Urban Morphological Controls on Surface Thermal Dynamics: A Comparative Assessment of Major European Cities with a Focus on Athens, Greece

Abstract

Variations in urban form lead to the development of distinctive intra-urban surface thermal patterns. Previous assessment of the relation between urban structure and satellite-based Land Surface Temperature (LST) has generally been limited to single-city cases. Here, examining 25 European cities (June–August 2017), we estimated the statistical association between surface parameters—the impervious fraction (λimp), the building fraction (λb), and the building height (H)—and the neighborhood scale (1000 × 1000 m) LST variations, as captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Correlation analysis, multiple linear regression, and spatial regression were used. As expected, λimp had a consistent positive influence on LSTs. In contrast, the relation of LST with λb and H was generally weaker or negative in the daytime, whereas at night it shifted to a robust positive effect. In particular, daytime LSTs of densely built, high-rise European districts tended to have lower values. This was especially the case for the city of Athens, Greece, where a more focused analysis was conducted, using further surface parameters and the Local Climate Zone (LCZ) scheme. For the urban core of the city, the canyon aspect ratio H/W had a statistically significant (p <0.01) negative relationship with LST by day (Spearman’s rho = −0.68) and positive during nighttime (rho = 0.45). The prevailing intra-urban surface thermal variability in Athens was well reproduced by a 5-day numerical experiment using the meteorological Weather Research and Forecasting Model (WRF) model and a modified urban parameterization scheme. Although the simulation resulted in some systematic errors, the overall accuracy of the model was adequate, regarding the surface temperature (RMSE = 2.4 K) and the near-surface air temperature (RMSE = 1.7 K) estimations.

The planetary boundary layer physical processes, the secondary thermal baroclinic circulation and inertial oscillation contribution to diurnal variation of the Etesian winds over the Aegean Sea

“…This balance keeps almost steady until the sunset. This sort of baroclinic circulation appears frequently thanks to the development of distinctive intra-urban surface thermal patterns reported by Agathangelidis et al, (2020) in 25 European cities with Athens included, aggregating their findings to similar ones of so many Greek, and not only, scientists mentioned broadly above. Similar circulation should be tested over the open sea when a distinct gradient appears in SST, as this between North Aegean and Karpathion Seas or Antalya's gulf and Middle East coastal waters.…”

“…Since 1990, many attempts have been made by Greek scientists to explore the PBL mainly in rural and coastal places in conjunction with atmospheric pollution and the contribution of local and regional sea-land breezes. All of these papers, which appeared in the international literature deal with the PBL structure and their findings are mostly derived from experimental real observational data (Asimakopoulos et al, 1993;Soilemes et al, 1993;Asimakopoulos and Helmis, 1994;Founda et al, 1997;Helmis et al, 2002;Tombrou et al, 2007;Kostopoulos and Helmis, 2014;Helmis et al, 2015;Dandou et al, 2017;Agathangelidis et al, 2020;Mithimaki et al, 2020). The distinguished observational campaign held over the Aegean Sea (GAME) during late August and early September in 2011 (Tombrou et al, 2007;Dandou et al, 2017) provided many scientists with the necessary measurements to elaborate extensive research work relevant to Aegean sea PBL.…”

Modelo de regressão para identificação de ilha de calor

“…Por sua vez, o número de variáveis consideradas variou entre os diferentes trabalhos. Observou-se que, de um modo geral, ocorreu a avaliação entre duas variáveis dependentes (Li et al, 2017;Isa;Wan Mohd;Salleh, 2017;Agathangelidis;Cartalis;Santamouris, 2020;NGUYEN, 2020) e 36 (Alonso;Renard, 2020). A Figura 10 apresenta a distribuição do número de variáveis na amostra aderente.…”

CitySurfaces: City-Scale Semantic Segmentation of Sidewalk Materials

“…The lack of data creates barriers to understanding the real extent of the environmental and social impacts of using different materials and inhibits our ability to take a complex system approach to sustainability assessment (Van Dam et al, 2015). For instance, studies show a significant intra-urban variability of the urban thermal environment due to the street-level heterogeneity of paving materials (Agathangelidis et al, 2020). However, the data scarcity makes it challenging to measure this variability across different neighborhoods and consequently, impedes the development of a sustainable and resilient mitigation response plan (Akbari & Rose, 2008;Li et al, 2013;Yang et al, 2019).…”