THESIS
2022
1 online resource (xviii, 146 pages) : color illustrations, color maps
Abstract
Both greenhouse gas (GHG) emissions and urban expansion are regarded as important
contributors to accelerating warming trends. Southeastern China, where Pearl River Delta
(PRD) and Yangtze River Delta (YRD) are nestled, is a representative region with mounting
concerns related to anthropogenic warming and the rapid pace of urbanization. Since these
places have already experienced thermal discomfort at dangerous levels, it is not farfetched to
infer that further warming will increase the heat stress close to the lethal level of human
adaptability. However, most climate projections are yet to adequately consider future urban
growth and their synergistic effects under global warming, leading to a potential
underestimation of the risk of heat-related extremes. This study adopts the latest v...[
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Both greenhouse gas (GHG) emissions and urban expansion are regarded as important
contributors to accelerating warming trends. Southeastern China, where Pearl River Delta
(PRD) and Yangtze River Delta (YRD) are nestled, is a representative region with mounting
concerns related to anthropogenic warming and the rapid pace of urbanization. Since these
places have already experienced thermal discomfort at dangerous levels, it is not farfetched to
infer that further warming will increase the heat stress close to the lethal level of human
adaptability. However, most climate projections are yet to adequately consider future urban
growth and their synergistic effects under global warming, leading to a potential
underestimation of the risk of heat-related extremes. This study adopts the latest version of the
Regional Climate Model (RegCM) for dynamical downscaling to better resolve geographically
diverse climate features and then address the aforementioned limitations. Its performance has been improved by optimizing the configurations over target domains and incorporating a new
urban module. First, the double-nested modeling system is developed focusing on the PRD and
YRD regions, and its capability to capture region-specific climate characteristics is intensively
evaluated in order to assess the effects of convection-permitting and non-hydrostatic dynamical
core. Then, the land surface parameterization in RegCM is improved by incorporating a
building energy model to prognostically account for the interior building temperatures, thereby
enhancing the estimation of released anthropogenic heat fluxes into the urban canopy. Finally,
the multiple global climate projections forced by both medium as well as high levels emission
scenarios (i.e., RCP4.5 and RCP8.5) are dynamically downscaled using RegCM double-nested
system with the improved urban parameterization by prescribing future urban expansion
generated from different Shared Socio-Economic Pathways (i.e., SSP2 and SSP5). The
comparative analysis of downscaled results over the PRD and YRD regions will provide
valuable insights into the dominance of varied physical processes acting on the targeted
domains as well as the severity of the negative impacts of future warming on human thermal
comfort.
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