Towards understanding implications of urbanization for regional and global climate in the GFDL Earth System Modeling framework

Abstract:

Land-use/land-cover changes at regional and global scales have been shown to play an important role in altering the climate, the hydrological cycle and the biogeochemical cycle. Urbanization is an extreme case of land-use/land-cover change through which natural surfaces are transformed into man-made surfaces. How urban areas affect regional and global climate and equally importantly, how urban areas respond to climate change at different time scales (ranging from seasonal to decadal) are critical areas of research. However, to date, most global climate and earth-system models that are used to investigate impacts of land-use/land-cover changes on the climate do not include an urban representation. Moreover, the dynamic growth and changes of urban areas (e.g., transformations of cropland to urban land) are not considered in any existing urban representations. In order to answer the questions raised above, the Geophysical Fluid Dynamics Laboratory (GFDL) has developed a high-resolution global climate model with an urban representation that can simulate interactively both changes in urban environments and feedbacks of urban changes. In this study, efforts towards urbanizing the Geophysical Fluid Dynamics Laboratory (GFDL) land model LM3 are described. In addition, historical simulations with the urbanized GFDL LM3 are used to investigate how the growth of urban areas has affected the near-surface climate in recent decades.