NVIDIA x Sia Partners Exclusive Event
A Study on Urban Heat Islands
Urban Heat Island (UHI) refers to an elevation in both air and surface temperatures within metropolitan regions when compared to surrounding or rural areas. Could satellite imaging hold the solution to this warming effect?
The urban heat island (UHI) effect refers to a notable elevation in both air and surface temperatures within metropolitan regions when compared to the surrounding or rural areas. As urban areas continue to expand and global temperatures rise, the impact of UHIs on cities has become increasingly significant, with consequences in multiple sectors, from public health and energy consumption to the very conception of urban planning and design. In this context, detecting UHIs and understanding how they affect cities has become critical for policymakers, urban planners and communities striving to ensure more resilient urban spaces that are fit to live in.
Satellite images could help identify solutions
Considering the importance of this phenomenon and its implications for urban environments, Sia Partners has developed a methodology for analyzing satellite images to identify and characterize UHIs to better understand the existing situation and facilitate decision-making.
To this end, we have written two whitepapers that provide a comprehensive understanding of the subject. In the first whitepaper (only available in French), we delve into the causes and effects of heat islands, examining the factors that contribute to their formation and the subsequent impacts on human health, energy consumption, and overall urban climate.
Additionally, we explored the potential mitigation strategies that can be employed to alleviate the adverse effects of heat islands. We also briefly explained how an efficient mobilization of artificial intelligence can allow us to better understand the situation on a local scale and support the political decision-making to address it.
In this second whitepaper, we focus on the technical aspects behind the unsupervised remote detection of UHIs. This includes an explanation of the following operations:
- Landsat 8 images pre-processing.
- Land Surface Temperatures (LSTs) computation and mapping.
- LST threshold computation using heat distribution analysis.
- UHI grouping and identification using the Connected Component Analysis (CCA) method on the mask image created using the LST threshold.
- UHI analysis and characterization.
Additionally, we highlight how we can use these detections to compute vulnerability indices that are useful for urban planning and public health interventions.
Finally, we explain how we used our UHI detection tool to assess the effectiveness of specific countermeasures against UHIs in the context of the Oasis project, a project funded by the European Union's "Innovative Urban Actions" initiative. This tool was used to analyze the thermal evolution of the Tandou and Emeriau kindergartens, both project members. With the use of data collected before and after the implementation of the innovative solutions, we were able to assess the success of these measures in mitigating UHI effects and contributing to more sustainable and comfortable urban environments.
