Browsing by Subject "Urban climate"
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Item Open Access Assessing urban heat island effects through local weather types in Lisbon's Metropolitan Area using big data from the Copernicus service(Scopus, 2022-04-19) Reis, C.; Lopes, A.; Nouri, A. SantosIn this study UHI in Lisbon's Metropolitan Area (LMA) is analyzed through Local Weather Types (LWT) using an air temperature dataset produced by Copernicus. Over 61,000 hourly air temperature maps between 2008 and 2014 are extracted, divided into thermal seasons and LWT, and UHI is calculated by the anomaly between each raster cell and a pixel from “Low Plants” Local Climate Zone (LCZ) class. UHI daily cycle is analyzed by LWT. Statistical analysis shows that rainy days produce lower median UHI intensities (close to 0 °C), while sunny days, especially very cold winter days, produce higher UHI intensities (median values close to 1,5 °C). Analysis of the UHI pattern displays a S/SE-N/NW dichotomy in the right bank of the Tagus river and an N-S dichotomy in the Peninsula of Setúbal. The UHI effect is more pronounced in Lisbon, particularly in the riverfront area, and on the opposite bank of Tagus due to the shelter effect of frequent N winds. As previous studies have proven, UHI in LMA is mainly a nighttime phenomenon. This methodology may help decision makers to identify critical heating districts as well as weather conditions most conducive to a significant overheating of the urban atmosphere. © 2022Item Open Access Defining local extreme heat thresholds and Indoor Cooling Degree Necessity for vulnerable residential dwellings during the 2020 summer in Ankara – Part I: Air temperature(Elsevier Ltd, 2021-10-29) Andre Santos, Nouri; Çalışkan, Onur; Charalampopoulos, Ioannis; Cheval, Sorin; Matzarakis, A.This study discusses the preliminary assessment of Indoor Cooling Degree Necessity (ICDN) based upon the standard air temperature (Ta) value of 22 °C which is defined to be the standard upper mean temperature limit (Tl) for interior comfort as defined by the WHO. By considering indoor air temperature (TaI), levelled oscillations above Tl are utilised to determine indoor temperature extremes/frequencies at a 10 min temporal resolution during the months of July and August 2020 in Ankara. These recordings were undertaken through the use of an interior in-situ Meteorological Station (MS), simultaneously, an outdoor in-situ MS was also mounted outside the naturally ventilated dwelling with the identical measurement interval period. Moreover, to supplement the encompassing outdoor data collection, two WMO MSs were utilised in the study to account for both encompassing local peri-urban Esenboga (EMS) and Ankara's urban (AMS) outdoor air temperatures (TaO) at a 1 h temporal resolution. In addition to the ICDN's identified variation of Tl levels, which frequently remained between +7 °C and +10 °C during periods of accentuated urban outdoor heat stress; their direct/latent cause-and-effect relationship with newly defined local extreme heat thresholds were established. Relative to July and August 2020, a total of 19 Very Hot Days (VHD33), 10 Monthly Tropical Night (MRT20), and 4 Heatwave Events (HWE31) were determined. These thresholds further underlined the growing need to associate indoor and outdoor heat stress during local extreme heat events, particularly in more vulnerable residential contexts; and moreover, in an era of increasing heat stress as result of rapid urbanisation and climate change. © 2021 The AuthorsItem Open Access Human thermo-physiological comfort assessment in Lisbon by local climate zones on very hot summer days(Frontiers Research Foundation, 2023-05-17) Reis, C.; Nouri, Andre Santos; Lopes, A.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) thermo-physiological 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.Item Open Access In Press, Corrected Proof: Defining local extreme heat thresholds and Indoor Cooling Degree Necessity for vulnerable residential dwellings during the 2020 summer in Ankara – Part I: Air temperature(Elsevier, 2021-10-29) Nouri, Andre Santos; Çalışkan, O.; Charalampopoulos, I.; Cheval, S.; Matzarakis, A.This study discusses the preliminary assessment of Indoor Cooling Degree Necessity (ICDN) based upon the standard air temperature (Ta) value of 22 °C which is defined to be the standard upper mean temperature limit (Tl) for interior comfort as defined by the WHO. By considering indoor air temperature (TaI), levelled oscillations above Tl are utilised to determine indoor temperature extremes/frequencies at a 10 min temporal resolution during the months of July and August 2020 in Ankara. These recordings were undertaken through the use of an interior in-situ Meteorological Station (MS), simultaneously, an outdoor in-situ MS was also mounted outside the naturally ventilated dwelling with the identical measurement interval period. Moreover, to supplement the encompassing outdoor data collection, two WMO MSs were utilised in the study to account for both encompassing local peri-urban Esenboga (EMS) and Ankara’s urban (AMS) outdoor air temperatures (TaO) at a 1 h temporal resolution. In addition to the ICDN’s identified variation of Tl levels, which frequently remained between +7 °C and +10 °C during periods of accentuated urban outdoor heat stress; their direct/latent cause-and-effect relationship with newly defined local extreme heat thresholds were established. Relative to July and August 2020, a total of 19 Very Hot Days (VHD33), 10 Monthly Tropical Night (MRT20), and 4 Heatwave Events (HWE31) were determined. These thresholds further underlined the growing need to associate indoor and outdoor heat stress during local extreme heat events, particularly in more vulnerable residential contexts; and moreover, in an era of increasing heat stress as result of rapid urbanisation and climate change.Item Open Access Urban heat island data by local weather types in Lisbon metropolitan area based on Copernicus climate variables dataset for European cities(Elsevier Inc., 2022-06) Reis, Cláudia; Lopes, António; Nouri, Andre SantosHere we provide Urban Heat Island (UHI) by local weather types (LWT) maps for the Lisbon Metropolitan Area (LMA). These maps were produced from the Copernicus Land Monitoring Service climate variables dataset that contains hourly air temperature raster data for 100 European cities (2008-2017), namely Lisbon and part of its metropolitan area. Over 61000 maps (2008-2014) were extracted in NetCDF format and processed in geographic-information-systems (GIS). An urban mask was created from the recently updated Local Climate Zones (LCZ) classification for this area and a cell of the LCZ class “Low Plants” (non-urban) was chosen to calculate the temperature difference. UHI intensity was estimated using an R script. The outputs of this process were divided by thermal seasons and LWT. Ultimately, average UHI intensity by LWT was estimated. Average UHI according to meteorological conditions is available in GeoTIFF raster format (Appendix 1), with a spatial resolution of 100 × 100m pixels, as well as hourly average UHI for each LWT (Appendix 2 to 16). This data may provide valuable information for urban planners, designers and architects in the process of pinpointing recurrent hot and cool spots/neighborhoods in the city and its heating/cooling degrees. Moreover, these maps may contribute to a construction of an early warning system that anticipates which weather conditions we might expect an significant increase in thermal discomfort on those critical areas in the city. © 2022