Dominik André Strebel

Last Name

Strebel

First Name

Dominik André

ORCID

0000-0002-3529-1798

Organisational unit

03806 - Carmeliet, Jan / Carmeliet, Jan

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Publications1 - 10 of 25

Retrofitting parking lots to mitigate heat stress in an urban park: A numerical case study at microscale
Giroux-Gauthier, Léopold; Strebel, Dominik André; Wood, Sylvia L.R.; et al. (2026)
Urban Forestry & Urban Greening
Urban forests and vegetated parks in cities, such as in the St. Helene Island in St. Lawrence River in Montreal, may help to mitigate heat stress during heatwaves. In this paper, we study how retrofitting scenarios that increase canopy cover in parking lots via tree planting can improve the thermal comfort for pedestrians. Specifically, we investigate the influence of tree size and placement within the parking lot sites on the thermal comfort in four retrofitting scenarios. We use the numerical suite of models urbanMicroclimateFoam, which simulates microclimate conditions at a local scale (submeter scale) solving Reynolds-averaged Navier-Stokes (RANS) equations for non-isothermal air flow, heat and moisture transport and storage in porous urban materials, solar radiation and longwave radiative exchanges between sky and urban surfaces and vegetation. The canopy of the park is reconstructed from LiDAR data allowing for simulation of transpirative cooling, shading and wind drag effects due to vegetation. We base our simulation on a 2020 heat wave that occurred in the Montreal region. Simulation of the current situation shows strong thermal heat stress with UTCI (Universal Thermal Climate Index) values up to 37°C. The retrofit scenarios explore the effect of replacing the pavement of two parking lots with grass, and the addition of trees in different arrangements, varying their size and position. We found that replacement of part of the asphalt pavement with grass yields an overall UTCI reduction of 1.5 °C. Scenarios adding trees in different arrangements improve the thermal comfort locally by cooling up to 6.5 °C. The reduction in UTCI is shown to be most importantly caused by a reduction of mean radiant temperature due to shading from the added trees in the area.
Machine Learning Reveals the State of Intermittent Frictional Dynamics in a Sheared Granular Fault
Ren, Christopher X.; Dorostkar, Omid; Rouet-Leduc, Bertrand; et al. (2019)
Geophysical Research Letters
Impact of Tree Leaf Area Density on Cooling and Ventilation of an Urban Neighborhood
Kubilay, Aytaç; Strebel, Dominik André; Derome, Dominique; et al. (2023)
Journal of Physics: Conference Series ~ Proceedings of NSB 2023: 13th Nordic Symposium on Building Physics
The impact of trees during heat waves can be diverse, as their interaction with their surroundings depends on several parameters that modify shading, ventilation potential and transpiration rate. A multiscale coupled model is presented that allows the detailed analysis of the local impact of vegetation as a mitigation measure for urban heat islands. A case study is performed on an urban neighborhood in Zurich, Switzerland, with an aim to improve the understanding of physical processes in urban microclimate subjected to a heat wave. A parametric study presents the impact of varying the leaf area density (LAD) of the existing trees in the neighborhood. Comparisons of surface temperatures and rate of transpiration with available measured data show a good agreement. The results show that urban trees can reduce heat storage during the day due to shadowing, especially when they are in groups. The reduction in air temperature due to transpiration largely depends on LAD, wind-flow patterns and urban morphology. The results also indicate locations with an increase in air temperature due to the presence of trees.
Improved Meso- and Microscale Simulation of Outside Thermal comfort and Application in Buidling Physics
Strebel, Dominik André; Ding, Xiaotian; Zhao, Yongling; et al. (2025)
Lecture Notes in Civil Engineering ~ Multiphysics and Multiscale Building Physics. Proceedings of the 9th International Building Physics Conference (IBPC 2024). Volume 2: Urban Physics and Energy Efficiency
Thermal comfort in the urban environment is an essential factor for the health and wellbeing of the population during heatwaves. Maps of thermal comfort indices can give urban planners and governments necessary information to assess the local thermal conditions. We propose a new method to calculate UTCI using point cloud data and WRF mesoscale simulations as inputs. The SOLWEIG method is used to calculate mean radiant temperature on microscale by using detailed building geometry. We also propose a new method for SOLWEIG to calculate the wall temperatures. The application of this approaches is shown by a case study for the City of Geneva.
Effects of Urban Heat Islands during Heat Waves in Montreal Residential buildings
Strebel, Dominik André; Boudali Errebai, Farid; Kubilay, Aytaç; et al. (2022)
ASHRAE Topical Conference Proceedings: Suppl. Thermal Performance of the Exterior Envelopes of Whole Buildings XV International Conference
