Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography

This study investigates the spatiotemporal dynamics of land surface temperature (LST) across five distinct land use/land cover (LULC) classes through high-resolution unmanned aerial vehicle (UAV) thermal remote sensing. Thermal orthomosaics were systematically captured at four diurnal periods (morni...

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Main Authors: Nizar Polat, Abdulkadir Memduhoğlu
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/7/3448
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author Nizar Polat
Abdulkadir Memduhoğlu
author_facet Nizar Polat
Abdulkadir Memduhoğlu
author_sort Nizar Polat
collection DOAJ
description This study investigates the spatiotemporal dynamics of land surface temperature (LST) across five distinct land use/land cover (LULC) classes through high-resolution unmanned aerial vehicle (UAV) thermal remote sensing. Thermal orthomosaics were systematically captured at four diurnal periods (morning, afternoon, evening, and midnight) over an urban university campus environment. Using stratified random sampling in each class with spatial controls to minimize autocorrelation, we quantified thermal signatures across bare soil, buildings, grassland, paved roads, and water bodies. Statistical analyses incorporating outlier management via the Interquartile Range (IQR) method, spatial autocorrelation assessment using Moran’s <i>I</i>, correlation testing, and Geographically Weighted Regression (GWR) revealed substantial thermal variability across LULC classes, with temperature differentials of up to 17.7 °C between grassland (20.57 ± 5.13 °C) and water bodies (7.10 ± 1.25 °C) during afternoon periods. The Moran’s <i>I</i> analysis indicated notable spatial dependence in land surface temperature, justifying the use of GWR to model these spatial patterns. Impervious surfaces demonstrated pronounced heat retention capabilities, with paved roads maintaining elevated temperatures into evening (13.18 ± 3.49 °C) and midnight (2.25 ± 1.51 °C) periods despite ambient cooling. Water bodies exhibited exceptional thermal stability (SD range: 0.79–2.85 °C across all periods), while grasslands showed efficient nocturnal cooling (ΔT = 23.02 °C from afternoon to midnight). GWR models identified spatially heterogeneous relationships between LST patterns and LULC distribution, with water bodies exerting the strongest localized cooling influence (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>R</mi><mn>2</mn></msup></semantics></math></inline-formula>≈ 0.62–0.68 during morning/evening periods). The findings demonstrate that surface material properties significantly modulate diurnal heat flux dynamics, with human-made surfaces contributing to prolonged thermal loading. This research advances urban microclimate monitoring methodologies by integrating high-resolution UAV thermal imagery with robust statistical frameworks, providing empirically-grounded insights for climate-adaptive urban planning and heat mitigation strategies. Future work should incorporate multi-seasonal observations, in situ validation instrumentation, and integration with human thermal comfort indices.
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spelling doaj-art-4d28e268bda0436a8bb8aec414c25db12025-08-20T03:08:43ZengMDPI AGApplied Sciences2076-34172025-03-01157344810.3390/app15073448Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV ThermographyNizar Polat0Abdulkadir Memduhoğlu1Department of Geomatics Engineering, Faculty of Engineering, Harran University, 63100 Sanliurfa, TürkiyeDepartment of Geomatics Engineering, Faculty of Engineering, Harran University, 63100 Sanliurfa, TürkiyeThis study investigates the spatiotemporal dynamics of land surface temperature (LST) across five distinct land use/land cover (LULC) classes through high-resolution unmanned aerial vehicle (UAV) thermal remote sensing. Thermal orthomosaics were systematically captured at four diurnal periods (morning, afternoon, evening, and midnight) over an urban university campus environment. Using stratified random sampling in each class with spatial controls to minimize autocorrelation, we quantified thermal signatures across bare soil, buildings, grassland, paved roads, and water bodies. Statistical analyses incorporating outlier management via the Interquartile Range (IQR) method, spatial autocorrelation assessment using Moran’s <i>I</i>, correlation testing, and Geographically Weighted Regression (GWR) revealed substantial thermal variability across LULC classes, with temperature differentials of up to 17.7 °C between grassland (20.57 ± 5.13 °C) and water bodies (7.10 ± 1.25 °C) during afternoon periods. The Moran’s <i>I</i> analysis indicated notable spatial dependence in land surface temperature, justifying the use of GWR to model these spatial patterns. Impervious surfaces demonstrated pronounced heat retention capabilities, with paved roads maintaining elevated temperatures into evening (13.18 ± 3.49 °C) and midnight (2.25 ± 1.51 °C) periods despite ambient cooling. Water bodies exhibited exceptional thermal stability (SD range: 0.79–2.85 °C across all periods), while grasslands showed efficient nocturnal cooling (ΔT = 23.02 °C from afternoon to midnight). GWR models identified spatially heterogeneous relationships between LST patterns and LULC distribution, with water bodies exerting the strongest localized cooling influence (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>R</mi><mn>2</mn></msup></semantics></math></inline-formula>≈ 0.62–0.68 during morning/evening periods). The findings demonstrate that surface material properties significantly modulate diurnal heat flux dynamics, with human-made surfaces contributing to prolonged thermal loading. This research advances urban microclimate monitoring methodologies by integrating high-resolution UAV thermal imagery with robust statistical frameworks, providing empirically-grounded insights for climate-adaptive urban planning and heat mitigation strategies. Future work should incorporate multi-seasonal observations, in situ validation instrumentation, and integration with human thermal comfort indices.https://www.mdpi.com/2076-3417/15/7/3448unmanned aerial vehiclethermal infrared imagingland surface temperatureland use/land cover classificationdiurnal thermal variabilityurban heat island
spellingShingle Nizar Polat
Abdulkadir Memduhoğlu
Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography
Applied Sciences
unmanned aerial vehicle
thermal infrared imaging
land surface temperature
land use/land cover classification
diurnal thermal variability
urban heat island
title Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography
title_full Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography
title_fullStr Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography
title_full_unstemmed Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography
title_short Assessing Spatiotemporal LST Variations in Urban Landscapes Using Diurnal UAV Thermography
title_sort assessing spatiotemporal lst variations in urban landscapes using diurnal uav thermography
topic unmanned aerial vehicle
thermal infrared imaging
land surface temperature
land use/land cover classification
diurnal thermal variability
urban heat island
url https://www.mdpi.com/2076-3417/15/7/3448
work_keys_str_mv AT nizarpolat assessingspatiotemporallstvariationsinurbanlandscapesusingdiurnaluavthermography
AT abdulkadirmemduhoglu assessingspatiotemporallstvariationsinurbanlandscapesusingdiurnaluavthermography