitation
nonuniform parameter parameterization scheme

Journal

Remote Sensing cover
Remote Sensing
IF:
4.1
Papers:
7.1K
Citations:
15.1W

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