A Perspective (1960-2030) of Hong Kong's Urban Development and Urban Climate - a Historical Context for Future Actions (14611015) (Completion Date: 30 Jun 18)
• Researchers: REN Chao, HUANG Bo, Steve YIM
• Funding Amount: HK$573,000
• Funding source: Research Grants Council - General Research Fund

The 50-year history of new towns and major urban developments in Hong Kong has seen the growth of the city with the highest population density in the world. In the process, it has created unique urban morphological forms that have inevitably changed the local urban climatic conditions (Lam, 2006; Lau & Ng, 2013). Understanding the urban climatic changes of the urban forms in the past allow planners have the perspective for gaining an insight into the future. It also allows decisions on future development to be made in context. This study aims to trace, from a historical perspective, the influences of new towns and major urban developments in Hong Kong on its local urban climatic conditions. It then further aims to investigate the relationship between the urban morphology of the high density city and its urban climatic characteristics in the future. This study firstly collects historical records (1960-2010) on Hong Kong's land-use data from the Lands Department of the Hong Kong Government (LandsD). Major urban growth periods can be time sequenced. Secondly it employs a digitizer to get digitalized land-use data in the Geography Information System (GIS) (Rumsey and Williams, 2002); then, future land use changes (until 2030) can be statistically predicted by using Change Analyst (Huang & Sin, 2010). In the meanwhile, meteorological records (1960-2010) are acquired from the Hong Kong Observatory (HKO) and the linear regression method called JMP 0.9 Statistical Package can be adopted to separate urbanization effect and climate change for the past. Furthermore, this will be coupled to the climate change projections of the global climate models (GCMs) from the fifth phase of Climate Model Intercomparison Project (CMIP5) for the future climatic conditions to the year 2030. The urban morphological and climatic data sets are then be entered into the Weather Research and Forecasting with an Urban Canopy Model (WRF-UCM). Based on principle component analysis (PCA), the relatively importance of planning parameters like Frontal Area Density (FAD), Ground Coverage Ratio (GCR), Plot Ratio (PR), of urban forms may be understood. This understanding of the time series and component based relationship between urban forms and urban climatic condition provides a reference for the planners on which planning parameter to optimise for the future. This is important for planners of high density cities in the tropical regions – especially when they are working at the thresholds of heat stress and urban thermal comfort issues.

The objectives of this study are: (A) to collect and collate historical records (1960-2010) on Hong Kong’s land-use data from the LandsD and meteorological records from HKO; (B) to determine major urban growth periods from 1960-2030 and statistically calculate typical summer condition for each period; (C) to statically predict future land-use changes (until 2030) by using Change Analyst and to adopt to the climate change projections of the global climate models (GCMs) from the fifth phase of Climate Model Intercomparison Project (CMIP5) to the year 2030 future urban climatic condition; (D) to run a series of WRF-UCM simulations to get a chronological perspective on the effects of Hong Kong's new towns and new major urban developments on its urban climatic conditions; (E) to conduct parametric tests using the planning parameters extracted from WRF-UCM simulations and run principle component analysis (PCA) to identify and understand from a climatic point of view the relatively importance of planning parameters like Frontal Area Density (FAD), Ground Coverage Ratio (GCR), Plot Ratio (PR) of urban forms; (F) to develop a set of planning recommendations and design guidelines which can guide town planners and governors in designing better town developments and urban renewal in the future.