Local and regional urban surface heterogeneity produces diverse urban climates, significantly impacting water use, energy consumption, and human health. This study examines urban energy flux variability across landcover and climate gradients for 2123 km² of urbanized Los Angeles County, USA, by using high resolution remote sensing combined with spatially distributed simulations with an urban energy balance model, covering the complete diurnal cycle of the remote sensing flights. Localized parameters, including landcover, plant type, albedo, building and tree height, and irrigation, were derived from hyperspectral and LiDAR imagery, and GIS. Modeled latent heat fluxes (LE) were linearly correlated with measured land surface temperature at the neighborhood scale (R² = 0.51), and modeled Bowen ratio values closely agreed with previous values derived from eddy covariance observations. LE across the region displayed spatial and temporal responses to irrigation and regional climate. Peak LE occurred 3 h before solar noon, driven by early morning irrigation characteristic of the region. This suggests that schedule-based water conservation policies could reduce the cooling capacity of urban vegetation in late afternoon. Additionally, a negative effect of distance from the coast on LE was observed to strengthen through the day, reducing LE in interior areas relative to coastal areas.

地方和区域城市表面的异质性产生了多种多样的城市气候，极大地影响了用水，能源消耗和人类健康。这项研究通过使用高分辨率遥感技术与空间分布模拟与城市能源平衡模型相结合，研究了美国洛杉矶县2123 km ²的城市土地覆盖和气候梯度之间的城市通量通量变异性，涵盖了偏远地区的完整日周期感应飞行。局部参数，包括土地覆盖物，植物类型，反照率，建筑物和树木的高度以及灌溉，均来自高光谱和LiDAR图像以及GIS。建模的潜热通量（LE）与在附近尺度（R ² = 0.51），并且模型化的Bowen比值与先前从涡度协方差观测中得出的值非常吻合。整个区域的LE表现出对灌溉和区域气候的时空响应。LE峰值出现在太阳正午前3小时，这是由于该地区的清晨灌溉特征所致。这表明基于时间表的节水政策可能会降低下午晚些时候城市植被的制冷能力。此外，观察到距离海岸的距离对LE的负面影响在一天当中不断加剧，相对于沿海地区，内部区域的LE减少了。