Mesoscale meteorological simulations of the urban climate in Montreal during the hot summer of 2020 are used to assess the impact of the urban heat island on thermal comfort and building cooling energy demand in typical residential buildings. A new approach based on the cooling degree-hours (CDH) is proposed to map the urban heat island (UHI) of Montreal, called ’cooling demand island’. In the UHI of Montreal, the total cooling degree-hours are 30% higher compared to the rural surrounding, equal to an average increase of 15% in cooling energy demand. During the 2020 summer, non-air conditioned residential buildings experience more than 50% of the time thermal discomfort indoor. During heatwaves, the cooling energy demand increases substantially (more than 50%), since the air temperature during these periods is on average more than 10 C higher compared to non-heatwave days. Building energy demand simulations using reference climate data underpredict the cooling energy demand substantially compared to local climate data collected during hot summers. The analysis shows that local urban climate data during hot summers with heatwaves has to be used to properly predict the cooling energy demand of residential buildings in cities.
Understanding the impact of heatwave on urban heat in greater Sydney: Temporal surface energy budget change with land types
Kong, Jing; Zhao, Yongling; Strebel, Dominik André; et al. (2023)
Science of The Total Environment
The impact of heatwaves (HWs) on urban heat island (UHI) is a contentious topic with contradictory research findings. A comprehensive understanding of the response of urban and rural areas to HWs, considering the underlying cause of surface energy budget changes, remains elusive. This study attempts to address this gap by investigating a 2020 HW event in the Greater Sydney Area using the Advanced Weather Research and Forecasting (WRF) model with 250-m high resolution. Findings indicate that the HW intensifies the nighttime surface UHI by approximately 4 °C. An analysis of surface energy budgets reveals that urban areas store more heat during the HW due to receiving more solar radiation and less evapotranspiration compared to rural areas. The maximum heat storage flux in urban during the HW can be around 200 W/m2 higher than that during post-HW. The stored heat is released at nightime, raising the air temperature in the urban areas. Forests and savannas have relatively lower storage heat fluxes due to high transpiration and albedo, and the maximum heat storage flux is only around 50 W/m2 higher than that during post-HW. In contrast, a negative synergistic effect is detected between the 2-m UHI and HW. This may be because other meteorological conditions including wind have substantial impacts on the air temperature pattern. The strong hot and dry winds coming from the west resulted in a higher air temperature in the western urban district, and intra-city disparities are higher. Meanwhile, the western forest area also experiences higher temperatures due to the westward winds. In addition, changes in wind direction alter the temperature distribution in the northern rural region. The findings of the present study may provide some insights into urban heat mitigation during HW.
Nonlinear impacts of urban size and vegetation cover on global surface urban heat: Insights from 6022 cities
Jiang, Song; Zhao, Yongling; Zhao, Lei; et al. (2026)
Remote Sensing of Environment
Urban overheating, a confluence of urban heat island and climate change, is escalating alongside the rapid global urbanization. While previous studies have examined how urbanization and vegetation influence surface urban heat islands (SUHI), their nonlinear effects across climate zones remain insufficiently understood. Here, we present a globally consistent assessment of 6022 cities using MODIS Aqua data (MYD11A2) from the summer of 2019, validated with multi-year records (2017–2021), through a self-developed, scalable SUHI quantification method that enables cross-climate comparisons. Our results reveal distinct rapid- and slow-growth zones in SUHI intensification with urban size, with the fastest increase occurring in small cities below the top 20% of global urban size. This uneven rise in SUHI intensity stems from the synergistic effects of urban expansion and vegetation loss. Vegetation cooling exhibits a clear saturation beyond an inflection point, with the equatorial zone showing both weaker cooling efficiency and earlier saturation onset. Using a dual-perspective framework that integrates absolute and relative temperature metrics, we further show that Global South cities experience compounded thermal stress—featuring not only 3.37 ± 0.14 °C higher absolute temperatures due to their geographical setting, but also 0.24 ± 0.05 °C greater SUHI intensity than cities in the Global North. Together, these findings demonstrate that the effectiveness of heat mitigation strategies varies across climates and urbanization stages, underscoring the heightened vulnerability of smaller cities and the need for context-specific, climate-sensitive planning interventions. This study provides a globally integrated yet regionally differentiated understanding of surface urban heat and establishes a planning-relevant framework to guide targeted and climate-sensitive urban heat mitigation strategies.
A WRF-UCM-SOLWEIG framework for mapping thermal comfort and quantifying urban climate drivers: Advancing spatial and temporal resolutions at city scale
Ding, Xiaotian; Zhao, Yongling; Strebel, Dominik André; et al. (2024)
Sustainable Cities and Society
