The Local Climate Zones are known to have significant and distinct thermal environment; however its spatial pattern also determines the thermal characteristics of an area. The purpose of this study is to investigate relationship between landscape patterns of Local Climate Zones and its impact on thermal environment measured here as Land Surface Temperature (LST), taking a case of city of Bhopal, in India. Bhopal has an overall 9 LCZ classes. Three LCZs - compact low-rise areas (LCZ-3), Open low-rise (LCZ-6) and sparsely built (LCZ-9) (p <0.05) makes up the majority of the urban fabric of the city and reveal significant differences in their spatial patterns, as revealed from ANOVA statistics. Further, spatial indices of urban morphology like Patch, Edge index, which defines a number of built-up patches and edge density are correlated with LST patches in 16 LCZs of Bhopal. LCZ-3 is characterized by high Edge and patch densities, as compared to other LCZs and shows maximum surface temperature of 42.90C. LCZ-9 areas are characterized by a high degree of irregularity across almost all shape and form metrics, indicating sparsely dense form. However, there exists negative correlations between LST and landscape metrics of mean SHAPE and SHAPE indices are highly significant. The correlation between LST and landscape indices of development phases of Bhopal city depicted by LCZs, thus confirms the influence of spatial pattern in each LCZ on Land surface temperatures, an indicator of thermal characteristics of an area. The dense urban form pattern has higher value of LST as compared to less compact forms and irregular shapes These results highlight the role of built form regulations in determining landscape patterns that results in forming local microclimates. This research offers important insights on role of urban planning regulations in climate sensitive planning crucial for heat mitigation.

How to cite: Mistry, R. and Mehrotra, S.: Influence of Landscape patterns of Local Climate Zones on Thermal environment of Bhopal City, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-1066, https://doi.org/10.5194/icuc12-1066, 2025.

How to cite: D’Alençon, R., Vásquez, C., Salinas, C., and Da Rocha, C.: Urban Microclimates and Comfort in Santiago de Chile: Multi-scale Data Collection and Design Strategies , 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-1010, https://doi.org/10.5194/icuc12-1010, 2025.

Although the UHI has been widely investigated, UHI studies on cities in mountainous regions are limited. Previous studies have shown that mountainous cities in hot climates have unique environmental characteristics and relatively cool temperatures. Rapid urbanization followed by urban and global warming has begun to take a toll on the climatic conditions of these cities. Understanding the mechanism of the UHI in mountainous cities is challenging science due to the complex relationship between urban structure, urban landscape, varied topography and elevation.

The study aimed to monitor the formation of the Urban Heat Island (UHI) effect in Jerusalem, a city situated in a Mediterranean mountainous region near a desert frontier. The research sought to investigate the various landscape factors influencing spatial temperature variations, considering aspects such as landscape characteristics, local topo-climatic conditions, and elevation. Given the impact of complex urban topography on atmospheric conditions, the study aimed to identify systematic correlations between these factors and UHI intensity.

The methodological approach is an integrative one which includes multiple methods: Firstly, a Local Climate Zone (LCZ) classification. Secondly, meteorological observation data was collected based on official meteorological stations in and around Jerusalem. Thirdly, synoptic and atmospheric conditions are being studied using a semi-objective synoptic classification and meteorological and statistical tools.

Our findings demonstrate a strong correlation between synoptic conditions and the intensity of the urban heat island (UHI) in the Jerusalem mountains, governed by complex topographic influences and localized meteorological processes. During stable summer nights, UHI intensity can reach up to 6°C due to thermal inversions but may also be negligible, in accordance with the Israeli summer paradox. Unlike typical UHI dynamics, our results indicate that UHI in this region is more pronounced in summer than winter.

How to cite: Goldberg, A. and Potchter, O.: The Urban Heat Island of a Mountainous Mediterranean City with a Desert Frontier; The Case of Jerusalem, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-638, https://doi.org/10.5194/icuc12-638, 2025.

The urban heat island (UHI) is a ubiquitous outcome of urbanization, that is the transformation of the natural landscape and the concentration of human activities. These properties alter the natural surface-air exchanges, raising surface and air temperatures, which affects building energy use and thermal heat stress. However, the impacts of these changes depends greatly on the background climate. There have been significant advancements in UHI studies of cities in temperate climates located in high-income countries. Studies on high-altitude, cold, and dry cities are rare.  

