Author(s):
Johannes Feddema* - University of Kansas
Abstract:
Urban systems have a significant effect on the disposition of energy and water in an environment. While this locally significant climate effect only impacts a small area of the land surface, it has a direct impact on roughly half the human population. By simulations the combined effects of urbanization and larger scale climate changes from land cover change and atmospheric composition, we can now assessed for different locations climate impacts on specific human population sectors (e.g. high residence urban or sub-urban populations).
This paper will qualitatively assess the effectiveness of an urban canyon type model in the National Center for Atmospheric Research (NCAR) Community Climate System Model (CCSM) to simulate typical urban heat islands over the contiguous US. We test the robustness of the model through sensitivity studies and evaluate the model's ability to simulate urban heat islands in different environments. Findings show that heat storage and sensible heat flux are most sensitive to uncertainties in the input parameters within the atmospheric and surface conditions considered here. Sensitivity studies suggest that attention should be paid to not only accurately characterizing the structure of the urban area, but also to the input data reflecting the thermal admittance properties of city surfaces. The magnitude and timing of the heat island varies tremendously depending on the prevailing meteorological conditions and the characteristics of surrounding rural environments.
