Browsing by Author "Matzarakis, A."

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Open Access
The application of the physiologically equivalent temperature to determine impacts of locally defined extreme heat events within vulnerable dwellings during the 2020 summer in Ankara
(Elsevier, 2022-03-09) Santos Nouri, A.; Charalampopoulos, I.; Matzarakis, A.
This study addresses the limited work related to Heat Stress (HS) vulnerability within indoor/outdoor contexts and its relationship with local Extreme Heat Events (EHEs). Centred upon Ankara, the study focuses on building upon its weaker approach to human thermophysiological vulnerabilities in an era of climate change, and unregulated urban densification. Through newly defined local EHEs, the physiologically equivalent temperature (PET) (and its cumulative derivatives), were utilised to develop the limited approaches that utilise Energy Based Models in the scope of EHE risk management. The study was undertaken by processing hourly data from 2008 to 2020 from Ankara's Meteorological Station, and Esenboga Meteorological Station. At a finer 10 min resolution, an interior Kestrel Heat-stress Station was used to assess summer thermal conditions in 2020 within a thermally vulnerable, yet still very frequent, residential Turkish construction typology. Among other outcomes, the results indicated the permanency of indoor PET that remained above 27 °C during non EHE periods. In the case of a Very Hot Day (VHD33), PET remained between 29 and 32.9 °C for almost 24 h. The thermal index also indicated how forced convective cooling led to indoor reductions of PET by 3–4 K, and in duration of such HS levels to less than 2 h. © 2022
Open Access
Approaching environmental human thermophysiological thresholds for the case of Ankara, Turkey
(Springer, 2020-10-27) Santos Nouri, Andre; Afacan, Yasemin; Çalışkan, O.; Tzu-Ping, L.; Matzarakis, A.
The disclosed study undertook a ‘human centred-approach’ that ascertained and categorised environmental human thermophysiological risk factors by relating them to the human biometeorological system through the use of three widely utilised energy balance model (EBM) indices, the physiologically equivalent temperature (PET), the modified PET, and the universal thermal climate index (UTCI). The disclosed assessment was carried out over the past decade (i.e., 2010–2019) with a 3-h temporal resolution for the case of Ankara through two WMO meteorological stations to compare both local urban and peri-urban environmental conditions. The study recognised extreme annual variability of human physiological stress (PS) during the different seasons as a result of the biometeorological processing of the singular variables, which in the case of average PET for both stations, varied by up to 75 °C between the winter and summer for the same annual dataset (2012). In addition, all EBMs indicated higher heat stress within the city centre that were conducive of both urban extreme heatwaves and very hot days during the summer months, with extreme heat stress levels lasting for longer than a week with PET values reaching a maximum of 48 °C. Similar cold extremes were found for the winter months, with PET values reaching − 30 °C, and average PS levels varying lower in the case of the peri-urban station.
Open Access
Assessing the influence of street configurations on human thermal conditions in open balconies in the Mediterranean climate
(Elsevier, 2021-10-04) Rodríguez-Algeciras, J.; Tablada, A.; Nouri, Andre Santos; Matzarakis, A.
Heat stress in the built environment has become a serious health and comfort issue, given the increases in Urban Heat Island effects, and augmenting impacts associated to climate change. This study deals with the potential correlations between human thermal conditions, the encircling microclimate, and the physical structure of the city. Through long-term numerical simulations, the disclosed study analyses the influence of the urban street configurations on the thermal bioclimate within urban canyons, specifically upon open balconies in the most populated district of Barcelona: The Eixample. The simulated thermal conditions were carried out in the human biometeorological RayMan Pro model using local climatic data, to determine the Physiologically Equivalent Temperature (PET) within four generated scenarios, with similar morphological properties of the Eixample district. The findings reveal that streets with axes oriented NS and SE-NW provide the best thermal conditions for balconies, achieving acceptable PET values (18 °C < PET <29 °C) on both façades. On the other hand, EW streets presented high thermal stress conditions (over 43,4% of the time) for those balconies located in the north side of the canyon. Open balconies at heights below 12 metres are the most comfortable ones during summer daytime, with acceptable thermal conditions that range between 50,4% and 82,5% of the time. The highest frequencies of acceptable thermal conditions were found on balconies located at 6 metres and 9 metres high on the east, south and southeast façades of the NS, EW and NE-SW oriented streets respectively (from 77% to 83% of the time). These configurations provide the most suitable thermal conditions during the studied summer periods by having frequencies of heat stress below 20%. Our results and recommendations contribute to bridge the gap between human biometeorology, public health, and architectural and urban planning. Some areas of its direct application are the use of balconies in periods of confinement; decision-making on the sale or rental of apartments; and the promotion of bioclimatic retrofit projects at an urban and architectural scale supported by local governments.
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 Authors
Open Access
Detection and quantification of seasonal human heat and cold stress frequencies in representative existing and future urban canyons: the case of Ankara
(Springer Wien, 2023-05-27) Nouri, Andre Santos; Charalampopoulos, I.; Afacan, Yasemin; Matzarakis, A.
