A "Local Climate Zone" based approach to urban planning in Colombo, Sri Lanka

Manipulating the urban fabric is fundamental to managing the warming trend in the growing high-density tropical settings to both mitigate the negative consequences as well as adapt cities to live with these changes. However, the current planning regime is yet to address the challenges posed by local, regional and global warming.

An in-depth understanding of the interaction between the physical form and the climatic context is crucial for the generation of climate sensitive urban planning approaches. However, data needs and methods of analysis remain problematic at present to achieve this.

In this paper we showcase a simpler method of contextual analysis using the Local Climate Zone (LCZ) system in warm humid Colombo, Sri Lanka. Mean Radiant Temperature (MRT) – key variable in outdoor thermal comfort at street level – is linked to urban indicators encompassing geometric and surface cover characteristics in the LCZ classification, together with climate variables generated by the use of the microclimate simulation model ENVI-met. The simulations include a series of LCZ-based morphology options to reduce MRT in the urban outdoors at present and in a future warm scenario. Statistical analyses of the results test the applicability and sensitivity of urban morphological variables to help mitigate / adapt to local and global warming.

The work contributes towards a deeper understanding of the effect of building morphology on local level warming, with minimal data input. This could help develop climate-sensitive planning and policy in warm humid climates.