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Intensity and form of the Urban heat island in Barcelona

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Abstract

A statistical analysis of the differences between the daily minima in the centre of Barcelona and those of the airport, supplemented by temperature readings taken along a number of transects through the urban area, have revealed the intensity of the heat island effect, which reaches a maximum intensity of 8°C. It was also possible to plot the spatial configuration of the latter.
... Traditional UHII quantification is defined by the air temperature difference at a fixed specifically in situ point in the city and suburbs (Moreno-garcia 1994;Magee et al. 1999;Chow and Roth 2006). This traditional definition of UHII cannot be represented as a phenomenon for the whole city because it uses local climate characteristics data, and it is difficult to observe various micro-scale temperature perturbations due to multiple heat sources in UHIs (Oke 2006). ...
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Using satellite data, it is possible to precisely observe the micro-scale structure of the surface urban heat island (SUHI) and its change over time. A new approach for clustering complex heat islands patterns was proposed using a combination of the operational method and the Jenks natural breaks method. Through this, we defined the spatial range of heat island and the core with the higher temperature in it and also applied for Busan, a coastal city, and Daegu, an inland basin city in the Korean peninsula. SUHI existed in one of the following three types: single-core heat island with one core, multi-core heat island with two or more cores, and acentric heat island (AHI) without a core. Busan and Daegu had different spatiotemporal SUHI variations. Variation of the SUHI pattern in Busan was markedly different according to seasonal changes, and in Daegu, the difference between day and night was more pronounced than seasonal changes. In Busan, SUHIs bordered by mountains in the inner-city area tended to move closer to the sea in winter. Several SUHIs formed in the shape of basin during the daytime were merged into one large heat island in the downtown of the city at nighttime in Daegu. These spatiotemporal changes of SUHI were also consistent with the variation of near-surface temperature (NST). In addition, the study case had a high correlation with the distribution and intensity of SUHI averaged over 5 years. Although there are several cores in SUHIs did not appear in the 5-year average data, which was associated with its inter-annual variation, the distribution of SUHIs was agreed well with the 5-year average NST pattern.
... The Intergovernmental Panel on Climate Change of the United Nations stated that "it is wellknown that compared to non-urban areas urban heat islands raise night-time temperatures more than daytime temperatures" [17]. For example, Barcelona, Spain is 0.2 °C cooler for daily maxima and 2.9 °C warmer for minima than a nearby rural station [18]. First report of the UHI by Luke Howard, who is considered as first person who deals with UHI problematics, in the late 1810s said that the urban center of London was warmer at night than the surrounding countryside by 2.1 °C [19]. ...
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Work of researchers from various areas is focused on problematics of urban heat islands. Its importance is rising with the global climate change. The difference of the air temperatures within the area can be also caused by the measurement error. Usual error is not the accuracy of the sensor, but the radiation shield or location of the weather station. In this case, averaged difference can be up to 80 %. Difference of temperatures between the weather stations within the analyzed area can vary from 0.2 up to 6 °C. Difference depends usual on the size of the city and the location influenced by the surrounding geomorphology. In this paper three different radiation shields are compared which influenced the measurement and analyzed are also the results from four different weather stations, two of them are within the University of Zilina campus. One of them is placed on the roof, which is a usual location for the solar radiation measurement; the second one is placed on the grass land at the end of the campus. Other two stations belong to the national weather institute. Comparison is made for two very hot days of August 2020. Averaged difference was 0.3 °C for the whole month and 0.5 °C for selected days.
... According to recent studies, the city is particularly vulnerable to climate change related threats, including sea-level rise, increasing temperatures including urban heat islands, the loss of biodiversity, and more frequent and intense drought periods (City of Barcelona, 2017). The heat island effect is so significant that temperatures in the city centre may be up to 8°C higher than the surrounding less urbanised areas (Moreno-garcia, 1994). Black asphalt and car emissions bear the majority of responsibility for the heat islands in Barcelona (Rueda, 2016), with 60% of public land being devoted to automobiles (City of Barcelona, 2015), causing a lack of green space in the urban environment (WHO Regional Office for Europe, 2016). ...
Thesis
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The future of sustainable urban mobilities is a topic that is of increasing around the world. Dominant discussions focus on what these future urban mobilities will constitute and whether they will achieve targets to successfully decarbonise and to minimise the effects of climate change. Historically, transportation in our societies has mainly been approached from a positivist worldview that has attempted to understand the future through predictive models based on historical trends and relational extrapolation. However, the ambiguity created by the emergence of new transport innovations, such as self-driving cars, micromobility, battery-electric vehicles, and digital services, has created a high level of uncertainty about the future. This Industrial PhD thesis takes this challenge as a starting point. First, the thesis rejects the dominance of positivistic transport-planning approaches within the urban mobility discourse. Second, it explores how to deploy architectural modes of enquiry and tools of visualisation to develop novel methods for the development of sustainable mobilities for the future. A ‘research-through-design’ methodology is employed to incorporate architectural spatial knowledge and methods into mobilities research. This methodology is elaborated through a programmatic design research approach that generates knowledge on sustainability transitions in mobility through the development of design experiments that utilise mixed, and transdisciplinary methods.
