An overly complex urban climate/energy model would not be of much practical use in a decision support setting where a large number of year-long simulations are often necessary. While detailed modeling of urban momentum/energy exchanges can be attempted via Computational Fluid Dynamics (CFD) or mesoscale modeling, conducting multiple full year simulations in a design optimization or sensitivity analysis context is practically impossible. Furthermore, CFD models often do not consider climate/building energy exchanges. To address these limitations, standalone Urban Canopy Models (UCMs) have been developed, attempting to replace the full-fledged atmospheric representation with a computationally light equivalent. In this study, we investigate the impact of several modifications to a standalone Single-Layer Urban Canopy Model (SLUCM) for an arid region based on the prior availability of site-specific information. The suggested improvements are portable to SLUCM schemes incorporated within mesoscale models. The SLUCM will undergo several improvements and each variant will be evaluated based on its ability to predict UHI intensity and air-conditioning energy demand. Three original SLUCM improvements are covered in the present study. (1) We use actual radiation parameters instead of those generated for idealized geometries. It is shown that, in the absence of this improvement, standard UCMs can underestimate the average urban heat island intensity by 5% if using the Town Energy Balance (TEB) radiation scheme or overestimate it by 7% if using the Square Prism Urban Canopy (SPUC) radiation scheme. (2) We use the results of a prior steady-state RANS (Reynolds-Averaged Numerical Simulation) simulation to replace some of the default morphological parameters of the UCM by the more accurate values derived from the RANS results. It is shown that, in the absence of this improvement, standard UCMs using default empirical relations can overestimate the average urban heat island intensity by up to 22%. (3) Instead of using the empirically calculated default value of the urban canyon wind speed, we estimate it directly from the concomitant rural value using a regression model trained by historical measurements. It is shown that, in the absence of this improvement, standard UCMs can underestimate the average canyon wind velocity by more than 12%, although the other indicators (UHI, cooling demand) are not significantly affected.

在决策支持环境中，过于复杂的城市气候/能源模型并没有太多实际用途，因为在决策支持环境中，经常需要进行大量长达一年的模拟。尽管可以通过计算流体动力学（CFD）或中尺度模型尝试对城市动量/能量交换进行详细建模，但实际上不可能在设计优化或敏感性分析的情况下进行多个全年模拟。此外，CFD模型通常不考虑气候/建筑能量交换。为了解决这些限制，已经开发了独立的城市机盖模型（UCM），试图用计算上的光当量代替完整的大气表示。在这个研究中，我们将根据特定地点信息的先前可用性，对干旱地区的独立单层城市雨棚模型（SLUCM）进行几次修改的影响进行调查。建议的改进可移植到中尺度模型中并入的SLUCM方案。SLUCM将进行几项改进，并且将根据其预测超高强度和空调能源需求的能力来评估每个变体。本研究涵盖了SLUCM的三个原始改进。（1）本研究涵盖了SLUCM的三个原始改进。（1）本研究涵盖了SLUCM的三个原始改进。（1）我们使用实际的辐射参数，而不是为理想化的几何图形生成的辐射参数。结果表明，在没有这种改进的情况下，如果使用城镇能源平衡（TEB）辐射方案，标准的UCM可以将平均城市热岛强度低估5％，如果使用方棱镜城市雨棚，则可以将其平均高估7％（ SPUC）辐射方案。（2）我们使用先前的稳态RANS（雷诺平均数值模拟）仿真结果将UCM的一些默认形态参数替换为从RANS结果得出的更准确的值。结果表明，在没有这种改进的情况下，使用默认经验关系的标准UCM可以高估平均城市热岛强度达22％。（3）我们不使用经验计算出的城市峡谷风速默认值，而是使用历史测量值训练的回归模型直接从伴随的农村值中估算出默认值。结果表明，在没有这种改进的情况下，尽管其他指标（UHI，冷却需求）并未受到明显影响，但标准的UCM可能低估了平均峡谷风速12％以上。