Investigating the Direct and Indirect Impacts of Global Urban Expansion on Future Climate Using a Dynamic Urban Scheme
Abstract
Urbanization influences local climate directly by modifying surface biophysical properties. Large-scale urban expansion may also impact local and regional climate indirectly via atmospheric feedback. So far, no quantitative evaluation is available on these two urban climatic impacts because current climate models cannot simulate urbanization expansion. This impedes an accurate assessment of future climate under the combined effect of urbanization and greenhouse gases.
The goal of this research is to investigate the direct and indirect impacts of urban expansion on climate under the SSP5-8.5 scenario. We will use a new dynamic urban scheme implemented in NCAR's Community Earth System Model. Two sets of fully-coupled simulations will be run from 2015 to 2070, one with annual urban growth projected for the SSP5 scenario and the other with urban land use fixed at the 2015 level. To reduce internal model variability, each set will consist of three realizations. Two sets of offline simulations will be carried out to help isolate the direct and the indirect impact of urban expansion on surface climate. One set of offline simulations will have the urban land use fixed at the 2015 level and the other will allow urban land to grow annually, and both will be driven by the SSP5-8.5 atmospheric forcing. Using ensemble mean results, we will examine the relative contributions of direct and indirect effects to the screen-height temperature changes and elucidate processes that initiate the indirect effect. We will compare and contrast the role urban expansion plays in future climate projections at local, regional, and global scales.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMGC42U0965Z