Urban Cooling by Trees – Assessing and Modeling for Designing Sustainable Cities

Informations

Funding country

France

Acronym

COOLTREES

URL

-

Start date

1/1/2017

End date

-

Budget

349,930 EUR

Fundings

Abstract

Among adaptation strategies of cities to climate change and especially to extreme heat events, « greening » cities, i.e. reintroducing vegetation within cities is probably a promising way since vegetation through transpiration and shading has a significant impact on the heat balance of the surrounding atmosphere. This positive impact is strengthened by ecosystem services that could provide vegetation and especially trees, to inhabitant: environmental clean-up (air and soil), carbon sequestration, social well-being, and biodiversity. Trees by their structure could provide a high level of service in terms of shading and cooling via the evapotranspiration process. Several kinds of models have been developed so far to simulate the interactions between trees and urban climate by adding a specific module to urban climate models. However the resolved spatial scale of urban climate models is usually larger than 100m. This disables an accurate representation of the spatial arrangement of trees and buildings at the canyon scale and theirs interactions with the atmosphere. As a consequence, and because of the sensitivity of the latent heat flux to the representation of the tree structure, the latent heat flux is not properly simulated in urban climate models. The general objective of COOLTREES is to assess and model the evapotranspiration of urban trees in relation with their environments, and to relate their role in the urban climate with their structural and functional traits. To scale-up the latent heat flux from the tree scale to urban scale, three different models, associated to that three spatial scales, will be investigated and interconnected through the project: the RATP model (the tree scale), the LASER/F model (the canyon scale) and the SURFEX model from MESO-NH model (the city scale). The simulation outputs will be assessed from data acquired from on ongoing experiments in the city of Strasbourg. The duration of the project is 36 months and will gather four complementary partners. Two research teams, UMR PIAF INRA/Université Clermont Auvergne, and UMR ICUBE CNRS/ Université de Strasbourg/INSA/ENGEES, and the engineer services of the city of Strasbourg. Together, they cover all the scientific and technical fields of the project: from plant biology (UMR PIAF) to urban climate modeling and remote sensing (UMR ICUBE), and urban planning through local policy-makers (mairie de Strasbourg). The “Plante et Cité” association is also involved in the project and will promote interconnexion of the project and dissemination of the results to other actors involved in the topic of the development of urban vegetation.