This paper reports on a UHI study on the semi-arid city of Tabriz (Iran), which has a cold and dry climate (Köppen type BSk) and is situated at 1,350 m above sea-level. The city is almost confined entirely by mountain chains - with a significant elevation difference of around 200 m between its eastern and western parts - which resulted in a compact urban landscape. This built area is surrounded by bare lands that exhibit different diurnal thermal characteristics compared to cities located in temperate climates. An investigation into the nighttime canopy level UHI of Tabriz was conducted using a traverse approach during summer, revelaing the pattern and timing of the urban temperature effect.

This work builds on that research and focuses on the surface UHI over the course of the year. This study consists of several steps: (1) Characterizing city structure using Local Climate Zones along with socio-economic information; (2) Seasonal assessment of the diurnal urban thermal environment using remote sensing data, and; (3) linking it to the characteristics of the urban landscape using machine learning methods. 

The outcome of the study will reveal how UHI is beneficial to high-altitude cities in cold and dry climates and the implications of mitigating UHI in summer while enhancing it during cold seasons for energy efficiency.

How to cite: Koushesh Vatan, M. A. and Mills, G.: Urban thermal effect in a high-altitude, semi-arid city: Tabriz, Iran, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-1012, https://doi.org/10.5194/icuc12-1012, 2025.

Against the backdrop of global warming and rapid urban expansion, urban residents face escalating thermal risks, characterized by intensified urban heat island effects and increased heatwave frequency. Urban expansion, driven by rapid changes in spatial patterns and land use, exacerbates the urban heat island effect through increased impervious surfaces and reduced green spaces, elevating local temperatures and adversely impacting residents' health. Analyzing the spatiotemporal patterns and thermal impacts of urban expansion is therefore essential for addressing climate change and fostering livable cities. In this study, we systematically investigate the spatiotemporal characteristics of dynamic urban expansion and thermal environment evolution using data from nearly 2,000 cities across China (1985–2022) and employs machine learning models to uncover their interaction mechanisms. First, annual 30-meter resolution land use data were used to extract urban boundary dynamics and analyze spatiotemporal patterns of expansion modes, inter-city equivalent distances, and landscape indices. Second, daily 1-kilometer resolution temperature data (1961–2022) were utilized to calculate annual heatwave indicators (e.g., frequency, intensity, and duration) using the Excess Heat Factor (EHF), enabling the assessment of urban heatwave evolution. Notably, urban reference background zones were established, and regression methods were applied to isolate the independent effects of urban expansion on heatwave indicators. Finally, we implement interpretable machine learning frameworks with SHAP analysis to quantify urbanization's contribution to thermal risk amplification. Our study addresses a critical gap in large-scale urban research, providing a scientific basis for mitigating climate change and urban thermal risks. Our findings offer robust decision-making support for urban planning, contributing to sustainable urban development goals.

How to cite: Zhang, Q. and Song, J.: The role of dynamic urban expansion in shaping thermal environments: Evidence from China's 2000 cities in past decades, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-171, https://doi.org/10.5194/icuc12-171, 2025.

Although many studies have examined the impact of urban form on surface urban heat island intensity (SUHII) based on local climate zones (LCZ), the spatial-temporal heterogeneity within and between LCZs remains underexplored. Additionally, there is a need to identify key urban form indicators influencing the thermal environment across different LCZs. To address these gaps, this study investigates the influence of urban form on the spatial heterogeneity of SUHII at a 150 m x 150 m grid scale, focusing on the relationship between the two from the LCZ perspective. Using Macau, a subtropical high-density area, as a case study, this paper calculated urban form indicators, SUHII, and LCZ based on multi-source data. It applied geographically weighted regression (GWR) and geographically and temporally weighted regression (GTWR) models to analyze the spatial-temporal non-stationarity between urban form and the urban thermal environment. Additionally, Geodetector was used to rank the interpretive strength of driving factors within each LCZ class. Results show that SUHII of LCZ 8 is the highest. Comparing three regression models (OLS, GWR, and GTWR), the GWR model demonstrates the best fit for accounting for thermal variations resulting from changes in urban form. The regression performance varies significantly among LCZ classes, particularly between compact and open types. Furthermore, the results of Geodector can serve as references for urban form optimization for cooling communities, according to different contributions of driving factors in each LCZ class. For instance, reducing building density is generally relatively effective in all types of LCZ, and increasing porosity has the most significant and typical cooling effect in LCZ 2. For open LCZs, NDVI is the key factor to improve their thermal environments. This study sheds new light on the spatio-temporal variations of the “urban form-SUHII-LCZ” linkage and provides specific planning recommendations for urban heat mitigation, especially in subtropical high-density cities.

