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- An urban energy balance-guided machine learning approach for synthetic nocturnal surface Urban Heat Island prediction: a heatwave event in NaplesPublication . Oliveira, Ana; Lopes, António; Niza, Samuel; Soares, AmílcarSouthern European functional urban areas (FUAs) are increasingly subject to heatwave (HW) events, calling for anticipated climate adaptation measures. In the urban context, such adaptation strategies require a thorough understanding of the built-up response to the incoming solar radiation, i.e., the urban energy balance cycle and its implications for the Urban Heat Island (UHI) effect. Despite readily available, diurnal Land Surface Temperature (LST) data does not provide a meaningful picture of the UHI, in these midlatitudes FUAs. On the contrary, the mid-morning satellite overpass is characterized by the absence of a significant surface UHI (SUHI) signal, corresponding to the period of the day when the urban-rural air temperature difference is typically negative. Conversely, nocturnal high-resolution LST data is rarely available. In this study, an energy balance-based machine learning approach is explored, considering the Local Climate Zones (LCZ), to describe the daily cycle of the heat flux components and predict the nocturnal SUHI, during an HW event. While the urban and rural spatial outlines are not visible in the diurnal thermal image, they become apparent in the latent and storage heat flux maps – built-up infrastructures uptake heat during the day which is released back into the atmosphere, during the night, whereas vegetation land surfaces loose diurnal heat through evapotranspiration. For the LST prediction model, a random forest (RF) approach is implemented. RF results show that the model accurately predicts the LST, ensuring mean square errors inferior to 0.1 K. Both the latent and storage heat flux components, together with LCZ classification, are the most important explanatory variables for the nocturnal LST prediction, supporting the adoption of the energy balance approach. In future research, other locations and time-series data shall be trained and tested, providing an efficient local urban climate monitoring tool, where in-situ air temperature observations are not available.
- Surface radiation balance of urban materials and their impact on air temperature of an urban canyon in Lisbon, PortugalPublication . Matias, Márcia; Lopes, AntónioUrban climate results from the modifications caused by the characteristics of cities, which modifies the regional climatic conditions of a city. When urban areas are warmer than the surrounding areas, the urban heat island (UHI) phenomenon occurs. Being a major phenomenon and a global topic of interest for all affected cities, there are already numerous studies that address this subject. However, most studies are only focused on the macro and mesoscales. This study looks at the micrometeorological scale in a neighborhood of Lisbon (Telheiras). Having as a main objective to evaluate how the radiation balance of urban materials influences air temperature in an urban canyon, thermal images of different urban materials were obtained using infrared thermography, a technique that allowed understanding how the temperatures registered in the facades and other urban surfaces can affect the air temperature of the urban canyon. The components of the radiation budget were obtained by using a pyranometer and a pyrgeometer. Moreover, a microclimatic network to monitor air temperature and relative humidity was installed in the study area. The results show that, when the streets are less exposed to the prevailing wind direction in Lisbon (north and northwest), air temperatures are slightly higher than those found in opposite conditions. Both the temperature and the radiative balance of the facades and other surfaces (asphalt, light Portuguese sidewalk, and tile floor) respond directly to incident solar radiation. As expected, it was found that south facades have the highest temperatures of the four exposures under study (>4 ◦C when compared to the opposite facade), and the highest radiative balance was always registered on asphalt when compared to the sidewalk (at 9:00 a.m. + 30 W·m−2 , at 1:00 p.m. + 149 W·m−2 , and at 7:00 p.m. + 66 W·m−2 ).
