Urban moisture and dry islands: spatiotemporal variation patterns and mechanisms of urban air humidity changes across the globe

作者：Xinjie Huang, Jiyun Song · 发表于：Environmental Research Letters · 年份：2023 · DOI：10.1088/1748-9326/acf7d7 · 被引用次数：51 · 研究领域：Urban Heat Island Mitigation、Urban Green Space and Health、Building Energy and Comfort Optimization

Abstract Urbanization-induced atmospheric moisture changes, embodied as urban moisture island (UMI) and urban dry island (UDI) effects, are not as thoroughly understood as the urban heat island (UHI) effects, despite their significant influence on human comfort and well-being. This paper offers the first systematic review and quantitative meta-analysis of global urban–rural humidity contrasts, aiming to advance our comprehension of the mechanisms, intensity, patterns, and implications of urban humidity changes. The meta-analysis compiles observational data from 34 studies across 33 cities. It reveals that mid-latitude cities predominantly exhibit moderate UMI and UDI effects, and cities with low mean annual precipitation and distinct dry/wet seasons, however, exhibit extreme UMI and UDI effects. The diurnal cycle analysis presents more pronounced UMI effects at night, largely due to increased evapotranspiration and delayed dewfall linked with UHI. On a seasonal scale, UDI effects dominate in spring, while UMI effects peak in winter for mid-latitude cities and in summer for low-latitude cities. In addition, city characteristics such as topography, morphology, and size significantly shape urban–rural humidity contrasts. Coastal cities are subject to sea-breeze circulation, importing moisture from sea to land, whereas mountainous cities can accumulate humidity and precipitation due to geographical barriers and vertical airflow. High-density urban areas generally experience heigh...