How to cite: Zhou, M., Wang, R., and Guo, Y.: How does urban form impact surface urban heat island in subtropical high-density cities: An investigation based on local climate zone, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-978, https://doi.org/10.5194/icuc12-978, 2025.

In the last decade, Outdoor Thermal Comfort (OTC) has become increasingly significant due to changing social and environmental conditions. The key physical factors influencing OTC include air temperature, global temperature, relative humidity, and wind speed, all of which directly affect the livability of urban spaces. One of the primary morphological indicators used to assess urban thermal comfort is the Sky View Factor (SVF), which represents the openness of an area to the sky. SVF plays a critical role in natural ventilation and heat dissipation, making it a crucial parameter for evaluating OTC.

This study aims to examine OTC variations based on SVF values for different urban settlement layouts in Elazığ, a mid-sized city in eastern Türkiye. Various urban configurations in Elazığ city center will be analyzed to determine how settlement geometry affects OTC. Following a series of earthquakes from 2020 to 2023, Elazığ has undergone significant urban renewal. However, OTC has often been overlooked in reconstruction and planning efforts. Given this context, the study's objectives are:

• To define the relationship between OTC and SVF for different settlement layouts.
• To identify optimal urban layouts based on SVF values to improve OTC in new urban areas of Elazığ.

The Rayman 1.2 software will be used to calculate SVF values at selected points, while Physiological Equivalent Temperature (PET), Standard Effective Temperature (SET), and Mean Radiant Temperature (MRT) will be analyzed to assess OTC. Furthermore, Computational Fluid Dynamics (CFD) simulations will be conducted to evaluate the effects of urban morphology on wind velocity, air temperature, global temperature, and humidity, considering Elazığ’s climatic conditions.

Keywords: Sky View Factor, Outdoor Thermal Comfort, Urban Morphology, CFD

How to cite: Gulten, A. and Unal, M.: Evaluation of Outdoor Thermal Comfort Based on Sky View Factor for Different Urban Morphologies, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-1038, https://doi.org/10.5194/icuc12-1038, 2025.

How to cite: Saranko, O. and Fortelius, C.: Numerical studies on the effects of surface characteristics on urban temperatures in a changing climate, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-435, https://doi.org/10.5194/icuc12-435, 2025.

The presence of cities affects local ecosystems by changing the surface energy balance and introducing anthropogenic heat, greenhouse gases, and air pollutants into the atmosphere. Currently, over 50% of the global population resides in urban areas, which increases their exposure to risks related to extreme weather and climate change. To better forecast weather and address climate adaptation and mitigation challenges, numerical weather prediction (NWP) models are beginning to integrate urban physics. However, the absence of high-quality and comprehensive urban morphology data such as building heights and footprints is still a challenge. This study introduces a high-resolution (500 m) global database developed using open data sources to support regional and global weather and climate modeling and enhance the representation of urbanization in NWP models. WUMPOD contains following urban morphological parameters; MH (mean building height), STDH (standard deviation of building height), HGT (area weighted mean building height), LP (building plan area fraction), LB (building surface to plan area fraction), LF (frontal aspect ratio for cardinal directions of 0, 45, 90, and 135 degrees), LC (complete aspect ratio), H2W (height to width ratio), HI [0-75 m] (percentage distribution of building heights at every 5 m up to 75 m), Z0M, ZDM (Roughness length and displacement height according to Macdonald et al. (1998) for 0, 45, 90, and 135 directions), Z0S, ZDS (Roughness length and displacement height according to Grimmond and Oke (1999)), Z0R, and ZDR (Roughness length and displacement height according to Raupach (1994) for 0, 45, 90, and 135 directions) and urban fraction (from WorldCover 2021). The World Urban Morphological Parameter Open Dataset (WUMPOD) is available at https://doi.org/10.5281/zenodo.10039127. The dataset will be incorporated in the development of a global ancillary and a contribution to the UK Met Office Momentum partnership.

How to cite: Patel, P. and Roth, M.: World Urban Morphological Parameters Open Dataset (WUMPOD)for High-Resolution Weather and Climate Modeling, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-168, https://doi.org/10.5194/icuc12-168, 2025.

Modeling the climate of urban areas requires a realistic urban model. But to be able to reproduce the climate of a specific city, the urban canopy model has to take into account its particularities such as the materials that make up the city, its geographical extend or the different morphologies of the urban canyon encountered in the city. Even a perfect urban canopy model needs a good representation of the city to be realistic.

