An investigation of urbanization effect on urban and rural Hong Kong using a 40-year extended temperature record

• The study supplements past climate at district level without observed records.
• Warming trends are particularly observed in rural stations.
• Baseline conditions are provided for future temperature projection under different scenarios.

The effects of climate change on air temperature are often described at a global scale as described by the near-surface air temperature on annual basis. As people are intrinsically affected by local climate, it is important to describe climatic variations on regional to local scales in order to provide information to government authorities and associated parties to assist urban planning and design for adaptation measures in the future. The present study aims to extend the past temperature record of designated meteorological stations in Hong Kong using regression techniques in order to supplement the understanding of past climatic conditions at district level where observational records are generally lacking. Warming trends are generally observed and the rate of warming is particularly observed in rural stations. Such a trend is associated with land conversion into concrete surface in surrounding areas and reduction in vegetation cover. Cooling was experienced in the last decade because of the cease of urbanization and the canyon effect present in highly compacted urban environment. Findings of the present study contribute to the understanding of the effect of climate change on areas with various land use and provide baseline conditions for temperature projection of future climate change scenarios. Such information will be useful to the incorporation of microclimatic conditions into the urban planning and design framework, especially for potential development in country areas and redevelopment of inner urban areas in the future.