Urban water capacity: Irrigation for heat mitigation

Chenghao Wang, Zhihua Wang, Jiachuan Yang

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Article number101397
JournalComputers, Environment and Urban Systems
Volume78
DOIs
StatePublished - Nov 1 2019

Fingerprint

irrigation
heat
mitigation
water
cooling
warming
climate
heat island
heat capacity
landscape change
urban planning
trade-off
water use
global climate
land surface
human activity
surface area
biodiversity
urban water
anomaly

Keywords

  • Extreme heat wave
  • Heat mitigation
  • Irrigation
  • Regional hydroclimate
  • Urban water capacity
  • Water–heat trade-off

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Ecological Modeling
  • Environmental Science(all)
  • Urban Studies

Cite this

Urban water capacity : Irrigation for heat mitigation. / Wang, Chenghao; Wang, Zhihua; Yang, Jiachuan.

In: Computers, Environment and Urban Systems, Vol. 78, 101397, 01.11.2019.

Research output: Contribution to journalArticle

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