LUCRETIA
The role of Land Use Changes on the development of intra-urban heat islands.
The aim of the LUCRETIA project was to analyse intra-urban temperature variability based on different urban climate models and crowdsourced observational data. In addition, various existing LU/LC data sources were analysed and integrated into urban climate models to assess their impact and influence on temperature patterns in urban areas and thus determine uncertainties. In addition, historical LU/LC datasets were used to analyse changes in urban structure and to assess the long-term climatic impacts resulting from LU/LC modifications using an urban climate model.
The evaluation of model results on intra-urban variability of hourly air temperatures was performed for a selected 3-day period during a heat wave in 2018. Two modeling approaches, urban climate model MUKLIMO_3 and the newly developed PALM-4U model were compared. The simulations were performed on a city and district scale with spatial resolution varying between 10 m and 100 m. The observational data used to evaluate the models included measurements from operational weather stations and quality-checked data from an online available network of private weather stations of the company NETATMO. The results showed generally similar model performance, confirming that both models are well suited for the urban climate applications. However, the higher-resolution PALM-4U model enabled a more detailed analysis of inner-city temperature fluctuations and allowed a better identification of hot/cool zones in the city.
The analysis of LU/LC changes based on historical data for Vienna (1981–2005) and Graz (1952–2004) showed progressive urbanization in both cities, in particular through the transformation of agricultural land into building and traffic areas. The model simulations with historical LU data confirm that the changes in the LU/LC can have a positive or negative impact on the heat load. The changes in heat load are strongest locally, but warming or cooling effect can be found in the surrounding area, however with less intensity and with limited spatial extent. The results of the projects improved the current understanding of LU/LC changes and their impact on urban climate in Vienna and Graz.