- LCZ4r package R for local climate zones and urban heat islandsPublication . Anjos, Max; Medeiros, Dayvid; Castelhano, Francisco; Meier, Fred; Silva, Tiago; Correia, Ezequiel; Lopes, AntónioThe LCZ4r is a novel toolkit designed to streamline Local Climate Zones (LCZ) classification and Urban Heat Island (UHI) analysis. Built on the open-source R statistical programming platform, the LCZ4r package aims to improve the usability of the LCZ framework for climate and environment researchers. The suite of LCZ4r functions is categorized into general and local functions (https://bymaxanjos.githu b.io/LCZ4r/index.html). General functions enable users to quickly extract LCZ maps for any landmass of the world at different scales, without requiring extensive GIS expertise. They also generate a series of urban canopy parameter maps, such as impervious fractions, albedo, and sky view factor, and calculate LCZ-related area fractions. Local functions require measurement data to perform advanced geostatistical analysis, including time series, thermal anomalies, air temperature interpolation, and UHI intensity. By integrating LCZ data with interpolation techniques, LCZ4r enhances air temperature modeling, capturing well-defined thermal patterns, such as vegetation-dominated areas, that traditional methods often overlook. The openly available and reproducible R-based scripts ensure consistent results and broad applicability, making LCZ4r a valuable tool for researchers studying the relationship between land use-cover and urban climates.
- Beyond usual geographical scales of analysis: implications for healthcare management and urban planningPublication . Morais, Liliane; Lopes, António; Rocha, Jorge; Nogueira, Paulo JorgeIntroduction: In the context of climate emergency, advances in geographic information systems, geocoding, and geomedicine allow us to go beyond the conventional usual scales and be aligned with people’s needs, improving knowledge and accuracy of the spatial pattern of health outcomes. This study shows that the geographical scale of analysis affects the interpretation of health outcomes. Methods: All mortality that occurred in Portugal in 2014–2017 was geocoded. From 435,291 addresses, 412,608 were geocoded with success. As an example, we use the spatial patterns of the elderly’s heat-related cardiorespiratory mortality. Results: It is shown: (i) it is possible to have high quality and accuracy of spatial data used in health outcomes analysis; (ii) how geographic scales reveal different degrees of detail in health outcomes analysis; (iii) the neighbourhood scale revealed different patterns of cardiorespiratory mortality from the usually available scale (parish). Discussion: Our findings suggest the relevance of geocoding health outcomes with a finer scale in tackling the challenges of the healthcare sector, and in support of planning decision-making, closely matching citizens’ needs. Without running the risk of losing potentially major prospects, better healthcare management is achievable, with optimal resource allocation, and improved detailed and informed policymaking, allowing enhanced climate health equity in cities promotion.
- An urban energy balance-guided machine learning approach for synthetic nocturnal surface Urban Heat Island prediction: a heatwave event in NaplesPublication . Oliveira, Ana; Lopes, António; Niza, Samuel; Soares, AmílcarSouthern European functional urban areas (FUAs) are increasingly subject to heatwave (HW) events, calling for anticipated climate adaptation measures. In the urban context, such adaptation strategies require a thorough understanding of the built-up response to the incoming solar radiation, i.e., the urban energy balance cycle and its implications for the Urban Heat Island (UHI) effect. Despite readily available, diurnal Land Surface Temperature (LST) data does not provide a meaningful picture of the UHI, in these midlatitudes FUAs. On the contrary, the mid-morning satellite overpass is characterized by the absence of a significant surface UHI (SUHI) signal, corresponding to the period of the day when the urban-rural air temperature difference is typically negative. Conversely, nocturnal high-resolution LST data is rarely available. In this study, an energy balance-based machine learning approach is explored, considering the Local Climate Zones (LCZ), to describe the daily cycle of the heat flux components and predict the nocturnal SUHI, during an HW event. While the urban and rural spatial outlines are not visible in the diurnal thermal image, they become apparent in the latent and storage heat flux maps – built-up infrastructures uptake heat during the day which is released back into the atmosphere, during the night, whereas vegetation land surfaces loose diurnal heat through evapotranspiration. For the LST prediction model, a random forest (RF) approach is implemented. RF results show that the model accurately predicts the LST, ensuring mean square errors inferior to 0.1 K. Both the latent and storage heat flux components, together with LCZ classification, are the most important explanatory variables for the nocturnal LST prediction, supporting the adoption of the energy balance approach. In future research, other locations and time-series data shall be trained and tested, providing an efficient local urban climate monitoring tool, where in-situ air temperature observations are not available.
