1,2,- 1Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland (moritz.burger@unibe.ch)
- 2Institute of Geography, University of Bern, Bern, Switzerland
- 3Institute for Lower Secondary Education, Bern University of Teacher Education, Bern, Switzerland
- 4Chair of Climatology, Institute of Ecology, Technische Universität Berlin, Berlin, Germany
In recent years, different models to simulate urban climate variables have been applied to cities around the world to model, among other variables, the intra-urban air temperature variabilty. Since the modeling of urban climates is complex and subject to resulting uncertainties, validation of the model outputs with in-situ data is crucial. However, intercomparing different urban climate models remains challenging, since they are usually applied to different study areas with varying input data and specific research questions.
In the city of Bern, Switzerland, four urban climate models have been applied recently. This includes a geostatistical land use regression model (LUR) and the numerical model MUKLIMO_3, which were run by the University of Bern, and the numerical models PALM and FITNAH 3D which were set up by private companies (Meteotest AG and GEO-NET Umweltconsulting GmbH). Although the different stakeholders used varying model domains, study periods, and spatiotemperoral resolutions, an intercomparison of the nighttime intra-urban air temperature variability was enabled using air temperature data from 70 stations of an urban air temperature measurement network.
In our study, we compare the outputs of the models with measured data of a specific (which was modeled by LUR, MUKLIMO and PALM) and an average heat night (similar to the FITNAH scenario). Our analysis reveals that MUKLIMO_3 outputs show a weak urban air temperature variability for the city of Bern, while strong small-scale temperature gradients are modeled by FITNAH 3D. PALM outputs are the only ones that reproduce the impact of a large-scale ventilation pattern, but have in general a large positive bias. The most accurate estimates of the urban air temperature variability are obtained from the LUR model. For future applications of urban climate models, we reinforce the need of validation with in-situ measurements, since the outputs (and subsequent policies) depend substantially on the selection of the model.
How to cite: Burger, M., Gubler, M., Holtmann, A., and Brönnimann, S.: Spoilt for choice - Intercomparison of four urban climate models , 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-78, https://doi.org/10.5194/icuc12-78, 2025.
Supporters & sponsors