The capability to evaluate city-scale outdoor thermal comfort is crucial for understanding the public's experience of heat stress, especially during heat waves. Nevertheless, there remains a methodological gap in accurately mapping thermal comfort with high spatial and temporal resolutions in complex urban environment and in quantifying the contributions of various urban climate drivers, such as sky view factors and tree canopy fraction. To bridge this gap, we propose an innovative WRF-UCM-SOLWEIG framework that couples a mesoscale model with an urban microclimate model. Specifically, it integrates the Weather Research and Forecasting model coupled with the urban canopy model (WRF-UCM) and the Solar and Longwave Environmental Irradiance Geometry model (SOLWEIG). This framework is then applied to a densely populated tropical city in China, to quantify the impact of urban climate drivers on the Universal Thermal Climate Index (UTCI). The results reveal a significant diurnal variation in the impact of urban morphology. Notably, the most significant drivers affecting daytime UTCI are the impervious surface fraction and the tree canopy fraction, with maximum Pearson's correlation coefficients of 0.80 and -0.70, respectively. These findings suggest that urban heat mitigation strategies should prioritize on reducing impervious surfaces and enhancing shade management, alongside expanding urban forestry measures.
Understanding cooling potential of urban trees in a typical North America neighborhood
Nevers, Clément; Carmeliet, Jan; Strebel, Dominik André; et al. (2025)
Building and Environment
Urban areas are experiencing rising temperatures leading to the exploration of mitigation solutions to cool cities. Common solutions rely on trees. However, trees can both enhance and deteriorate pedestrian thermal comfort in different areas of a neighborhood and at different times of the day. The objective of this paper is to document and quantify the overall contribution of trees to the pedestrian comfort in an entire neighborhood, with a special attention to cooling. Various vegetation scenarios are applied for a typical North American urban neighborhood, inspired by a neighborhood in Montreal, during a heat-wave period. The study focuses on 6 central urban lots including alleys, streets and a large boulevard, forming an area of 250 m x 300 m, surrounded by 14 urban lots. We use all-physics computational modeling to assess the multifaceted effects of trees at urban scale, using a custom CFD-based coupled solver developed by the authors, urbanMicroclimateFoam, based on OpenFOAM. This urban microclimate model sequentially solves turbulent air flow, heat and moisture transport in porous media, and radiative exchanges. The Universal Thermal Climate Index (UTCI) is used to document outdoor thermal comfort. The analysis reveals that trees in ventilation corridors, i.e. streets aligned with the primary wind, reduce average pedestrian comfort in the neighborhood by blocking wind despite providing shade. Conversely, trees in private gardens or in crosswind corridors can enhance both local thermal comfort and overall average pedestrian comfort throughout the neighborhood, thereby improving walkability. The paper highlights the non-local effects of trees over the entire neighborhood.
Changing Urban Climate and Its Mitigation: An Explicit Urban Climate Simulation Approach
Carmeliet, Jan; Nevers, Clément; Strebel, Dominik André; et al. (2026)
Lecture Notes in Civil Engineering ~ Proceedings of CESBP 2025 - 6th Central European Symposium on Building Physics, Volume 2
A multiscale urban climate modeling approach is used to study the urban climate at both city and neighborhood scales. The mesoscale meteorological model WRF (Weather Research and Forecasting), enhanced with urban land use parameterization, simulates the urban microclimate in Geneva and Fribourg, Switzerland, during the summer of 2019. Heat exposure indices are mapped to quantify the urban heat island (UHI) effect and identify multiple hot spots, enabling the selection of a representative heatwave for detailed microscale analysis. Microscale simulations are conducted using urbanMicroclimateFoam, a open-access numerical model developed by the authors based on OpenFOAM. These simulations are driven by boundary conditions from the mesoscale WRF outputs. The microscale study focuses on the Schoenberg neighborhood in Fribourg, analyzing current conditions and three future scenarios: densification, increased vegetation, and a combined Eco-city scenario. Densification generally increases air temperature and worsens thermal comfort due to reduced wind flow and increased heat from sunlit building facades. However, some areas benefit from additional shading and cooler downdrafts from taller buildings. The Eco-city scenario demonstrates that adding vegetation can mitigate the negative impacts of densification. Shading from trees and evapotranspiration contribute to lower temperatures and improved comfort. Nonetheless, in areas where ventilation is hindered, thermal comfort can deteriorate compared to the present situation. These findings highlight the importance of strategic planning in urban design. Incorporating vegetation thoughtfully can offset some adverse effects of densification and support climate-resilient urban development.

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Dominik André Strebel

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