- Local climate zones in five southern European cities: an improved GIS-based classification method based on Copernicus dataPublication . Oliveira, Ana; Lopes, António; Niza, SamuelWhile climate change projections for the Mediterranean region indicate an increased exposure to heatwaves (HW), such prospects are particularly challenging in urban areas, where thermal stress can be exacerbated by the Urban Heat Island (UHI) effect. In that regard, understanding spatial patterns of thermal performance is of the utmost importance, in order to address corresponding adaptation measures. Local Climate Zones (LCZ) have become the standard typification of Land Cover/Land Use classes, according to their climatic response. However, the corresponding satellite- based classification method from the World Urban Database and Access Portal Tools (WUDAPT) presents accuracy issues when applied to European cities. Several studies have provided alternative LCZ methodologies, but these usually require data which is not often readily available (e.g. high-resolution digital surface models), therefore rendereing them hard to replicate. This study addresses this issue by developing an alternative geographic information system (GIS)-based method, and the corresponding toolbox, to translate Copernicus datasets into LCZ maps: Urban Atlas and Corine Land Cover shapefiles are used as the baseline dataset for the reclassification. The method was proven to be accurate in the five cities used in the case study - Athens, Barcelona, Lisbon, Marseille, and Naples - 81% overall accuracy, and 0.79 Kappa coefficient, on average. Results reveal the presence of a diurnal surface UHI, with lower land surface temperatures (LST) found in tree covered areas. However, similar LST found in the other LCZ classes (e.g. between compact and sparsely built-up areas) indicates that diurnal patterns of the urban energy balance components must be considered to better characterise the UHI of these cities.
- Heat stress mitigation by exploring UTCI hotspots and enhancing thermal comfort through street treesPublication . Silva, Tiago; Matias, Márcia; Girotti, Carolina; Vasconcelos, João; Lopes, AntónioHeat stress mitigation actions must be carefully planned in order to achieve efective outcomes. By integrating urban planning guidelines with urban climate knowledge, substantial benefts can be achieved for the community. In Lisbon, the study area, urban planning guidelines are strict in relation to the tree species which should be used for planting. This study examined these species environmental contributions to the community, especially in regard to heat stress mitigation in two urban canyons previously found as UTCI hotspots. For this, microclimatic Envi-met simulations were run which allowed recalculation of the UTCI hotspot analysis and to assess individual species contribution to possible mitigation eforts. Results demonstrated the ability of these trees to lower air temperature and the Universal Thermal Climate Index (UTCI). By reducing UTCI temperatures between 3.19 °C and 6.27 °C on a hot summer’s day, these trees were also able to transform an identifed UTCI hotspot into a coldspot. From the studied species, Pyrus calleryana was found to be the most efective species for mitigating thermal stress, although all three species performed well. Regarding community services, according to the iTree tool, Cercis siliquastrum had the greatest overall impact. These results give to the municipal urban planning which tree species should be prioritized in terms of climate action, as well as a methodological framework to assess at local scale which areas should be intervened.