... Estos resultados primarios sugieren que la intensidad de la isla de calor parece mayor en condiciones meteorológicas de frío ambiental, y es menor en condiciones de más calor. Esto resulta coherente con la hipótesis según la cual los días más fríos del año son más propicios para el establecimiento de una isla de calor típica (Moreno, 1994;Montávez, Rodríguez y Jiménez, 2000), ya que aumenta la combustión producida por las calefacciones de uso doméstico y aumenta, en general, la actividad combustiva urbana, lo que se traduce en un incremento de la temperatura ambiental de la ciudad respecto de su periferia rural. Aunque no hay un consenso claro en torno a la estacionalidad de la isla de calor, otros autores señalan que puede ser más intensa en verano (Kolokotroni y Giridharan, 2008;Klysik y Fortuniak, 1999). ...
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Se presenta un nuevo estudio del fenómeno de isla de calor urbana aplicada a la ciudad mallorquina de Inca, con el objetivo de ampliar y verificar los resultados de los trabajos precedentes. A partir del método de los transectos móviles, se han realizado mediciones en cuatro respectivas estaciones del año meteorológico: invierno, otoño, verano y primavera. Los resultados confirman islas de calor nocturnas que manifiestan diferencias de temperatura de hasta 5,7º C entre el sector central de la ciudad y su entorno rural. La actividad antropogénica urbana en Inca, la anchura reducida de ciertas calles, la altura de los edificios y la estabilidad atmosférica, son factores combinados que juegan a favor de este incremento térmico diferencial, más acusado en condiciones de frío ambiental (otoño e invierno) que de calor (primavera y verano). Los resultados son de utilidad para trabajos de planificación urbana con criterios ambientalesresumen, de no más de 150 palabras (en español e inglés), describirá el objetivo de la investigación, la metodología empleada, los resultados más destacados y las principales conclusiones.
... Estos resultados primarios sugieren que la intensidad de la isla de calor parece mayor en condiciones meteorológicas de frío ambiental, y es menor en condiciones de más calor. Esto resulta coherente con la hipótesis según la cual los días más fríos del año son más propicios para el establecimiento de una isla de calor típica (Moreno, 1994;Montávez, Rodríguez y Jiménez, 2000), ya que aumenta la combustión producida por las calefacciones de uso doméstico y aumenta, en general, la actividad combustiva urbana, lo que se traduce en un incremento de la temperatura ambiental de la ciudad respecto de su periferia rural. Aunque no hay un consenso claro en torno a la estacionalidad de la isla de calor, otros autores señalan que puede ser más intensa en verano (Kolokotroni y Giridharan, 2008;Klysik y Fortuniak, 1999). ...
Article
Full-text available
Se presenta un nuevo estudio del fenómeno de isla de calor urbana en la ciudad mallorquina de Inca, con el objetivo de ampliar y verificar los resultados de los trabajos precedentes. A partir del método de los transectos móviles, se han realizado mediciones en cuatro estaciones del año meteorológico: invierno, otoño, verano y primavera. Los resultados confirman islas de calor nocturnas que manifiestan diferencias de temperatura de hasta 5,7ºC entre el sector central de la ciudad y su entorno rural. La actividad antropogénica urbana en Inca, la anchura reducida de ciertas calles, los edificios altos, la escasez de cubierta vegetal y la estabilidad atmosférica, son factores combinados que juegan a favor de este incremento térmico diferencial, aparentemente más acusado en condiciones de frío ambiental que en condiciones de calor. Los resultados son de utilidad para trabajos de planificación urbana con criterios de sostenibilidad ambiental.
... When using the urban scheme, the largest temperature changes occur in summer at night with smaller changes in the daytime (figure not shown). These changes typically agree well with observation based studies, which also find urban heat island enhancements are larger at night than during daytime [93,94]. High-resolution global ECLand simulations (∼1 km horizontal) show expected skin and 2 m temperature enhancements over both large and small urban conurbations (Figure 26). ...
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Time trends and their statistical significance for daily minimum, Tmin, and maximum, Tmax, temperatures recorded at the Fabra Observatory (Barcelona) along 102 years (1917–2018) permit to analyse the evolution of every one of the 365 calendar days along the recording period. Relevant changes in the daily temperature regime have been quantified not only by time trends and the Mann–Kendall test, but also by the multifractal analysis applied to consecutive segments of daily temperature data. The evolution of several multifractal parameters (the central Hölder exponent, the spectral asymmetry and spectral amplitude, the complexity index and the Hurst exponent) provides a complementary viewpoint to describe the evolution of the thermometric regime along the 102 recorded years. At monthly scale, the effects of the climate change are characterised by significant positive trends from September to December and very moderate negative trends from April to July. With respect to changes in the calendar-day structure, it is noticeable a shift of the highest minimum and maximum daily temperature from July to August (year 2018) to the beginning of September (projections for years 2030 and 2050) and the projected highest maximum calendar-day temperature exceeding 30 °C.
