TY - JOUR
T1 - Urban water capacity
T2 - Irrigation for heat mitigation
AU - Wang, Chenghao
AU - Wang, Zhi Hua
AU - Yang, Jiachuan
N1 - Funding Information:
The authors would like to acknowledge high-performance computing support from Cheyenne provided by National Center for Atmospheric Research 's Computational and Information Systems Laboratory , sponsored by the U.S. National Science Foundation .
Funding Information:
The authors would like to acknowledge high-performance computing support from Cheyenne provided by National Center for Atmospheric Research's Computational and Information Systems Laboratory, sponsored by the U.S. National Science Foundation.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/11
Y1 - 2019/11
N2 - Our world has been continuously urbanized and is currently accommodating more than half of the human population. Despite that cities cover only <3% of the Earth's land surface area, they emerged as focal points of human activities, and confront numerous environmental challenges as a result of changes in landscapes, hydroclimate, ecosystems, and biodiversity. In particular, the built environment usually experiences exacerbated heat stress induced by global climate and landscape changes, commonly known as the urban heat island effect. Urban irrigation, as a climate adaptation and mitigation strategy, is effective in cooling the built environment, but exhibits large uncertainties in the trade-off between water use and heat mitigation capacity. Here we show the efficiency of cooling effect induced by irrigation of urban vegetation, represented by a novel metric, viz. urban water capacity, analogous to the heat capacity, across the contiguous United States (CONUS) during summertime via numerical simulations. The urban water capacity is calculated as the average irrigation depth per degree of urban temperature reduction; the values are 4.52 ± 0.77 mm day−1 °C−1 and 7.27 ± 1.27 mm day−1 °C−1 (mean ± standard deviation) for surface and near-surface air cooling, respectively, over the CONUS. The robustness of urban water capacity is further exemplified in an extreme heat wave event, during which the warming anomaly is partially offset by the additional cooling from urban irrigation. Estimates of water capacity provide a quantitative metric for evaluating the efficacy of irrigation in urban planning under current heat stress and future warming.
AB - Our world has been continuously urbanized and is currently accommodating more than half of the human population. Despite that cities cover only <3% of the Earth's land surface area, they emerged as focal points of human activities, and confront numerous environmental challenges as a result of changes in landscapes, hydroclimate, ecosystems, and biodiversity. In particular, the built environment usually experiences exacerbated heat stress induced by global climate and landscape changes, commonly known as the urban heat island effect. Urban irrigation, as a climate adaptation and mitigation strategy, is effective in cooling the built environment, but exhibits large uncertainties in the trade-off between water use and heat mitigation capacity. Here we show the efficiency of cooling effect induced by irrigation of urban vegetation, represented by a novel metric, viz. urban water capacity, analogous to the heat capacity, across the contiguous United States (CONUS) during summertime via numerical simulations. The urban water capacity is calculated as the average irrigation depth per degree of urban temperature reduction; the values are 4.52 ± 0.77 mm day−1 °C−1 and 7.27 ± 1.27 mm day−1 °C−1 (mean ± standard deviation) for surface and near-surface air cooling, respectively, over the CONUS. The robustness of urban water capacity is further exemplified in an extreme heat wave event, during which the warming anomaly is partially offset by the additional cooling from urban irrigation. Estimates of water capacity provide a quantitative metric for evaluating the efficacy of irrigation in urban planning under current heat stress and future warming.
KW - Extreme heat wave
KW - Heat mitigation
KW - Irrigation
KW - Regional hydroclimate
KW - Urban water capacity
KW - Water–heat trade-off
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U2 - 10.1016/j.compenvurbsys.2019.101397
DO - 10.1016/j.compenvurbsys.2019.101397
M3 - Article
AN - SCOPUS:85071397242
SN - 0198-9715
VL - 78
JO - Computers, Environment and Urban Systems
JF - Computers, Environment and Urban Systems
M1 - 101397
ER -