OpenStreetMap is a complete, worldwide, open and collaborative database using multiple conventional and crowd-sourced data.

To take advantage of such database, Geoclimate tool has been used to retrieve the urban morphology over the whole Europe at the block scale. In addition to building, road and vegetations fractions, Geoclimate is able to retrieve the wall density and the building height in every city.

Different metrics were used to evaluate the richness of this European database. Then the data, originally in vector format has been rasterized at a 60m resolution and formatted to be used with Town Energy Balance (TEB) urban canopy model. The benefit of using such database in numerical weather prediction model such as MESONH over a well used state-of-the art land cover database such as ECOCLIMAP-SG is presented.

How to cite: Wurtz, J., Bernard, J., Bocher, E., and Masson, V.: Urban morphology at 60m resolution over Europe using Geoclimate and OpenStreetMap, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-390, https://doi.org/10.5194/icuc12-390, 2025.

How to cite: Kalverla, P., Donnely, C., Hadjiivanov, A., Steeneveld, G.-J., Timmermans, W., Sandvik, B. E., Milosevic, D., Büyükdemircioğlu, M., and Gadde, S.: Developing software to estimate thermal properties of urban fabric from open-source street view imagery , 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-352, https://doi.org/10.5194/icuc12-352, 2025.

In this study, we constructed the global urban geometric parameter database for use in mesoscale and global climate simulations. The database has a spatial resolution of 30 arcseconds in latitude and 45 arcseconds in longitude and is designed to meet the Single layer urban canopy model (Kusaka et al., 2001) input requirements. Specifically, the database includes five building parameters (average building height, maximum building height, standard deviation of building height, plane area index, and frontal area index), along with aerodynamic parameters (zero-plane displacement, aerodynamic roughness length) calculated according to Macdonald et al. (1998) and Kanda et al. (2013).

Lack of detailed building information required to calculate urban geometric has prevented the development of extensive databases. To address this issue, this study used 3 approaches to calculate the urban morphological parameters according to the availability of building data. For areas where detailed building data including building heights are available, urban geometric parameters were calculated in straightforward manner simply by collecting these data (referred to as Level 1 product). For areas where building height information is not available, we estimate building heights by generating Normalized Digital Surface Model (nDSM) from JAXA Advanced Land Observing Satellite World-3D-30 m (ALOS AW3D30), a DSM with a spatial resolution of 30 m, referring to the neighborhood analysis proposed by Huang et al. (2020), and calculated urban geometry parameters (referred to as Level 2 product). Level 2 products are available almost all over the world. Finally, the global database was completed by using Local Climate Zones (Stewart and Oke, 2012) to supplement the slight deficiencies in the level 2 product. The details of the database will be presented in the conference.

How to cite: Kawaura, A. and Nakayoshi, M.: Database Construction of Global Urban Geometric and Aerodynamic Parameters for mesoscale to global climate simulations, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-765, https://doi.org/10.5194/icuc12-765, 2025.

The overall aims of the World Urban Database and Access Portal Tools (WUDAPT) project are:
· to acquire and make accessible coherent and consistent descriptions and information on urban form and function relevant to climate weather, and environment studies on a worldwide basis,
· to provide a portal with tools that extract relevant urban parameters and properties for models and for model applications at appropriate scales for various climate, weather, environment, and urban planning purposes.
Currently, the global database available via WUDAPT is based on Local Climate Zones (LCZs), which uses 10 categories to describe the urban landscape. Each LCZ type is linked with a range of urban canopy parameter (UCP) values that can be used to support climate modelling. However, these UCP values are imprecise and invariant from city to city. Increasingly, high-resolution global databases are becoming available that can provide city-specific details on urban morphology especially. This research uses a ‘big data’ approach to generate a detailed (<1km2) UCP dataset for global cities using information from various sources including satellites, UAVs, and census data. Due to the different data availability for global cities, this research conducts a method that can calculate UCPs based on single or multiple datasets. The paper will present these methods and evaluate the results using independent sources. The urban data generated will represent an enhancement of the existing WUDAPT data.

How to cite: Li, Z. and Mills, G.: Generating Urban Canopy Paramater for Global Cities Using a Data-Driven Approach, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-534, https://doi.org/10.5194/icuc12-534, 2025.

Addressing high-temperature exposure in cities requires understanding multiple environmental dimensions, with urban morphology playing a central role. Urban morphology—which include building density, height, and arrangement—significantly influences microclimatic conditions and opportunities for adaptation. A widely used framework for studying these relationships is the Local Climate Zones (LCZ), which provides a solid theoretical foundation for understanding urban climate variations. However, LCZ categories are often idealized and may not accurately reflect the complexity of real-world environments, particularly when attempting to describe both morphological and thermal properties simultaneously.

