As extreme weather events increase it’s vitally important to identify populations who are vulnerable to extreme heat, particularly those living in urban areas. Many urban areas have higher temperatures than rural areas, a direct result of urbanisation, which is referred to as an ‘urban heat island’. This is even more crucial in Australian context, which will experience an increasing frequency of heatwaves in the coming years.
Higher urban temperatures can impact communities in a number of ways—compromising health, increasing energy consumption, impairing air and water quality—and there is an increasing need to identify the causes of urban heat islands. While there is a correlation between green spaces and lower urban temperatures, urban planners need more precise data and tools to effectively develop urban green spaces as a means of protecting urban dwellers from heat and generating local cooling effects.
The Integrated Heat Vulnerability Assessment Toolkit for Australian Cities (iHVI) is led by Dr Chayn Sun from RMIT University and is funded by the AURIN High Impact Projects program. The aim of the project is to establish a nationwide, dynamic and interactive heat vulnerability assessment toolkit. The toolkit will have enhanced workflow, automated analysis, and modelling tools. The indicators and indices will be able to be updated and constructed by the users to serve more applications. The objectives of the iHVI project are to:
- Develop tools to derive land surface temperature and classify landcover types via Google Earth Engine (GEE) API.
- Develop tools to construct heat sensitivity, heat adaptive capability indicators, and composite heat vulnerability index based on Intergovernmental Panel on Climate Change (IPCC) vulnerability assessment framework.
- Provide spatially explicit implications of reducing heat risk at the community level to support governments’ decision making.
The iHVI Toolkit will use open source or publicly available government data as the source dataset and will develop new tools using Python and Javascript libraries. Satellite imagery will be accessed from the Google Earth Engine platform, including:
- Landsat-8 and MODIS thermal imagery, used to derive high spatial-temporal resolution and fused land surface temperature and urban heat island effect using machine learning.
- Sentinel-2 imagery, used to extract impervious surface and vegetated areas by image segmentation using machine learning.
This project will develop a method to identify streets and neighbourhoods that require climate mitigation, which will contribute to sustainable development and achieve Goal 11 (Sustainable Cities and Communities) of the United Nations’ Sustainable Development Goals (SDG). The index and indicators of heat will be critical information for city planners and decision makers to use as benchmarks and guidance in climate change mitigation planning and city design.
Six months into the project Dr Chayn and her team have derived nation-wide SA1 datasets, developed from Google Earth Engine. The team compiled a series of JavaScript codes using open source data to derive earth observation datasets.
The team has also developed an iGEE toolkit and the iHVI desktop toolkit. The iGEE webtool enables data processing in the cloud without downloading data to a local environment and writing codes to process the datasets. The iHVI toolkit can automatically retrieve data via the AURIN API and the iGEE webtool. The toolkit will be able to process six parameters—population density, percentage of age-over-65, percentage of age-under-4, percentage of population needs care, education level, income level, as well as computing heat exposure, heat sensitivity, and adaptive capability indicators for a composite Heat Vulnerability Index (HVI)—in a few clicks, without coding and analytic requirements.
The iHVI project is an AURIN High Impact Project (HIP). Through the HIP program, AURIN engages with Australian urban, regional and social planning communities—including researchers, planners and policy makers from academic, government, NGO/NFP and private sector organisations—through collaboration and co-investment in high-quality, high-priority, high impact projects.
The iHVI project will deliver new datasets, tools, and services, while demonstrating the value and potential of its use within the AURIN Platform. This project is expected to put Australia at the frontier of heat vulnerability research, something that is of critical importance to the nation. The toolkit will contribute to sustainable development in many cities, leading to shadier streets, increased active travel, and significant health benefits for the community.
A 2018 version of Dr Chayn’s project, known as the Heat Vulnerability Index (HVI), has already been used by local governments across Melbourne, Dandenong, and Bendigo, resulting in increased tree plantings in heat sensitive urban areas. Once the iHVI project is complete, users of the toolkit will have access to even more datasets with expanded parameters, allowing for a more comprehensive understanding of urban heat island vulnerabilities and the populations that inhabit them.