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- 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.
- Annual summaries dataset of Heatwaves in Europe, as defined by the Excess Heat FactorPublication . Oliveira, Ana; Lopes, António; Correia, EzequielThe dataset includes six yearly time series of six Heatwave (HW) aspects/metrics (or statistical summaries) calculated from the E-OBS dataset (v19eHOM, available in https://www.ecad.eu/download/ensembles/downloadversion19.0eHOM.php) following the Excess Heat Factor (EHF) methodology implemented in the ClimPACT tool, in compliance with the guidelines established by the Expert Team on Climate Change Detection and Indices (ET-SCI). These aspects correspond to annual summaries of HW frequency, duration and intensity, considering solely the events occurring during the extended summer season (from June to September). Input Daily Maximum (TX) and Minimum (TN) near-surface air temperature data were retrieved from a European gridded dataset (E-OBS) – the ensemble homogenized version ‘19.0eHOM’, at 0.1° × 0.1° spatial resolution, covering the European region, and retrieved from the EU-FP6 project UERRA (http://www.uerra.eu) and the Copernicus Climate Change Service. The E-OBS dataset is based on station observations, provided by the European Climate Assessment & Dataset. The here-presented HW aspects/summaries outputs of the ClimPACT tool correspond to the gridded annual statistical summaries of HW – these are detected based on the positive Excess Heat Factor (EHF) days, an HW index based on the human health response to heat extremes. The summaries include: (i) annual Number of Heatwaves (HWN); (ii) annual Heatwave Days Frequency (HWF); (iii) annual Maximum Heatwave Duration (HWD); (iv) annual Mean Heatwave Magnitude (HWM); and (v) annual Maximum Heatwave Amplitude (HWA). In addition, the annual maximum Heatwave Severity (HWS) was calculated, by dividing HWA by the 85th percentile of the positive EHF days. These annual time series can be used in HW-related studies focusing on the European region, particularly those focusing on climatology, trends, and impacts on human health.
- Air pollution Dynamics: the role of meteorological factors in PM10 concentration patterns across urban areasPublication . Girotti, Carolina; Fernando Kowalski, Luiz; Silva, Tiago; Correia, Ezequiel; Shimomura, Alessandra R. Prata; Akira Kurokawa, Fernando; Lopes, AntónioAir pollution is a major health problem in urban areas, influenced by traffic and atmospheric conditions. This study investigates the relationship between meteorological factors—wind direction, wind speed, boundary layer height, and atmospheric stability conditions —street trees, and PM10 concentration in three urban canyons: Avenida da Liberdade and Estrada de Benfica in Lisbon, and Marginal Tietˆe in S˜ ao Paulo. Five years of hourly meteorological data and PM10 concentrations were analysed. Despite differences in scale and traffic volume, the results show that PM10 concentration patterns were similar in both Lisbon study areas. These areas also indi cated a significant influence of atmospheric variables such as wind speed, boundary layer height, and atmo spheric stability conditions. Tietˆe, with a higher vehicle density and different atmospheric conditions (lower wind speeds and greater atmospheric stability), presents higher PM10 peaks. Seasonal analysis revealed distinct patterns influenced by atmospheric instability, wind speed, and direction. In winter, areas with dense street tree cover had reduced PM10 levels, while those without showed higher concentrations due to increased stability. Wind direction played a crucial role, favouring the pollutant dispersal in canyons with parallel winds. The Factorial Analysis of Mixed Data method identified qualitative variables linked to the seasons, wind direction, and presence of trees. PM10 levels below the were associated with the summer and autumn period, parallel winds, and street trees, while levels above the limit were linked to winter period and areas without street trees. By integrating big data analytics with environmental monitoring, this research underscores the importance of considering the local atmospheric conditions and environmental variables in the urban air quality management. Thus, it demonstrates that the traffic volume alone does not determine PM10 concentrations; instead, the interplay of multiple factors, including meteorological conditions and urban planning, played a crucial role. This study provides valuable insights for developing effective strategies to mitigate urban air pollution and protect public health.
- Indoor thermal comfort in informal settlements: a case study of Mafalala, MaputoPublication . Correia, Ezequiel; Henriques, Cristina DelgadoThe rapid urbanization of African cities has intensified economic disparities, leading to residential segregation and inadequate housing conditions. This study examines indoor thermal comfort in the Mafalala neighborhood of Maputo, Mozambique, highlighting the severe impact of poor housing on residents’ well-being. For the first time, indoor temperature and humidity were measured and thermal comfort was assessed based on data collected from five dwellings during two campaigns in 2023. Results reveal significant thermal discomfort, particularly during the hot season. The widespread use of galvanized steel sheets for roofing and some walls exacerbates indoor temperatures, with some dwellings reaching up to 49°C during hot spells. While concrete block dwellings provide higher thermal inertia, they remain vulnerable due to poor insulation and ventilation. Using the Adaptive Comfort Model and Physiological Equivalent Temperature to assess thermal comfort and physiological stress, the analysis shows that dwellings are uncomfortable most of the time, exposing residents to moderate to extreme heat stress. Findings highlight the need for materials with higher thermal inertia, enhancing insulation, adequate ventilation, and shading solutions.