Although urban form and thermal behavior are inherently interrelated, similar urban forms can exhibit different thermal responses depending on factors like vegetation cover, impervious surfaces, and building materials. To better represent real-world variability, separating morphological classifications from thermal characteristics allows for an analysis that accounts for these differences.

To address these challenges, we develope an approach that generates empirically derived urban morhophological types while maintaining connections to LCZ categories. Our tool systematically classifies urban morphological types for fine-grained, nationwide assessments, enabling consistent comparisons across diverse Dutch urban residential areas. This approach uses readily available geospatial data and applies unsupervised machine learning techniques to identify urban morphological typologies. By standardizing the classification process into 100 x 100 m grid cells from Statistics Netherlands, our method provides a consistent spatial and temporal framework that transcends changing administrative boundaries.

Our approach helps streamline vulnerability analysis by facilitating the intersection of multiple environmental and social dimensions. We demonstrate the tool's utility through an explorative analysis that identifies which socio-economic groups reside in neighborhoods with high heat exposure, considering both morphological types and additional factors influencing heat exposure. This tool provides urban planners and researchers with an empirically-grounded framework for identifying priority areas in existing settlements for scalable adaptation interventions across different urban contexts.

How to cite: M. Habib, M., van Esch, M., J. Timmermans, W., and van Ham, M.: Empirically-Derived Urban Morphological Typologies for Heat Vulnerability Assessment, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-258, https://doi.org/10.5194/icuc12-258, 2025.

The challenge of transferring scientific knowledge on urban climate to urban planning and design practices is persistent. Even though the Local Climate Zone (LCZ) classification tries to provide useful information to urban planning and design communities, it is more focused on a scale at which design decisions are seldom made. Approaches helpful to architects, landscape architects and urban designers need a finer spatial scale classification. This led to the exploration of Microclimatic Zone Classification (MCZ), derived based on urban parameters such as building façade materials, surface materials and trees surrounding a person. This research aims to establish a nuanced empirical relationship between the human-scale urban parameters, street orientation, sky view factor, etc, and objective thermal comfort variables, such as Air Temperature (AT), Relative Humidity (RH), Mean Radiant Temperature (MRT) and Wind Speed (WS). The approach is demonstrated in a test case in Glasgow, Scotland, using a portable non-motorised weather station (developed for this research), on a ‘Stop-and-Go’ method to measure the above variables at 38 locations in Central Glasgow’s residential and commercial neighbourhoods. These 38 locations represent the full range of available combinations of human-scale urban parameters within the case study area, making each one uniquely distinct, and the observations were carried out for a year to capture the seasonal dynamics classified per atmospheric stability class for the observation days. A regression technique using a Machine learning algorithm and the SHAP (SHapley Additive exPlanations) analysis was performed to understand the influence of various human-scale urban parameters on the objective thermal comfort variables, especially MRT (calculated using AT, WS and globe temperature). Overall, this research helps to understand the influence of urban parameters surrounding a person by ranking them from the least to the most influential in terms of their impact on thermal comfort.

How to cite: Sethupatu Bala, R., Sadeghineko, F., Emmanuel, R., Hosseinzadeh, S., and Thomson, C.: A Contribution to Microclimatic Zone Classification (MCZ), 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-96, https://doi.org/10.5194/icuc12-96, 2025.

Deciphering the complex relationships between urban form and canopy-layer air temperature has the potential to guide the parameterization of urban weather and climate models at the neighborhood scale. Many neighbourhood-scale urban morphometric properties easily extractable from OpenStreetMap and digital surface models could provide a proxy for the complex physical processes controlling canopy-layer air temperatures. Our aim is to understand how urban form at horizontal scales between 10 m and 1 km both responds to and influences pedestrian-level conditions as a first step to improving local-scale urban weather/climate modelling.

We investigate buildings-street metrics and canopy-layer air temperature variability within a city, using one year of data from 41 weather stations sited 3 m above ground in Freiburg, Germany. We explore measures of size, shape, spatial distribution and connectivity of 2- and 3-dimensional urban features at different spatial radii around the stations and how they correlate with temperature at different times of the day and year. We characterise the area with 100+ morphometric parameters, computed for and aggregated to multiple spatial scales. Some parameters are highly correlated throughout the city, many can be categorised as measures of properties, such as building density and neighbourhood heterogeneity.

