Planning with urban climate in different climatic zones

The main climatic changes induced by settlements are discussed first, in order to introduce the main objectives of this paper: to show the importance of urban climate information for planning and to emphasize that adequate measures “to plan and to build with climate”vary according to the macroclimate of the urban area. The urban radiation and energy balances, heat islands, wind conditions, air pollution and thermal comfort are dealt with in detail. Studies of the last decades that consider the economic and health benefits of using climatic information are also reviewed., Urban climates should be a routine consideration of land use planning processes in order to attain a better “climatequality” in settlements. We suggest measures that can reduce the negative effects or take advantage of the positive consequences of urbanizationon climate in different climate zones (cold, warm and humid, warmand arid, contrasting seasons’ climate).Resumen: Se discuten primero los principales cambios climáticos inducidospor los asentamientos, con el fin de establecer los principales objetivosde este trabajo: mostrar la importancia de la información climáticapara la planificación urbana y hacer hincapié en que las medidas adecuadas“para planificar y construir con el clima” varían de acuerdo conel clima del área donde está localizada la ciudad. Los balances de radiacióny energía urbanos, la isla de calor, las condiciones del viento, lacontaminación del aire y el confort térmico se tratan en detalle. Tambiénson revisados los estudios de las últimas décadas que consideran losbeneficios económicos y para la salud de la utilización de informaciónclimática. La consideración del clima urbano debe formar parte de losprocesos de ordenamiento territorial para lograr una mejor “calidad delclima” en los asentamientos. Se proponen también medidas que puedenreducir los efectos negativos o aprovechar las ventajas de urbanizar unazona basándose en su clima (frío, cálido y húmedo, cálido y árido, contrastesestacionales del clima)

Planning procedures towards high climatic quality cities. Example referring to Lisbon

The different stages of research on high climatic quality city are presented in this paper: acquisition of appropriate urban climate information, analysis of different urban climate features and selection of planning strategies (accordingly with the climate zone). Then, with the aid of a GIS, systematic guidelines for planning can be given. As a result, different types of benefits for city dwellers are to be expected (comfort, health, economic). Lisbon is presented as a case study. It is shown how the “translation” of the knowledge of Lisbon’s urban climate into simple guidelines for urban planning in order to mitigate the urban heat island, promote ventilation and increase air quality, was carried out. To this end, maps of the physical features of the city of Lisbon were drawn, synthesised into “urban homogeneous units” map. Climate guidelines are specified for each of the six groups of units (brought together according to urban morphology, topography and position in town

A bottom-up interdisciplinary research approach for thermal sensitive urban design in an era of climate change - the case of Lisbon