- Microclimate simulation and lichen-based validation analyzing street trees' impact on atmospheric pollutant dispersion at the urban canyon scalePublication . Girotti, Carolina; Matos, Paula; Shimomura, Alessandra R. Prata; Kurokawa, Fernando Akira; Correia, Ezequiel; Lopes, AntónioThis study investigates the impact of street trees on air pollutant concentrations, specifically NO₂ and PM10, in urban environments using computational fluid dynamics (CFD) simulations with ENVI-met software. The study explores how different levels of tree cover influence the dispersion of atmospheric pollutants, focusing on three scenarios: current tree cover, complete removal of street trees, and a 50 % reduction in tree cover. Avenida da Liberdade in Lisbon, known for its high tree density, serves as the study site. To ensure the accuracy of the simulations, the method was validated using air quality data from a local monitoring station, supplemented by an analysis of lichen diversity on 80 trees, a common biomonitor for pollution. The results indicate that both NO₂ and PM10 concentrations are higher under tree canopies, with the greatest increase observed on the windward side of the avenue. Specifically, PM10 levels rose by up to 2.97 %, and NO₂ by up to 25.84 % in the scenario with the highest tree cover. Moreover, the study highlights that street trees have a more significant effect on NO₂ concentrations compared to PM10. The findings suggest that, in this specific case—where there is a high density of trees and low wind speed— reducing tree coverage and improve permeability to the wind, could improve pollution dispersion. This study provides key findings into the complex role of urban trees in air quality and offers a foundation for future research into the modelling of additional pollutants, such as PM2.5 and ozone, to gain a more comprehensive understanding of their impacts on urban air quality.
- A Avaliação de Riscos Climáticos nos Planos Municipais de Emergência em Portugal: métodos e experiênciaPublication . Lopes, António; Fragoso, Marcelo; Correia, EzequielProcede-se a uma breve reflexão sobre as metodologias de avaliação da perigosidade, suscetibilidade e risco associados a diferentes tipos de condições atmosféricas adversas, no contexto do planeamento de emergência à escala municipal. A colaboração dos autores em diversos planos municipais de emergência desenvolvidos entre 2011 e 2014 suscitou a realização de diferentes abordagens metodológicas, sendo aqui sucintamente apresentados alguns exemplos respeitantes a perigos como o nevoeiro, as tempestades ou as ondas de calor, avaliados em diferentes territórios municipais como o Funchal, Oeiras e Setúbal. É destacada a importância deste tipo de avaliação dever ser suportado por um conhecimento das características topoclimáticas dominantes nas áreas em estudo e apontam-se algumas possíveis soluções para algumas dificuldades que são comuns neste tipo de planos, nomeadamente, no que diz respeito à informação climática de suporte
- A proximity-based approach for the identification of fallen species of street trees during strong wind events in LisbonPublication . Mendes, Flávio Henrique; Petean, Felipe Coelho de Souza; Correia, Ezequiel; Lopes, AntónioThe benefits of urban trees are very well known, but they can fall and cause damage, putting people’s lives at risk. There are few studies on the vulnerability of species to falling. In Lisbon (Portugal), fallen trees have been recorded since 1990 without, however, the identification of the species, knowledge of which is fundamental for improving their management. This study aimed to identify the tree species most vulnerable to falling in Lisbon through a proximity-based approach of known species, since the city has 47,713 inventoried trees, of which only 26,595 (55.7%) were identified. Four criteria were designed to presume the species: (i) the tree must be within 15 m from the street median axis; (ii) at least three individuals within 30 m from the occurrence must belong to the same species; (iii) the surrounding species must be representative in the street (>50%); and (iv) visual identification of avenue medians. Through this approach, considering 3767 fallen trees, it was possible to identify 736 cases, representing 19.5% of all occurrences throughout the studied time and representing 43 different species. Species like Morus nigra L., Tipuana tipu (Benth.) Kuntze, Liriodendron tulipifera L., Prunus cerasifera Ehrh., and Koelreuteria paniculata Laxm. were most vulnerable. Additionally, in 57.7% of cases (425 fallen trees), the wind speed 12-h before the occurrence was greater than 7 m s−1 . This research will provide important data for urban planners seeking to maximize the ecosystem services of urban trees.