For 20 heat-island nights (urban-rural temperature difference > 4 K), metrics with high values at the historic center, such as building area and compactness, are strongly correlated to nighttime canopy-layer air temperature at large radii (> 250 m). At medium radii (100 m – 300 m), metrics linked to the urban canyon such as height-width ratios strongly correlate. At small radii (< 100 m), correlations show low confidence as parameter aggregations are highly sensitive to individual building/street polygons. At this scale, metrics linked to the largest nearby building (e.g., maximum height/volume) show the most potential. Daytime correlations are weaker and more variable across temporal and spatial scales.

How to cite: Winkler, L., Fleischmann, M., Grimmond, S., Plein, M., and Christen, A.: Urban morphometric properties and their relationship to intra-urban air temperature across temporal and spatial scales, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-675, https://doi.org/10.5194/icuc12-675, 2025.

The Surface Urban Energy and Water Balance Scheme (SUEWS) is a widely used model in urban climate modelling, addressing numerous urban climatic challenges. Due to the complexity and wide range of physical processes being modelled, properly setting up the model for a specific site can be difficult. A user may have extensive knowledge of building energy but limited understanding of phenology, leading to the use of vegetation parameters that are not suited for the modelled domain.
Urban areas are heterogeneous and complex environments characterised by high variability in geometry, land use, surface materials, vegetation, and anthropogenic activity. Many NWP models utilise a grid-based approach to model energy fluxes, even though grids do not necessarily reflect the actual structure of cities. Within these grids, there is significant variability in building height, age, function, form, and materials, making proper parameterisation challenging.

To make it easier for users to choose relevant parameters, the new SUEWS property database has been developed. This database provides evidence-based parameter entries for different geographical contexts. Located within Urban Multi-scale Environmental Predictor (UMEP) toolbox in QGIS, it allows users to investigate and add parameters. A new SUEWS prepare QGIS plugin has also been developed, utilising urban typologies that represent certain properties for specific urban neighbourhoods. These typologies enable the swift calculation of urban characteristics and allow for the aggregation of parameters within SUEWS grids. Users can easily create new typologies suited to their needs.

To make the database more comprehensive, a call is being made to SUEWS users in the urban climate community to help update and fill the database with parameters from different parts of the world, building and vegetation types, traffic profiles, etc. By sharing our knowledge and parameters, we can improve SUEWS modelling for all users.

How to cite: Bäcklin, O., Lindberg, F., Sun, T., Grimmond, S., Ward, H., Järvi, L., Hertwig, D., Dou, J., Xie, X., and Liu, Y.: Development and application of an urban typology database and QGIS plugin for the SUEWS model, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-734, https://doi.org/10.5194/icuc12-734, 2025.

Urban Multi-scale Environmental Predictor (UMEP) is a climate service tool focused on urban climate simulations, using meteorological, surface, and land cover data to model a variety of climate indicators. Among these, Mean Radiant Temperature (MRT) can be computed for outdoor thermal comfort analyses, by using the Solar and LongWave Environmental Irradiance Geometry (SOLWEIG) model. A critical input for SOLWEIG is a set of Sky View Factor (SVF) maps, which quantify the fraction of visible sky at each point of the urban environment under study. However, generating these SVF maps from high-resolution digital surface models is computationally expensive and represents a significant limitation in the use of UMEP for large-scale urban studies.

Thus, this study addresses the above limitation by introducing a GPU-accelerated workflow for SVF calculation, leveraging the powerful nature of NVIDIA GPUs and PyCUDA to enable parallelized ray tracing. The proposed method incorporates anisotropic SVF calculations and accounts for vegetation canopies, which are a critical factor in accurate calculations of urban climate parameters. By replacing the CPU-based SVF calculations currently integrated within UMEP, the proposed GPU-based workflow achieves a 99% reduction in processing time while maintaining accuracy and compatibility with SOLWEIG requirements.

The proposed method was applied in the Rotterdam case study, demonstrating its usability within the UMEP climate service tool. The reduction in computational time significantly accelerates pre-processing for MRT calculations, enabling the modelling of city-large areas at a 1-meter resolution. This advancement represents a step forward in optimizing urban climate modelling workflows, enhancing their scalability and usability for researchers and practitioners.

How to cite: Van der Waal, M. and Maiullari, D.: Accelerating the UMEP workflow by introducing GPU-computed continuous Sky View Factor maps, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-179, https://doi.org/10.5194/icuc12-179, 2025.