Dissipation of water in urban area, mechanism and modelling with the consideration of anthropogenic impacts: A case study in Xiamen

Mei

et al. 2021

Preprint

Self Cite

Urban water dissipation is increasing gradually as urbanization progresses. Urban water dissipation mainly includes the dissipation of water in buildings and natural water evapotranspiration. Previous studies have mainly focused on calculating natural evapotranspiration in urban areas and have overlooked the dissipation of water in buildings under the influence of strong human-related water use activities. In this paper, the concept of building water dissipation (BWD) was proposed to describe the phenomenon that water dissipation occurs inside buildings. Moreover, a BWD calculation model was established and applied to calculate global building water dissipation. To reveal the specific water dissipation inside buildings, it is necessary to obtain the urban building floor area first. This paper proposed a new method to calculate the urban building floor area based on global nighttime light data obtained from NPP-VIIRS. Taking the floor area results into the BWD calculation model, the global building water dissipation in urban areas was found to be 127 billion m3 in 2015. The vast building water dissipation that occurs in urban areas mostly results from rapidly developing economies and intense human activities. The results provide a basic understanding of the nexus between water resources and the energy-heat island effect in urban areas.

Section: Building Water Dissipationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Calculating the water dissipation of buildings in urban areas based on global nighttime light data

Han

Mei

et al. 2021

Preprint

Self Cite

“…However, the research on evaporation of hardened surfaces is relatively weak, which may be due to two aspects: the monitoring of surface evaporation is difficult and the heterogeneity of hardened surfaces is high [ 16 , 17 ]. Hardened surfaces can be divided into impervious surfaces and pervious surfaces [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

“…The water-storage capacity and the maximal wet surface fraction constitute the evaporation area of impervious surfaces [ 19 ]. For municipal roads in urban areas, water on roads comes from natural rainfall and artificial sprinkling [ 17 ]. Furthermore, the evaporation on the imperious surfaces occurs after rain or after artificial sprinkling [ 16 , 20 , 21 , 22 ] and plays a crucial role in road surface temperature simulations on rainy days [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

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

Zhou

Chu

et al. 2021

IJERPH

Self Cite

Urban evaporation, as an essential part of local water vapor resources in urban areas, has often been underestimated. One possible reason is that the evaporation of urban hardened surfaces is seldom considered and poorly understood in urban evaporation estimation. This study focused on the mechanisms and calculation of evaporation on hardened surfaces in urban areas. Experimental monitoring was used to monitor the processes and characteristics of evaporation on hardened surfaces. Mathematical models based on water quantity constraints were built to calculate evaporation of hardened surfaces. The results showed that: The interception abilities for rainwater and rainfall days of impervious hardened surfaces determine their evaporated water amount, which means no water, no evaporation for the impervious surfaces. The greater evaporation of artificial sprinkling on roads happened in fewer days of rainfall and frost. The evaporation of pervious hardened ground is continuous compared to the impervious surface. Its soil moisture in the sub-layer of permeable concrete decreases periodically with a period of one day. The evaporation of hardened surfaces occupies 16–29% of the total amount of evaporation in the built-up areas in cities. Therefore, the hardened surface evaporation has great significance on the urban hydrological cycle and urban water balance.

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

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.