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In recent years, those who create strategies and policies for urban tourist destinations have been increasingly concerned with the greater or lesser capacity to enjoy public space. Furthermore, the growth of urban areas on a global scale has caused significant changes in the (micro)climate, due to the increase in impermeable surfaces, the anthropogenic heat generated by human activities and the change in air circulation. Taking into account the increasing demands of tourists and residents and the need to improve cities in the face of climate change, the option is to design new measures and action solutions. However, the lack of quality of the input data or their (total) absence, as well as their low spatial resolution, are common. The inadequacy of structures for sharing information is also noted, which significantly limits planning and adaptation actions. This investigation aims to identify the main methods of analysis to monitor the current ability to enjoy tourism based on the integration of objective and subjective domains; and contribute to the definition of action plans which seek to mitigate and adapt the tourism sector to climate change, in the medium and long-term. To assess the validity of these assumptions, the Porto Metropolitan Area, in general, and the municipality of Porto, in particular, were used as case studies. In this investigation, different methods of information and units of analysis were combined, based on a meso approach and local scale for: (i) the identification of critical areas, in an office analysis based essentially on Big Data (i.e., Flickr photographs, AirBnB accommodation and MODIS and LANDSAT satellite imagery); (ii) the assessment of the comfort level for enjoyment in critical areas with high tourist potential through field data collection; and (iii) the identification of prioritization actions and measures to maintain tourism attractiveness in view of climate change, in the medium and long-term. This research highlights the need for more detailed information, the weak interaction between stakeholders and the limitation of resources. Thus, considering that Porto is a destination with a good climate for tourism, and committed to mitigating the effects of climate change, the proposed methodological triangulation allows to outline some measures with predictable action in the short, medium and long-term. Finally, this study aims to make some contributions at national and international level, with the likelihood of the methodological approach adopted to be replicated in other geographical areas, taking into account the particularities of each territory under analysis.
Thesis
This thesis is based on understanding and dealing with the complexity of the urban fabric and the significant role played by roofs and other anthropogenic factors in the urban climate. A singular complexity which alters the climate, leading to a high vulnerability to high temperatures in our latitudes. However, there is still a lack of knowledge when it comes to understanding the dynamics of all the processes and interactions observed within the urban boundary layer. Because of these limitations, mainly related to the urban fabric, the aim of this doctoral thesis is to advance in this line of research by attempting to thermally characterize roofs and to explore the role they play. The aim is to improve the characterization of our urban and peri-urban region by applying sustainable climate change mitigation proposals. To this end, the cartographic techniques, remote sensing data and geo-referenced modelling used have been crucial in order to achieve our objective. Firstly, we have presented different methodologies for mapping Local Climate Zones, either by means of Machine Learning or by using and reconverting existing high-resolution geoinformation datasets over our study area. Secondly, we have used these mappings along with other remote sensing techniques to run urban climate and meteorological models aiming to monitor in a very detailed way the urban thermal behavior in the Metropolitan Area of Barcelona. Using these outputs, we have been able to modify the cartographies created with the aim of developing thermal mitigation strategies in urban ecosystems and to find out to what extent the increase in temperature and associated mortality can be reduced. We are aware that this is a big challenge at all levels, not only scientifically but also at political and societal level. [IN SPANISH] CATALAN INDUSTRIAL DOCTORATE PROGRAMME - 2015 DI 0038
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Doubt exists among atmospheric scientists about current estimates of local and regional effects of urbanization on climate, but not generally about the existence of these urban effects. This paper presents a framework for discussion of various estimators, uses the framework to make the case for a particular estimator, and then uses the framework to examine possible shortcomings of other estimators which appear in the literature. The measure recommended consists of differences between observations, from urban and pre-urban periods, first stratified by synoptic weather type. The measures whose shortcomings are examined are 1) contemporaneous urban-rural differences, 2) contemporaneous upwind-downwind differences, 3) contemporaneous urban-regional ratios, 4) time trends of differences and ratios and 5) contemporaneous weekday-weekend differences. The paper is designated as a `problem analysis' because its goal is general facilitation of discussion about the problem of empirical estimation of urban effects on climate.
Modificaciones termicas en las ciudades Avance sobre la isla de calor en Barcelona', Doc. d'Andl. Geogr., Lowry, W. P. 1977. 'Empirical estimation of urban effects on climate: a problem analysis
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