Tese de Doutoramento em Urbanismo, com a especialização em Urbanismo apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Doutor.Na cidade contemporânea, factores como as elevadas temperaturas e a intensidade dos efeitos da ilha de calor em meio urbano, têm vindo a revelar proeminente desconforto térmico e importantes preocupações com a saúde durante os períodos anuais de maior estímulo térmico. Para além destes riscos já existentes e inerentes ao clima urbano, as projecções das alterações climáticas apontam para uma exacerbação destes factores de risco ao longo do Séc. XXI. Muito embora as avaliações e outputs top-down tenham revelado informação de carácter imperativo relativamente a tais fenómenos, a emergência da agenda de adaptação às alterações climáticas veio também incentivar a comunidade científica internacional a maturar e a desenvolver abordagens bottom-up mais incisivas, com vista a fazer frente aos factores de risco locais. Assim sendo, a perspectiva de "localidade" tem vindo a ganhar um novo significado para disciplinas como o urbanismo e o design urbano, quando confrontados com aspectos como a segurança, o conforto térmico humano e a prosperidade do meio urbano contemporâneo. Todavia e, atendendo ao seu carácter emergente, as abordagens bottom-up ainda se encontram numa fase inicial e, consequentemente, relativamente limitadas, tendo em conta a distância existente entre a teoria e a aplicação prática. Como resposta, esta tese efectua uma abordagem bottom-up e uma reflexão acerca do modo como a união entre a climatologia urbana e o design do espaço público urbano, enquanto campos distintos, pode ser fortalecida. Tal fortalecimento visa investigar de forma directa sobre a possibilidade de "localmente", o conforto térmico humano em meio urbano exterior, ser melhorado através de práticas interdisciplinares apoiadas no conhecimento científico. Tendo em consideração o caso de Lisboa, esta investigação analisa a forma como esta abordagem pode suplantar questões como a incerteza climática/aplicacional e, consequentemente: (i) traduzir-se em linhas de orientação para o urbanismo e para o design urbano local, que poderão ser aplicadas/implementadas em múltiplas circunstâncias e contextos urbanos; visando ainda, (ii) auxiliar especialistas "não-climatólogos" a realizar levantamentos bioclimáticos (baseados em dados locais e/ou na informação obtida a partir da estação meteorológica) com o intuito de determinar/atenuar os factores de risco de stress associados ao calor e ao frio num determinado contexto exterior. Consequentemente e, focado numa abordagem bottom-up que para além disso considera outputs relevantes a partir de avaliações top-down, o design do espaço público é retratado como sendo uma ferramenta indispensável, com vista a assegurar "localmente" um meio urbano activo, confortável e seguro, tanto no presente, quanto num futuro que se afigura incerto.ABSTRACT: Within the existing city, factors such as elevated urban temperatures and intensities of urban heat island effects are already revealing prominent thermal discomfort and health concerns during annual periods of more accentuated climatic stimuli. In addition to these exiting risks upon the urban microclimate, climate change projections indicate further exacerbations of such risks factors throughout the course of the twenty-first century. Although top-down assessments and disseminations have revealed imperative information with regards to such phenomena, the emergence of the climate change adaptation agenda has also arguably propelled the scientific international community to further mature bottom-up approaches to address local risk factors. As such, the perspective of ‘locality’ has been one which has gained new meaning for disciplines such as urban planning and design when considering the climatic safety, human thermal comfort, and prosperity of the contemporary public realm. Nevertheless, and resultant of its emerging nature, bottom-up approaches are still somewhat limited in terms of its existing breadth between theory and application and practice. As a response, this thesis undertakes a bottom-up approach and discusses how the union between the individual fields of urban climatology and public space design can be fortified. Such a fortification is directly aimed at investigating how local outdoor human thermal comfort can be improved through an interdisciplinary practice which is backed by scientific know-how and practice. Considering the case of Lisbon, this research deliberates upon how such an approach can overcome issues of climatic and applicative uncertainty, and can: (i) be translated into local design and planning guidelines which can be applied within numerous different urban circumstances; and (ii) aid non-climatological experts to undertake bioclimatic surveys (based both upon site and/or meteorological station data) to determine, and attenuate, local heat and cold stress risk factors within a particular outdoor context. Accordingly, and centred upon a bottom-up approach, which moreover considers important disseminations from top-down assessments, public space design is portrayed as an imperative tool to locally ensure an active, comfortable and safe public realm, both presently, and in an uncertain future.N/

Lisbon Urban Heat Island Updated: new Highlights about the Relationships between Thermal Patterns and Wind Regimes

Urban growth implies significant modifications in the urban climate. To understand the influence of the city of Lisbon on the urban boundary layer, a mesoscalemeteorological network was installed in 2004. The main goals of the present study are to update the results of the research published in 2007 and to bring more precise information about the relationship between the Urban Heat Island (UHI) and the regional and local wind systems. The highest frequencies of the UHI were found in the city centre (Restauradores). In the green park ofMonsanto, the highest frequency occurred between −2 and0∘C.During the summer, the effect of the breezes was observed in Bel´em, lowering the temperature.The“strong” UHI (intensity >4∘C) occurredmore often during the summer, with median values of 2∘C by night and 1.8∘C by day.The highest frequencies of UHI occurred for winds between 2 and 6m/s and were not associated with atmospheric calm, as pointed out in the literature.Winds above 8m/s inhibit the occurrence of strong UHI in Lisbon. Summer nighttime strong UHI should be further investigated, due to the heat stress consequences on the population and probable increase of energy consumption.info:eu-repo/semantics/publishedVersio

An urban climate-based empirical model to predict present and future patterns of the Urban Thermal Signal

