Urbanization influences hydrologic cycle significantly on local,regional even global scale.With urbanization the water resources demand for dense population sharpened,thus it is a great challenge to ensure water suppl...Urbanization influences hydrologic cycle significantly on local,regional even global scale.With urbanization the water resources demand for dense population sharpened,thus it is a great challenge to ensure water supply for some metropolises such as Beijing.Urban area is traditionally considered as the area with lower evapotranspiration(ET) on account of the impervious surface and the lower wind speed.For most remote sensing models,the ET,defined as latent heat in energy budget,is estimated as the difference between net radiation and sensible heat.The sensible heat is generally higher in urban area due to the high surface temperature caused by heat island,therefore the latent heat(i.e.the ET) in urban area is lower than that in other region.We estimated water consumption from 2003 to 2012 in Beijing based on water balance method and found that the annual mean ET in urban area was about 654 mm.However,using Surface Energy Balance System(SEBS) model,the annual mean ET in urban area was only 348 mm.We attributed this inconsistence to the impact of anthropogenic heat and quantified this impact on the basis of the night-light maps.Therefore,a new model SEBS-Urban,coupling SEBS model and anthropogenic heat was developed to estimate the ET in urban area.The ET in urban area of Beijing estimated by SEBS-Urban showed a good agreement with the ET from water balance method.The findings from this study highlighted that anthropogenic heat should be included in the surface energy budget for a highly urbanized area.展开更多
Indoor humidity directly impacts the health of indoor populations. In arid and semi-arid cities, the buildings indoor humidity is typically higher than outdoors, and the presence of water vapor results from water diss...Indoor humidity directly impacts the health of indoor populations. In arid and semi-arid cities, the buildings indoor humidity is typically higher than outdoors, and the presence of water vapor results from water dissipation inside the buildings. Few studies have explored indoor humidity features and vapor distribution or evaluated water dissipation inside buildings. This study examined temperature and relative humidity （RH） changes in typical residential and office buildings. The results indicate a relatively stable temperature with vary range of-4-1~C and a fluctuation RH trend which is similarly to that of water use. We proposed the concept of building water dissipation to describe the transformation of liquid water into gaseous water during water consumption and to develop a building water dissipation model that involves two main parameters： indoor population and total floor area. The simulated values were verified by measuring water consumption and water drainage, and the resulting simulation errors were lower for residential than for office buildings. The results indicate that bathroom vapor accounts for 70% of water dissipation in residential buildings. We conclude that indoor humidity was largely a result of water dissipation indoors, and building water dissipation should be considered in urban hydrological cycles.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos. 51479088,41630856 & 51279208)
文摘Urbanization influences hydrologic cycle significantly on local,regional even global scale.With urbanization the water resources demand for dense population sharpened,thus it is a great challenge to ensure water supply for some metropolises such as Beijing.Urban area is traditionally considered as the area with lower evapotranspiration(ET) on account of the impervious surface and the lower wind speed.For most remote sensing models,the ET,defined as latent heat in energy budget,is estimated as the difference between net radiation and sensible heat.The sensible heat is generally higher in urban area due to the high surface temperature caused by heat island,therefore the latent heat(i.e.the ET) in urban area is lower than that in other region.We estimated water consumption from 2003 to 2012 in Beijing based on water balance method and found that the annual mean ET in urban area was about 654 mm.However,using Surface Energy Balance System(SEBS) model,the annual mean ET in urban area was only 348 mm.We attributed this inconsistence to the impact of anthropogenic heat and quantified this impact on the basis of the night-light maps.Therefore,a new model SEBS-Urban,coupling SEBS model and anthropogenic heat was developed to estimate the ET in urban area.The ET in urban area of Beijing estimated by SEBS-Urban showed a good agreement with the ET from water balance method.The findings from this study highlighted that anthropogenic heat should be included in the surface energy budget for a highly urbanized area.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFC0401401)the National Natural Science Foundation of China(Grant Nos.51522907&51739011)the Research Fund of the State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research(Grant No.2017ZY02)
文摘Indoor humidity directly impacts the health of indoor populations. In arid and semi-arid cities, the buildings indoor humidity is typically higher than outdoors, and the presence of water vapor results from water dissipation inside the buildings. Few studies have explored indoor humidity features and vapor distribution or evaluated water dissipation inside buildings. This study examined temperature and relative humidity （RH） changes in typical residential and office buildings. The results indicate a relatively stable temperature with vary range of-4-1~C and a fluctuation RH trend which is similarly to that of water use. We proposed the concept of building water dissipation to describe the transformation of liquid water into gaseous water during water consumption and to develop a building water dissipation model that involves two main parameters： indoor population and total floor area. The simulated values were verified by measuring water consumption and water drainage, and the resulting simulation errors were lower for residential than for office buildings. The results indicate that bathroom vapor accounts for 70% of water dissipation in residential buildings. We conclude that indoor humidity was largely a result of water dissipation indoors, and building water dissipation should be considered in urban hydrological cycles.
