基于注意力机制与加权趋势损失的风速订正方法

Attention Mechanism and Weighted Trend Loss for Wind Speed Correction

  • 摘要: 该文旨在改进风速订正模型,以提高第6代跨学科气候研究模式(Model for Interdisciplinary Research on Climate Version 6,MIROC6)历史时期10 m风速的模拟准确性。研究基于Informer模型,结合多层感知机,构造了非平稳Informer(Ns-Informer)10 m风速订正模型。研究提出了一种新的加权趋势均方误差损失函数,以优化模型在高风速条件下的订正性能,选取北京站、拐子湖站、茫崖站、吉安站4个代表站进行验证。结果表明:Ns-Informer在月尺度和年代际尺度上均能还原风速时间分布特征,订正后10 m风速的均方根误差降低20%~50%,在风速超过5 m·s-1时表现最佳。Ns-Informer订正后的月平均10 m风速演变趋势与观测吻合度提高。在夏季和秋季订正效果显著,月平均10 m风速均方根误差降低25%以上。年代际变化趋势的订正表明Ns-Informer能矫正MIROC6对风速长期变化趋势的偏差,订正后的风速序列捕获了不同站点风速长期的上升或下降趋势。未来情景检验进一步表明:Ns-Informer能在SSP1-2.6情景下对高风速阈值的订正稳定性优于MIROC6。Ns-Informer可以有效降低MIROC6的系统偏差,为未来气候变化情景下风速的精确预估提供参考。

     

    Abstract: To address the systematic bias in simulating 10-m wind speed using MIROC6 model within CMIP6 framework, a novel approach based on deep learning is proposed. A non-stationary Informer model (Ns-Informer) is integrated with an adaptive-length attention mechanism and a multilayer perceptron (MLP) dynamic adjustment module to enhance the model’s correction performance, particularly in high wind speed conditions. A new weighted trend-based mean squared error loss function is developed to optimize the correction process. This function integrates weighted error allocation with trend consistency constraints, effectively balancing the trade-off between minimizing errors at high wind speeds and preserving the temporal trends of wind speed distributions. The model utilizes a sparse attention mechanism that reduces computational complexity by concentrating on the most relevant interactions within the input data. Additionally, de-stationary factors (τ and Δ) are introduced to dynamically adjust attention weights, thereby enhancing the model’s ability to capture non-stationary features, particularly high-speed anomalies. The experimental dataset includes historical simulations from 1961 to 2014, SSP1-2.6 scenario projections for years from 2015 to 2022, and CN05.1 gridded observations. Four representative stations including Beijing (moderate wind speed), Guaizihu and Mangya (high wind speed), and Ji’an (low wind speed) are selected for validation. Results indicate that Ns-Stationary Informer model significantly enhances the spatiotemporal characteristics of wind speed at both seasonal and decadal scales. The root mean square error (RMSE) of ensemble mean is reduced by 20%-50% compared to raw MIROC6 outputs. Specifically, for high wind speed stations (Guaizihu and Mangya), the RMSE is reduced by as much as 60% when wind speeds exceed 5 m·s-1. Monthly-scale wind speed trends corrected by Ns-Informer are improved in their agreement with observations. Additionally, the correction is particularly effective during summer and autumn, with the monthly-scale root mean square error being reduced by an average of over 25%. Further validation for 2015-2022 period under SSP1-2.6 scenario confirms the model’s robustness, particularly in stabilizing corrections for high wind speed thresholds (greater than 5 m·s-1). This approach, by integrating non-stationary architecture optimization with dynamic loss function design, offers a new framework for correcting biases in climate models and enhances the accuracy of wind energy assessments in future climate change scenarios. Despite its advantages, this method is limited by its reliance on a single climate model (MIROC6) and a limited number of training ensemble members. Future work will expand this method to incorporate multi-model ensembles and long-term climate projections. The focus will be on further refining adaptive loss function and enhancing the model’s generalization capabilities across various regions and scenarios.

     

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