Analysis of the urban heat island in Bragança, Portugal, using MODIS data (2003-2022)

Almeida, Cátia Rodrigues de; Alirio, João; Gonçalves, Artur; Teodoro, Ana Cláudia

http://hdl.handle.net/10198/29412

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Authors

Almeida, Cátia Rodrigues de

Alirio, João

Gonçalves, Artur

Teodoro, Ana Cláudia

Abstract(s)

Urban Heat Island (UHI) is an effect that corroborates to the increase of temperature in urban settlements when compared to the surrounding vegetated areas, especially after sunset. This research aimed to understand the Surface Urban Heat Island (SUHI), a sub-classification correlated to the UHI effect, in the city of Bragança (Portugal), at 23 points classified in different Local Climate Zone (LCZ), between 2003 and 2022, using Remote Sensing (RS) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The data were obtained at four passage times: 11am, 1pm, 10pm and 2am and analysed separately for summer and winter. Qualitative and quantitative analyses were applied, using an average of 1,337 Land Surface Temperature (LST) data, processed in the Google Earth Engine (GEE) platform. The computation of the SUHI intensity (SUHIint) for each year was obtained from the differences in LST between each of the LCZ and the average values from Rural Areas (RCD), considering both summer and winter campaigns. The boxplots showed similar medians in all LCZs at 11am and 1pm. At 10pm and 2am, only slight differences were found among the median values. The similarity in results may be associated with the low spatial resolution of the sensor and the difficulty in distinguishing between LCZs. The SUHIint was positive in most of the results (about 71%). Of the 23 points analysed, ten were not located in unique pixels, which compromised the analysis of the results in the different LCZs. This condition reinforces the need for use higher spatial resolution data to allow for a differentiation among LCZs data.

Keywords

Google Earth engine Land surface temperature Local climate zone MODIS sensor Remote sensing

URI

http://hdl.handle.net/10198/29412

Citation

Almeida, Cátia Rodrigues de; Alírio, João; Gonçalves, Artur; Teodoro, Ana Cláudia (2023). Analysis of the urban heat island in Bragança, Portugal, using MODIS data (2003-2022). In Earth Resources and Environmental Remote Sensing/GIS Applications XIV. p. 1-14. ISBN 978-1-5106-6697-9