Mechanisms and Empirical Modeling of Evaporation from Hardened Surfaces in Urban Areas

Zhang

et al. 2022

Hydrological Processes

Self Cite

Urban artificial water dissipation is a concomitant process of human water use in built‐up areas that can absorb heat through evapotranspiration, reduce air temperature, transfer surface water to the atmosphere, and participate in the urban water cycle. In the context of increased urbanization, the impact of artificial water dissipation on urban climates cannot be ignored. In this study, calculation models for artificial water dissipation from different underlying surface types (buildings, hardened ground, soil, and vegetation) were introduced into an urban canopy model and coupled with the weather research and forecasting (WRF) model for mesoscale weather simulations of the Beijing area. Observational datasets of temperature and humidity from automatic weather stations in Beijing were used for validation. Results showed that the coupled model could reproduce the temperature and humidity of urban weather stations in Beijing more accurately compared to simulations that did not employ an urban canopy model or that adopted a traditional urban canopy model. In the Beijing urban area, the latent heat flux of NON, urban canopy model, and artificial water dissipation into the UCM are approximately 0, 35, and 65 W/m2, respectively, and the anthropogenic latent heat is about 30 W/m2. Incorporating urban artificial water dissipation into the urban canopy model reduced the urban air temperature by 0.2°C and increased the specific humidity by 0.6 g/kg, alleviating urban heat island effects and increasing humidity. These findings indicate that artificial urban water dissipation plays an important role in urban weather and climate that should be considered by urban canopy models. In the future, this model can be coupled into WRF for more accurate mesoscale weather simulations.

“…The amount of water applied to hardened ground can be expressed as:

E_{sh} goodbreak= \frac{H_{A} \times A_{normalr 1}}{A_{r}}

Section: Methodsmentioning

confidence: 99%

Incorporating an urban canopy model with artificial water dissipation into weather research and forecasting: A case study for Beijing

Luo

Zhang

et al. 2022

Hydrological Processes

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“…In Dongcheng District, it exceeded 80 thousand m 3 for every season, with more than 120 thousand m 3 in summer. Districts with lower figures are in suburbs with a less permanent population, including the Shijingshan, Mentougou, Yanqing, Huairou, Miyun, and Pinggu districts, with the evaporation amount generated in each season less than 120 thousand m 3 .…”

Section: Distribution Of Human Body Perspiration In Different Seasonsmentioning

confidence: 99%

“…According to the forecast of the United Nations Population Division, the urbanization rate of every developing country or region in the world will exceed 50% in 2030, and two-thirds of the population will live in cities by 2050 [ 2 ]. With the rapid urbanization process, human beings continue to congregate in urban areas, and urban transformation activities are becoming more frequent [ 3 , 4 ], altering the original water cycle system from a single cycle dominated by nature to a cycle dominated by both nature and human society, which is called a natural-social dualistic water cycle system [ 5 ]. As an essential part of the urban water cycle process, urban regional evapotranspiration [ 6 , 7 ] is an important source of urban water vapor, and it has a significant impact on urban microclimate changes and water cycle flux calculations [ 8 ], including outdoor natural water evaporation and indoor water dissipation from humans [ 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

The Considerable Water Evaporation Induced by Human Perspiration and Respiration in Megacities: Quantifying Method and Case Study in Beijing

et al. 2022

IJERPH

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The water cycle in urban areas is called the natural-social dualistic water cycle, and it is driven not only by natural forces, but also by human activities. As the drivers of the social water cycle, human perspire continuously, and this is often overlooked as a contributing factor to the water cycle. This paper proposes a method for quantifying the water evaporation induced by human perspiration and respiration in megacities. A calculation based on the sweating prediction model was applied to the city of Beijing to evaluate the evaporation from the human body. The results show that the greatest volume of evaporation produced by human occurs in summer, and the least in spring. The total evaporation produced by human was converted to the evaporation on unit area of the city and reached 5075.2 m3/km2 in the six core districts of Beijing. According to the calculation, the total volume was considerable and reached 14.0 million m3 in 2020, which was equivalent to the annual evapotranspiration from an area of 104.9 km2 of Acer truncatum forest (15 cm diameter at breast height, afforestation density 800 plants/hm2), and even twice the annual total water use in Tartu, Estonia. The results of the study provide a reference for dualistic water cycle research and water cycle flux calculation in urban areas.

“…Previous studies have mainly analyzed and calculated urban natural ET (Meng & Zhang, 2019; Ramamurthy & Bou‐Zeid, 2014; Van Stan et al, 2017; Zhou et al, 2021), the research objects are mostly impervious surfaces, soil, trees, etc. And several methods have been used to estimate urban ET, including the water and heat balance method, aerodynamics, and Penman–Monteith.…”

Section: Introductionmentioning

confidence: 99%

“…The BWE is mainly influenced by the number of building floors (Liu et al, 2018), the level of economic development (Bao & Chen, 2015; Duarte et al, 2014; Guo, Li, et al, 2021; Wang & Li, 2018; Yoo, 2007; Zhang et al, 2021), and the type of water use activity (Zhou et al, 2019). Water evaporation inside buildings is more stable than ET in urban open‐air environments (Zhou et al, 2019), and outdoor ET is more susceptible to rainfall or air temperature (Zhou et al, 2021). The daily water use activities of humans in buildings are relatively stable.…”

Section: Introductionmentioning

confidence: 99%

Using nighttime light data to estimate water evaporation inside buildings in China's urban areas

Gao

J American Water Resour Assoc

Mei

et al. 2023

Self Cite

The urban water cycle is one of the most significant research topics in hydrology and provides the foundation for urban water resource management (Wei et al., 2018). The process of urban water cycle can be generalized as "supply-consumption-dissipation-drainage-recyclingreuse". Urban water dissipation mainly includes the evapotranspiration (ET) occurs on impervious surfaces, water, soil, vegetation, etc., as well as the evaporation happens indoor due to various human water use activities in dualistic water cycle (Zhou et al., 2019). Cities are typical natural-social dualistic water cycle areas (Wang et al., 2013), it is more difficult to study urban ET because of the complexity and diversity of urban underlying surfaces. Buildings are major underlying surfaces in cities because their roofs exist as impervious surfaces, while indoor areas are vital places for evaporation in the social water cycle (Zhou et al., 2019). For urban citizens, the major water activity to satisfy their