用深度网络同时捕捉全球植被生产力的共性规律与局部差异,提升预测精度和可解释性。
An Interpretable Implicit-Based Approach for Modeling Local Spatial Effects: A Case Study of Global Gross Primary Productivity
- 构建双分支神经网络,隐式编码时空异质性并提取全局共性特征
- 在2001-2020年全球数据上预测GPP,RMSE达0.836,优于LightGBM和TabNet
- 可视化揭示不同地区主导因子随时间空间演变,适合地球科学与气候建模研究者
在地球科学中,未观测因素呈现非平稳的空间分布,导致特征与目标间关系具有空间异质性。传统统计学习方法难以捕捉此类异质性,影响预测准确性和可解释性。尽管地理加权回归(GWR)能反映局部变化,却无法揭示全局模式或追踪空间异质性的连续演化。为此,我们提出一种新视角:利用深度神经网络同时建模不同位置间的共性特征与空间差异。所提方法为带有编码器-解码器结构的双分支网络。编码阶段,通过图卷积网络(GCN)与长短期记忆网络(LSTM)在时空条件图中聚合节点信息,将位置特异性时空异质性编码为隐式条件向量;同时,使用自注意力编码器提取数据中的位置无关共性特征。解码阶段,采用条件生成策略,在时空条件下基于数据特征预测响应变量及解释权重。模型基于2001至2020年全球气候与土地覆盖数据,对植被总初级生产力(GPP)进行预测。训练集包含5000万样本,测试集280万样本,模型取得RMSE 0.836,优于LightGBM(1.063)与TabNet(0.944)。可视化分析表明,该方法可揭示不同时间和空间下主导因子的分布差异。
原文摘要 · Abstract (English)
In Earth sciences, unobserved factors exhibit non-stationary spatial distributions, causing the relationships between features and targets to display spatial heterogeneity. In geographic machine learning tasks, conventional statistical learning methods often struggle to capture spatial heterogeneity, leading to unsatisfactory prediction accuracy and unreliable interpretability. While approaches like Geographically Weighted Regression (GWR) capture local variations, they fall short of uncovering global patterns and tracking the continuous evolution of spatial heterogeneity. Motivated by this limitation, we propose a novel perspective - that is, simultaneously modeling common features across different locations alongside spatial differences using deep neural networks. The proposed method is a dual-branch neural network with an encoder-decoder structure. In the encoding stage, the method aggregates node information in a spatiotemporal conditional graph using GCN and LSTM, encoding location-specific spatiotemporal heterogeneity as an implicit conditional vector. Additionally, a self-attention-based encoder is used to extract location-invariant common features from the data. In the decoding stage, the approach employs a conditional generation strategy that predicts response variables and interpretative weights based on data features under spatiotemporal conditions. The approach is validated by predicting vegetation gross primary productivity (GPP) using global climate and land cover data from 2001 to 2020. Trained on 50 million samples and tested on 2.8 million, the proposed model achieves an RMSE of 0.836, outperforming LightGBM (1.063) and TabNet (0.944). Visualization analyses indicate that our method can reveal the distribution differences of the dominant factors of GPP across various times and locations.
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