融合多源数据的城市局地气候区精细分类方法研究——以武汉市为例

Refined Mapping of Urban Local Climate Zones by Integrating Multi-source Data:A Case Study of Wuhan,China

  • 摘要: 在气候变化加剧和极端高温事件频发背景下,城市热环境评估、气候适应性规划和风险识别对精细化空间分类框架提出了更高要求。局地气候区(local climate zone,LCZ)分类作为连接城市空间形态与局地气候差异的基础框架,是气候变化背景下城市环境研究的重要支撑,但在复杂城市环境中仍存在类别混淆、分类精度不足等瓶颈问题。以湖北省武汉市为研究区,融合多源地理空间数据,提取建筑三维形态、地表覆盖、植被状态、光谱响应和功能约束等特征,构建知识规则—机器学习相结合的两阶段LCZ分类方法。基于独立人工解译样本的验证结果表明,120 m分辨率LCZ分类结果总体精度为0.899,Kappa系数为0.867;与相同验证样本下的全球LCZ产品相比,所构建方法结果的总体精度提高了0.130,Kappa系数提高了0.186。多尺度对比表明,120 m分类尺度在精度与空间细节表达之间具有相对均衡的表现。基于地表温度的外部一致性检验表明,分类结果能够有效反映不同城市形态与地表覆盖单元的热环境差异,表明该方法具有较好的城市局部气候特征区分性。所构建的集成方法可为复杂城市空间LCZ高精度分类、热环境精细化评估与气候适应性规划提供技术支撑。

     

    Abstract: Objectives: Under intensifying climate change and increasingly frequent extreme heat events, urban thermal environment assessment, climate adaptation planning, and risk identification require more refined spatial classification frameworks. Local climate zone (LCZ) classification links urban spatial morphology with local climatic differences and provides an important basis for urban environmental research. However, LCZ classification in complex urban environments still faces bottlenecks such as class confusion and insufficient accuracy. The objective was to develop a refined LCZ classification method suitable for complex urban spaces and evaluate its local applicability. Methods: With Wuhan as the study area, multi-source geospatial data for 2020 were integrated to construct features related to three-dimensional building morphology, surface cover, vegetation conditions, spectral responses, and functional constraints. A two-stage LCZ classification method was formed by combining knowledge-rule-based initial classification with random forest supplementary classification. Classification accuracy, multi-scale performance, comparison with the global LCZ product, and land-surface-temperature-based external consistency were evaluated. Results: The 120 m LCZ classification result achieved an overall accuracy (OA) of 0.899, with an overall accuracy of 0.827 for built-up LCZ classes. Compared with the global LCZ product evaluated using the same validation samples, the OA and Kappa coefficient of the proposed result were higher by 0.130 and 0.186, respectively. Multiscale comparison showed that the 120 m classification scale achieved a relatively balanced performance between accuracy and spatial detail representation. The land surface temperature consistency test showed that the classification result effectively reflected thermal differences among urban morphology and surface-cover units, supporting the climatic interpretability and applicability of the LCZ classification method. Conclusions: The results can provide technical support for high-accuracy LCZ classification, refined urban thermal environment assessment, and climate adaptation planning in complex urban spaces.

     

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