Urbanization Impacts on Evapotranspiration Across Various Spatio-temporal Scales

The data in this release describe various aspects of the impacts of urbanization on evapotranspiration at local to global spatial scales. This data release is associated with the publication of these results in a concurrent journal article. Analyses in the journal article included comparisons between urban and non-urban ET in a variety of climate settings and spatial scales. Urbanization has been shown to locally increase the nighttime temperatures creating urban heat islands, which partly arise due to evapotranspiration (ET) reduction. It is unclear how the direction and magnitude of the change in local ET due to urbanization varies globally across different climatic regimes. This knowledge gap is critical, both for the key role of ET in the water cycle accounting for the majority of local precipitation, and for the high socioeconomic value of urban landscapes, where water resources are often in high demand. We explore and assess the impacts of urbanization on ET across a range of landscapes from local to global spatial scales, and monthly to mean annual timescales. Remotely sensed land cover and ET available at 1 km resolution are used to quantify the differences in ET between urban and surrounding non-urban areas across the globe. The observed patterns show the difference between urban and nonurban ET can be estimated to first order as a function of local hydroclimate with arid (humid) regions seeing increased (decreased) ET due to urbanization. Cities under cold climates also evaporate more than their non-urban surroundings during the winter as the urban micro-climate has increased energy availability resulting from human activity. Increased ET in arid cities clearly arises from municipal water withdrawals and increased irrigation during drought conditions further increases the ET from arid urban cities compared to non-urban ET. This information can help to inform planners for improved environmental conditions in designing urban landscapes. This data set will be updated with the full journal article citation when available. See also the metadata file for additional information, or contact the authors with questions.