The present study investigated the impacts of urban geometry on incident solar radiation on building envelopes. A three-dimensional model was developed and applied to examine these relationships, with implications for building landscapes as a potential heat source for urban heat islands. In the model, we classified building envelopes into three types, including ground, roofs, and building façades. Satisfactory model performance was confirmed by comparing measured and predicted incident solar radiation results. Furthermore, we developed the Incident Solar Radiation Prediction Index (ISRPI) to address relationships between urban geometry and incident solar radiation. Our overall results showed the solar irradiance incident on building envelopes was significantly affected by urban geometry. Building façades consistently shared a large amount of the building landscape’s total surface area and therefore determined more influence on variation in incident solar radiation. Weather conditions showed strong influence on incident solar radiation, primarily due to variation in atmospheric transmittance. Diffuse radiation demonstrated a larger share of incident solar radiation on the cloudy sampling day. ISRPI, which cumulatively combined the strengths of several traditional urban morphological metrics, exhibited a strong linear relationship with incident solar radiation under sunny and cloudy weather conditions. This index provided a more convenient approach to estimate the spatial-temporal variations of solar radiations at urban scale.

本研究调查了城市几何形状对建筑围护结构上入射太阳辐射的影响。开发了一个三维模型，并将其应用于检验这些关系，这对建筑景观作为城市热岛的潜在热源具有启示意义。在模型中，我们将建筑围护结构分为三种类型，包括地面，屋顶和建筑立面。通过比较测得的和预测的入射太阳辐射结果，可以确定令人满意的模型性能。此外，我们制定了入射太阳辐射预测指数（ISRPI），以解决城市几何形状与入射太阳辐射之间的关系。我们的整体结果表明，入射在建筑物围护结构上的太阳辐射受到城市几何形状的显着影响。建筑立面始终共享大量建筑景观的总表面积，因此确定了对入射太阳辐射变化的更多影响。天气状况对入射太阳辐射表现出强烈的影响，这主要是由于大气透射率的变化。在多云的采样日，散射辐射表明入射太阳辐射的份额更大。ISRPI累积地结合了几种传统城市形态学指标的优势，在晴天和阴天的天气条件下，与入射太阳辐射表现出很强的线性关系。该指数提供了一种更方便的方法来估算城市规模的太阳辐射的时空变化。