Abstract Land cover characteristics can produce changes in spatial and temporal variability in potential temperature (θ) at scales that are relevant to city inhabitants. Using data from 60 sensors positioned in five urban parks and surrounding residential neighborhoods in the semi-arid Salt Lake Valley, we evaluated the effect of turfgrass cover versus tree shading on spatial and temporal variation in microclimate in a semi-arid urban area. Our results indicated that the replacement of vegetation by impervious surfaces plays a role in microclimatic homogenization. Tree shading was associated with higher spatial variability of θ during the day, while turfgrass cover was associated with higher spatial variability of θ at night. Contrary to our expectation of tree shading governing daytime θ, we also found turfgrass cover to have an efficient cooling effect. This suggests a prominent role of turfgrass evapotranspiration enhanced by high atmospheric evaporative demand, high soil moisture availability, and increased radiation loads that are characteristic of semi-arid urban landscapes. Given that turfgrass cover was also associated with reduced θ at night, mixed tree and grass landscapes may be effective in alleviating the urban heat island effect in semi-arid urban settings.

中文翻译：

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植被对盐湖谷城市化小气候时空变化的影响

摘要 土地覆盖特征可以在与城市居民相关的尺度上产生潜在温度 (θ) 的空间和时间变化。我们使用位于半干旱盐湖谷五个城市公园和周边居民区的 60 个传感器的数据，评估了草坪覆盖与树木遮荫对半干旱城市地区小气候时空变化的影响。我们的结果表明，不透水表面替代植被在小气候均质化中起作用。树木遮荫与白天较高的 θ 空间变异性相关，而草坪覆盖与夜间较高的 θ 空间变异性相关。与我们对控制白天 θ 的树木阴影的期望相反，我们还发现草坪覆盖物具有有效的冷却效果。这表明高大气蒸发需求、高土壤水分可用性和增加的辐射负荷增强了草坪草蒸散的突出作用，这些都是半干旱城市景观的特征。鉴于草坪覆盖也与夜间 θ 的减少有关，混合树木和草地景观可能有效缓解半干旱城市环境中的城市热岛效应。