- Air pollution and emergency hospital admissions: evidences from Lisbon Metropolitan Area, PortugalPublication . Franco, Pedro; Gordo, Cristina; Marques Da Costa, Eduarda; Lopes, AntónioThe relevance of air pollution in the public health agenda has recently been reinforced—it is known that exposure to it has negative effects in the health of individuals, especially in big cities and metropolitan areas. In this article we observed the evolution of air pollutants (CO, NO, NO2, O3, PM10) emissions and we confront them with health vulnerabilities related to respiratory and circulatory diseases (all circulatory diseases, cardiac diseases, cerebrovascular disease, ischemic heart disease, all respiratory diseases, chronic lower respiratory diseases, acute upper respiratory infections). The study is supported in two databases, one of air pollutants and the other of emergency hospital admissions, in the 2005–2015 period, applied to the Lisbon Metropolitan Area. The analysis was conducted through Ordinary Least Squares (OLS) regression, while also using semi-elasticity to quantify associations. Results showed positive associations between air pollutants and admissions, tendentially higher in respiratory diseases, with CO and O3 having the highest number of associations, and the senior age group being the most impacted. We concluded that O3 is a good predictor for the under-15 age group and PM10 for the over-64 age group; also, there seems to exist a distinction between the urban city core and its suburban areas in air pollution and its relation to emergency hospital admissions.
- Thermal preference and pleasantness of a students’ population in a coastal urban area during summerPublication . Silva, Tiago; Lopes, António; Vasconcelos, João; Morgado, PauloIn thermal comfort research, two main domains are identified: objective and subjective. This study focusses on the latter, examining various aspects of preference, sensation, and pleasantness. It also clearly distinguishes each concept and sets the groundwork for their standardised use in urban planning and urban climate studies. Additionally, this study emphasises the often-overlooked geographical perspective, aiming to address previous gaps in this research area. Environmental conditions were found to be the main determinants influencing pedestrians' thermal sensation, preference, and pleasure. Key factors include air temperature, solar radiation, and wind speed, which exhibit strong correlations with pleasure responses. Additionally, urban density, clothing type and colour, shading, sex, and weather type significantly impact thermal sensation and reported pleasantness. It was observed that people who overdressed for the season, wore dark or warmer clothes, experienced air temperature and solar radiation more intensely. Similarly, those in high-density urban areas, without shade, or when weak continental wind conditions were observed, reported stronger thermal sensations. Women generally sensed air temperature and solar radiation as more intense compared to men. These factors influence thermal pleasantness, varying in importance, spatial distribution, and statistical relationship. Higher wind speeds, particularly from an Atlantic direction, were found to enhance thermal pleasantness by balancing conditions and reducing thermal sensation votes for air temperature and solar radiation. Green areas also increased thermal pleasantness by lowering air temperature and solar radiation sensations and promoting a sense of happiness among pedestrians.
- Comparative study of microclimatic variables in industrial and residential areas of a tropical city using computational simulation and multivariate analysisPublication . Arruda, Angela Maria de; Lopes, António; Masiero, ÉricoThe efects of urban heat islands (UHIs) have intensifed with increasing urbanization and industrialization of natural environments. This study aims to identify the formation of UHIs in an industrial district by analyzing possible correlations between the variables that infuence the urban microclimate. Data were collected in situ over 15 days, focusing on air temperature and relative humidity in both an industrial neighborhood (DI) and a central residential area (R) in Uberlândia, MG. To estimate UHI intensity, data from a meteorological station at the airport were used. Air temperature (Tar) was measured, and land surface temperature (LST) was simulated. The peak UHI intensity occurred at 9 p.m, reaching 1.5 °C in R and 5 °C in DI. In the R area, wind speed (WS) and sky view factor (SVF) (0.505), as well as relative humidity (RH) and turbulent kinetic energy (TKE) (0.603), showed strong positive correlations. Conversely, Tar and RH were strongly negatively correlated (-0.981). In the industrial area (DI), LST and Tar (0.603), SVF and WS (0.704), WS and wind direction (WD) (0.643), WD and SVF (0.694), and again RH and TKE (0.705) exhibited strong correlations, highlighting the signifcance of wind at this location, particularly when supported by the orientation of the main streets. Given the recorded UHI intensity and the most impactful variables detected for DI, urban planning that emphasizes improved distribution and layout of streets and avenues positioning them to favor the predominant WD, maintaining WS, and consequently enhancing heat dissipation along with increased aforestation and judicious application of surface materials, could help cool the area.