Air temperature is a key aspect of urban environmental health, especially considering population and climate change prospects. While the urban heat island (UHI) effect may aggravate thermal exposure, city-level UHI regression studies are generally restricted to temporal-aggregated intensities (e.g., seasonal), as a function of time-fixed factors (e.g., urban density). Hence, such approaches do not disclose daily urban-rural air temperature changes, such as during heatwaves (HW). Here, summer data from Lisbon's air temperature urban network (June to September 2005-2014), is used to develop a linear mixed-effects model (LMM) to predict the daily median and maximum Urban Thermal Signal (UTS) intensities, as a response to the interactions between the time-varying background weather variables (i.e., the regional/non-urban air temperature, 2-hours air temperature change, and wind speed), and time-fixed urban and geographic factors (local climate zones and directional topographic exposure). Results show that, in Lisbon, greatest temperatures and UTS intensities are found in 'Compact' areas of the city are proportional to the background air temperature change. In leeward locations, the UTS can be enhanced by the topographic shelter effect, depending on wind speed - i.e., as wind speed augments, the UTS intensity increases in leeward sites, even where sparsely built. The UTS response to a future urban densification scenario, considering climate change HW conditions (RCP8.5, 2081-2100 period), was also assessed, its results showing an UTS increase of circa 1.0 °C, in critical areas of the city, despite their upwind location. This LMM empirical approach provides a straightforward tool for local authorities to: (i) identify the short-term critical areas of the city, to prioritise public health measures, especially during HW events; and (ii) test the urban thermal performance, in response to climate change and urban planning scenarios. While the model coefficient estimates are case-specific, the approach can be efficiently replicated in other locations with similar biogeographic conditions.info:eu-repo/semantics/publishedVersio

Important variables when studying the influence of particulate matter on health.

info:eu-repo/semantics/publishedVersio

Sea Breeze Front and Outdoor Thermal Comfort during Summer in Northeastern Brazil

Characterizing the behaviour of the sea breeze phenomenon is the foremost factor in the reduction in the heat stress and the achievement of the pleasant environment in coastal cities globally. However, this seminal study shows that the Sea Breeze Front (SBF) development can be related to an increase in outdoor thermal discomfort in a northeastern Brazilian city during summer. We explored the relationship between SBF and thermal comfort conditions using in situ meteorological observations, the SBF identification method, local climate zones (LCZs) classification, and the Physiological Equivalent Temperature (PET) thermal comfort index. SBF days and Non-SBF days were characterized in terms of weather conditions, combining meteorological data and technical bulletins. SBF days included hot and sunny days associated with the centre of the Upper Tropospheric Cyclonic Vortices (UTCV). In contrast, Non-SBF days were observed in UTCV’s periphery because of cloudy sky and rainfall. The results showed that the mean temperature and PET in the SBF days were 2.0 C and 3.8 C higher, respectively, compared to Non-SBF days in all LCZ sites. The highest PET, of 40.0 C, was found on SBF days. Our findings suggest that SBF development could be an aggravating factor for increasing heat stress of the people living in the northeastern coast of the Brazilian city, after SBF passage.info:eu-repo/semantics/publishedVersio

Local weather types by thermal periods: deepening the Knowledge about Lisbon’s Urban Climate

Urbanized 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.info:eu-repo/semantics/publishedVersio

Human thermo-physiological comfort assessment in Lisbon by local climate zones on very hot summer days

Extreme heat is a current and future issue on urban areas, with negative impacts on health and quality of life (increasing morbidity and mortality rates). This paper analyses day (12:00–15:00 h) and nighttime (00:00–03:00 h) thermophysiological comfort (TC) conditions by Local Climate Zones (LCZ) in Lisbon during a particular Local Weather Type (LWT), very hot summer days. For this, 13 different microscale sample areas were chosen covering urban and non-urban land cover classes (LCZs 1–3, 4–6, 8, 9, A and B). Universal Thermal Climate Index (UTCI) and Mean Radiant Temperature (MRT) were modeled on SkyHelios software for 163 days between 2008 and 2014. Results show that during the day all urban LCZ samples depict the same average TC conditions (average UTCI of 34°C—strong heat stress) and densely wooded areas are 2°C cooler (average UTCI of 32°C—moderate heat stress). However, compact areas (LCZs 1–3) with low sky view factor and some vegetation (street trees) display lower percentages of area with higher thermo-physiological discomfort (TD) levels (83% with strong heat stress against 98% in LCZs 8 and 9 and 100% in LCZs 4–6). When considering the hottest days (air temperatures equal or above 35°C—75th percentile), the moderate heat stress class disappears in all samples and the very strong heat stress class appears only on urban areas, occupying between 12% and 16% on LCZs 1–3, 10%–22% on LCZs 4–6, 16%–22% on LCZs 8 and 9 on LCZ 9. During the nighttime period all samples show no thermal stress, favoring nocturnal physiological recovery. TC conditions in Lisbon are strongly influenced by solar radiation and wind, which explains the need to increase the shading area, preferably by trees, and to promote and preserve ventilation paths.info:eu-repo/semantics/publishedVersio