<p>Satellite precipitation products (SPPs) are crucial for applications such as water resource management and flood forecasting. A key challenge remains the accurate evaluation and subsequent correction of SPP biases. This study develops a machine-learning-driven hierarchical framework for both evaluating and correcting SPPs, demonstrated through a case study in Guangxi, China. First, we account for the uncertainty in rain gauge observations by formulating them as interval-valued data. A novel distance-based evaluation index is proposed, and a corresponding bias correction rule is established based on the resulting performance hierarchy. The precipitation observation is modeled as a function of the satellite precipitation at a target grid point, its <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\mathbf{K}\)</EquationSource> </InlineEquation>-nearest neighbors, and the geographic attributes of the ground station. This functional relationship is captured by a specially designed neural network. Second, using daytime IMERG data over Guangxi, we illustrate the proposed evaluation index and correction model. By implementing a hierarchical training strategy for the neural network, the bias in SPPs is significantly reduced, particularly for heavy precipitation events exceeding 50&#xa0;mm. Finally, comparative results and discussions are presented, highlighting the advantages of the proposed model over existing approaches.</p>

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Evaluating and enhancing the performance of satellite precipitation products by considering uncertainty in rain gauge observations

  • Tai Wei,
  • Xian-Ci Zhong,
  • Yang Gao

摘要

Satellite precipitation products (SPPs) are crucial for applications such as water resource management and flood forecasting. A key challenge remains the accurate evaluation and subsequent correction of SPP biases. This study develops a machine-learning-driven hierarchical framework for both evaluating and correcting SPPs, demonstrated through a case study in Guangxi, China. First, we account for the uncertainty in rain gauge observations by formulating them as interval-valued data. A novel distance-based evaluation index is proposed, and a corresponding bias correction rule is established based on the resulting performance hierarchy. The precipitation observation is modeled as a function of the satellite precipitation at a target grid point, its \(\mathbf{K}\) -nearest neighbors, and the geographic attributes of the ground station. This functional relationship is captured by a specially designed neural network. Second, using daytime IMERG data over Guangxi, we illustrate the proposed evaluation index and correction model. By implementing a hierarchical training strategy for the neural network, the bias in SPPs is significantly reduced, particularly for heavy precipitation events exceeding 50 mm. Finally, comparative results and discussions are presented, highlighting the advantages of the proposed model over existing approaches.