Relationship between Urbanization and Climate Change in South China

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Relationship between Urbanization and Climate
Change in South China

• Johnny Chan
• City University of Hong Kong

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Outline

• Background
• Objectives, long-term goals and vision
• Research methodology

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Background
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Guangzhou
Hong Kong
Urban Area
vs. Farmland
Shenzhen
Farmland in Guangdong
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Urban or Built-up Area in the Pearl River Delta
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Effects of Urbanization on Climate
Emission of atmospheric pollutants
Changes in cloud condensation nuclei concentration
Changes in cloud amounts and hence rainfall
Changes in radiation budget
Urbanization
Heat Island Effect
Changes in runoff patterns and momentum fluxes
Changes in land use
Changes in heat and moisture fluxes
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Land-sea Breeze Circulation
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HK temperature
No. of haze days in Guangzhou
HK solar radiation
Climate Change in the PRD (related to radiation)
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PRD relative humidity
PRD rainfall
Climate Change and Urbanization in the PRD
(related to water)
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winter
Projected Patterns of Precipitation Changes
summer
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Objectives, Long-term Goals and Vision
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Objectives

• To understand the effects of urbanization and
  their relative contributions on the observed
  climate change in the Pearl River Delta region
• To estimate what might be expected in the future
  given current projections of changes in
  urbanization

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Long-term Goals
Improved understanding of how urbanization has
contributed towards the climate change of a region
Science
Improved understanding of the effects of various
components of urbanization, and thus how they
might be better represented in the models
To provide useful information for government
planners as to how they can achieve a balance
between economic development in terms of
urbanization and changes in the climate
Applications
To estimate consequences of local climate change
if current developments are to continue so that
adaptation strategies could be developed
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Research Methodology
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Observational Stations in PRD
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Chemical Transport Model(Models-3/CMAQ model)
Emission Modelling system
Chemistry processor
Meteorology Modelling system
Meteorology- Chemistry interface Processor
Advection processor
Hourly gridded concentrations for species of
interest
Diffusion processor
Photolysis rates processor
Cloud processor
Initial condition processor
Aerosol processor
CMAQ Chemical Transport Model (CCTM) Processor
Boundary condition processor
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Land Surface Model
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Land Surface Model (LSM)
Rainfall simulation over South China by coupling
the LSM and a global climate model (GSM)
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Preliminary Results of Model Simulations of the
Effect of Urbanization
Effect of increasing the roughness of the Earths
surface on rainfall
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Preliminary Results of Model Simulations of the
Effect of Urbanization
Effect of turning off the moisture flux on
rainfall
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Thank You