- Local Weather Types by thermal periods: deepening the knowledge about Lisbon’s urban climatePublication . Reis, Cláudia; Lopes, António; Correia, Ezequiel; Fragoso, MarceloUrbanized hot spots incorporate a great diversity of microclimates dependent, among other factors, on local meteorological conditions. Until today, detailed analysis of the combination of climatic variables at local scale are very scarce in urban areas. Thus, there is an urgent need to produce a LocalWeather Type (LWT) classification that allows to exhaustively distinguish di erent urban thermal patterns. In this study, hourly data from air temperature, wind speed and direction, accumulated precipitation, cloud cover and specific humidity (2009–2018) were integrated in a cluster analysis (K-means) in order to produce a LWT classification for Lisbon’s urban area. This dataset was divided by daytime and nighttime and thermal periods, which were generated considering the annual cycle of air temperatures. Therefore, eight LWT sets were generated. Results show that N and NW LWT are quite frequent throughout the year, with a moderate speed (daily average of 4–6 m/s). In contrast, the frequency of rainy LWT is considerably lower, especially in summer (below 10%). Moreover, during this season the moisture content of the air masses is higher, particularly at night. This methodology will allow deepening the knowledge about the multiple Urban Heat Island (UHI) patterns in Lisbon.
- Heatwaves and summer urban heat islands: a daily cycle approach to unveil the urban thermal signal changes in Lisbon, PortugalPublication . Oliveira, Ana; Lopes, António; Correia, Ezequiel; Niza, Samuel; Soares, AmílcarLisbon is a European Mediterranean city, greatly exposed to heatwaves (HW), according to recent trends and climate change prospects. Considering the Atlantic influence, air temperature observations from Lisbon’s mesoscale network are used to investigate the interactions between background weather and the urban thermal signal (UTS) in summer. Days are classified according to the prevailing regional wind direction, and hourly UTS is compared between HW and non‐HW conditions. Northern‐wind days predominate, revealing greater maximum air temperatures (up to 40 °C) and greater thermal amplitudes (approximately 10 °C), and account for 37 out of 49 HW days; southern‐wind days have milder temperatures, and no HWs occur. Results show that the wind direction groups are significantly different. While southern‐wind days have minor UTS variations, northern‐wind days have a consistent UTS daily cycle: a diurnal urban cooling island (UCI) (often lower than –1.0 °C), a late afternoon peak urban heat island (UHI) (occasionally surpassing 4.0 °C), and a stable nocturnal UHI (1.5 °C median intensity). UHI/UCI intensities are not significantly different between HW and non‐HW conditions, although the synoptic influence is noted. Results indicate that, in Lisbon, the UHI intensity does not increase during HW events, although it is significantly affected by wind. As such, local climate change adaptation strategies must be based on scenarios that account for the synergies between potential changes in regional air temperature and wind.
- Variability and trends of the rainy season in West Africa with a special focus on Guinea-BissauPublication . Mendes, Orlando; Correia, Ezequiel; Fragoso, MarceloThis study provides a novel assessment of trends in rainy season behavior (1981–2020) in West Africa by analyzing highresolution rainfall data from CHIRPS 2.0. Additionally, it presents the frst comprehensive study of rainy season characteristics in Guinea-Bissau, based on an analysis of the country's available observational data, over the same period. The agronomic method was used to determine the rainfall onset, while the soil water balance was used to calculate the cessation of the rainy season. The fndings indicate that the onset of the rainy season in West Africa progresses from south to north, beginning around 8°N in May and advancing to approximately 16°N by July and early August. The cessation of the rainy season follows an opposite, north-to-south trajectory, typically starting at 16°N in late September or early October and reaching 8°N by November and early December. This regional pattern is associated with the seasonal movements of the Intertropical Front. From 1981 to 2020, the onset, cessation, and duration of the rainy season in West Africa have exhibited signifcant variability. Although statistically signifcant trends are limited, these shifts still afect agricultural planning and crop planting schedules, underscoring the importance of continuous monitoring. The standard deviation in the onset of the rainy season ranges from 4 to 55 days, while the cessation shows less variability, spanning between 3 and 21 days. Meanwhile, the number of rainy days varies from 52 in the northern part of the study area to over 200 days in the southern regions. In Guinea-Bissau, rains typically start between 15–30 June each year, with notable diferences between the northern and southern parts of the country. The average cessation occurs between the frst and second weeks of November. Evolutionary trends suggest a slightly delayed onset of rainfall, with more stability in the cessation dates, leading to a slight reduction in the length of the rainy season.