Based upon a ‘human-centred approach’, combinations of existing and new methodologies were applied to determine how Ankara’s morphological characteristics influenced the magnitude/frequency of Cold Stress (CS) and Heat Stress (HS) to detect/quantify seasonal and yearly human thermal stress frequency. To quantify these conditions upon the human biometeorological system, the Physiologically Equivalent Temperature (PET) was utilised by processing climatic variables from Ankara’s Meteorological Station (AMS). In situ assessments of human thermophysiological thresholds were undertaken within characteristic existing/future Urban Canyon Cases (UCCs), with a further stipulation of three interior Reference Points (RPs). Indoor PET values were moreover calculated within a stereotypical vulnerable residential dwelling. Seasonal frequencies revealed that winter PET values frequently ranged between 0.0 and − 19.9 °C, with corresponding summer values frequently ranging between 35.1 and 46.0 °C. Accounting for Ankara’s urban morphology, yearly frequency of No Thermal Stress remained at ~ 48%, CS remained at ~ 26%, and HS ~ 28%. HS varied the most between the eight evaluated Aspect Ratios (ARs). It reduced by up to 7.1% (114 min) within the Centre (RP$_{C}$) area of UCCs with an orientation of 90°. Out of twelve orientations, the highest HS frequency took place between 105 and 135°. Including in UCC$_{3.50}$, the frequency of HS almost always remained above 72% (2592 min).
Open Access
Establishing initial urban bioclimatic planning recommendations for Ankara to address existing and future urban thermophysiological risk factors
(Elsevier, 2023-05) Nouri, A. Santos; Rodriguez-Algecíras, J.; Matzarakis, A.
Focused on the case of Ankara, human thermophysiological thresholds were investigated in association with typical morphological characteristics to determine the frequency of seasonal Heat/Cold Stress. The study further developed methodical means to better understand the relationship with local radiation exposure within in-situ settings, allowing for the better understanding of seasonal thermophysiological exposure upon human biometeorology. To approach future vulnerability and frequency of thermophysiological stress, daily EURO-CORDEX data was processed to determine Representative Concentration Pathway scenario projections (for air temperature and Physiologically Equivalent Temperature (PET)). The study highlighted the already significant urban frequencies of heat stress (ranging up to 82.7%) due to all districts witnessing an elevated frequency of low aspect ratios. The fewer mid-range aspect ratios also revealed to be frequently in orientations with higher heat stress susceptibilities (i.e., between 105° and 150°). Bioclimatic planning recommendations were presented for Ankara. Nevertheless, given the high vulnerability for existing/future urban human health and welfare, these recommendations were further associated with the call for immediate heat action plans and heat warning/mapping systems. In these first type of projections for Ankara, even for the milder/stabilization future scenario by 2100, PET based projections revealed frequencies remaining at 100% between 35.1 °C–41.1 °C, with further values exceeding 46.1 °C.
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.
Open Access
Investigating the impacts of shaded outdoor spaces on thermal adaptation and cognitive performance of university students in classroom environments
(Springer Science and Business Media Deutschland GmbH, 2023-12) Gündoğdu, Betül; Nouri, A. Santos; Afacan, Yasemin; Matzarakis, A.
Shading strategies are effective means to reduce urban risk factors such as the Urban Heat Island (UHI) effect. The influence of shaded outdoor spaces on university students’ thermal adaptability and cognitive performance is limited researched. The study aims at evaluating the effect of shaded outdoor spaces upon thermal comfort; and, linking such results upon university students’ cognitive performance in a classroom environment with natural ventilation. A case study was conducted with students the ages of 19–22 at Bilkent University in Ankara, during the mid-season in October. The quantitative microclimatic conditions of the university campus’s unshaded/shaded areas and indoor studios were obtained through Physiologically Equivalent Temperature (PET) index. The qualitative evaluation was undertaken by the adaptive model and thermal comfort survey. D2 test of attention was conducted to measure cognitive performance of students. This study revealed that the shade may increase thermal adaptation with the lowest mean PET of 18.7°C, while the highest mean PET of 33.2°C was obtained in sun-exposed space. Also, experiencing shaded outdoor space contributed to an improvement in concentration performance (CP) of students resulting in the mean CP score of 182.8, while those with sun-exposed outdoor space experience had the mean CP score of 167.6 within studios.
Open Access
Investigating the relationship of outdoor heat stress upon indoor thermal comfort and qualitative sleep evaluation: The case of Ankara
(MDPI, 2023-09-06) Ahan, Merve Münevver; Nouri, Andre Santos; Matzarakis, A.
The necessity of exploring the relationship between sleep quality and the thermal environment has amplified regarding increasing heat stress risk on the human body due to climate change, particularly in vulnerable uninsulated buildings in Ankara. Within this scope, this study investigated occupants’ sleep quality and human thermal comfort in insulated and uninsulated buildings under three local extreme heat event thresholds: (1) typical summer days (TSD25), (2) very hot days (VHD33), and lastly, (3) heat wave events (HWE31). Within a two-tiered approach to thermal comfort evaluations, the human thermal comfort of occupants was identified through the calculation of physiologically equivalent temperature (PET) from the climatic data of local meteorological stations. The psychological thermal comfort and sleep quality of participants were evaluated by questionnaires during each heat event. The results of this study demonstrated that the physiological thermal load of the participants was highest during VHD33s, given that both outdoor and indoor PET values presented their highest values within VHD33 events. Furthermore, the outdoor PET values reached extreme heat stress based on physiological stress grades with 43.5 °C, which indicated the exacerbated vulnerability of Ankara during extreme heat events. The PET values were consistently higher in uninsulated buildings than in insulated buildings. Also, most of the mean psychological thermal comfort votes and sleep quality votes were better in uninsulated buildings than in insulated ones during TSD25s and HWE31s, while it was the opposite within extreme conditions of VHD33s. The outputs of this study contribute to interdisciplinary efforts to attenuate the existing and impending risks of climate change on human life by defining the influence of increasing outdoor heat stress on indoor spaces, thermal comfort, and the sleep quality of occupants.