ANNUAL CONGRESS 2025

Analyzing Spatial Pattern of Relatively Cooler Areas to Mitigate Urban Heat Islands in İzmir

Not scheduled

20m

Yildiz Technical University, Istanbul

Oral Track 05 | ENVIRONMENT AND CLIMATE

Speaker

Dr Yasemin Şentürk (1. yazar)

Description

Urban heat islands (UHIs) are a significant environmental challenge in modern urban areas, characterized by elevated temperatures compared to rural surroundings. This phenomenon arises from factors such as reduced vegetation, increased impervious surfaces, and dense urbanization (Leconte et al., 2015). Addressing UHIs is critical for enhancing urban livability, public health, and environmental sustainability. The spatial distribution of land surface temperatures (LST) in urban areas shows heterogeneity (Li et al., 2017), with clusters of relatively cooler areas (RCAs) exhibiting distinct spatial patterns. This study investigates the potential of RCAs as a strategy to mitigate UHI effects, hypothesizing that RCAs are more frequent in areas with higher green density or urban gaps and diminish in regions with low permeability and high construction density. Expanding RCAs could mitigate UHI risks and improve urban climates.
In analyzing the role of urban morphology in UHI dynamics, previous research highlights the importance of urban morphology in regulating UHI intensity. Factors such as building density, urban geometry, and permeability significantly influence airflow and heat distribution. High porosity in urban structures enhances airflow, thereby reducing UHI intensity (Park et al., 2017). Conversely, continuous building blocks hinder the cooling effects of parks (Silva et al., 2018). Additionally, air ventilation, sun exposure, and urban geometry play critical roles in shaping local climatic conditions (Peng et al., 2017). However, these studies generally focus on the direct relationship between morphological parameters and temperature. Taking a different spatial analysis approach, this study aims to analyze the urban morphological characteristics of RCAs in İzmir, Turkey.
Located in the Aegean region, İzmir is Turkey’s third-largest city. With a Mediterranean climate, İzmir has experienced a rise in extreme heat days since 1975, reflecting broader regional climate trends. In this context, understanding the relationship between urban morphology and RCAs is vital for informed urban planning and UHI mitigation. To measure cooling intensity, LST data were generated using Landsat OLI 8’s thermal band 10 in ArcGIS Pro, while polygon data of buildings were used to calculate urban morphological parameters. Spatial autocorrelation was analyzed using Anselin Moran’s I to identify clusters of low-temperature areas (Guo et al., 2019). Linear and spatial regression models were employed to measure the relationship between morphological parameters—such as building height, average distance between buildings, surface area ratios, and permeability—and RCA sizes. Initial findings reveal that RCA magnitudes decrease in areas with low permeability and high construction density. In İzmir, cooler areas were observed near the seaside, although this effect diminished in adjacent urban interiors, such as Karşıyaka and Bayraklı. Some urbanized districts, including Evka3, Mavişehir, and Manavkuyu, also showed lower LST values, suggesting that specific urban morphologies contribute to the formation and maintenance of RCAs (Şentürk, 2024). The study's findings of the spatial regression model revealed that the average building height, average building size, average building surface area, ground built-up ratio, total built-up ratio, and inter-building distance parameters significantly contribute to explaining the size of urban cold areas in the Izmir urban area. Consistent with findings in the literature, it was observed that split-layout building designs with more permeable structures positively influenced the spread of the cooling effect. In contrast, the magnitude of the RCA decreased as surface areas increased and urban voids diminished.
To sum up, this research underscores the significant interplay between urban morphology and thermal dynamics. By identifying and preserving RCAs, urban planners can enhance strategies for mitigating UHIs, improving spatial planning, and promoting sustainable urban design. These findings provide valuable insights into how morphological factors influence LST patterns, supporting the development of climate-resilient cities.

References

Guo, G., Wu, Z. & Chen, Y. (2019). Complex mechanisms linking land surface temperature to greenspace spatial patterns: Evidence from four southeastern Chinese cities. Science of Total Environment, 674, 77-87.
Leconte, P., Bouyer, J. Claverie., R. & Petrissans, M. (2015). Using Local Climate Zone scheme for UHI assessment: Evaluation of the method using mobile measurements. Building and Environment, 83, 39-49
Li, W., Cao, Q., Lang, K., Wu, (2017). Linking potential heat source and sink to urban heat island: Heterogeneous effects of landscape pattern on land surface temperature. Science of the Total Environment, 586, 457–465.
Park, C., Ha, J & Lee, S. (2017). Association between Three-Dimensional Built Environment and Urban Air Temperature: Seasonal and Temporal Differences. Sustainability, 9, 1338.
Silva, I., Santos, R., Lopes, A. & Araujo, V. (2018). Morphological Indices as Urban Planning Tools in Northeastern Brazil. Sustainability, 10, 4358
Peng, F., Wong, M. S., Ho, H. C., Nichol, J. & Chan, P.W. (2017). Reconstruction of historical datasets for analyzing spatiotemporal influence of built environment on urban microclimates across a compact city. Building and Environment, 123, 649-660.
Şentürk, Y. (2024). Investigating cooling effect of green spaces in urban areas within the smart cities frameworks.(PhD Thesis), Dokuz Eylül Üniversitesi, İzmir.