Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.314
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-35457609

RESUMO

Urban microclimate has a direct impact on the quality of life of urban residents. Therefore, research on urban microclimates has received greater attention from contemporary scholars. At present, there is a lack of quantitative summary and review of the research in the field of urban microclimate, and it is urgent to sort out its research context and evolution. The Web of Science was used as the data source, and CiteSpace and VOSviewer software were used to analyze the urban microclimate research from 1980 to 2020. We discussed the annual trends, research countries, research institutions, key authors, highly cited publications, hot issues, and research fronts. The study found that: (1) the number of published articles on urban microclimate has experienced three stages: initial stage-slow growth period-rapid growth period; (2) European and American countries were the first to focus on urban microclimate research, while China started late but developed rapidly; (3) the research topics of urban microclimate are thermal comfort, improvement strategies, urban street canyons, and urban heat island effect; (4) the frontiers of urban microclimate include research on urban microclimate and building energy, ecosystem services, and urban parks.


Assuntos
Bibliometria , Microclima , Cidades , Ecossistema , Temperatura Alta , Qualidade de Vida
2.
Oecologia ; 198(3): 825-834, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35246751

RESUMO

Microclimate is a crucial driver of saproxylic beetle assemblages, with more species often found in sunny forests than in shady ones. Whether this pattern is caused by a higher detectability due to increased beetle activity under sunny conditions or a greater diversity of beetles emerging from sun-exposed deadwood remains unclear. This study examined whether sun exposure leads to higher microclimatic heterogeneity in deadwood and whether this drives beetle diversity in deadwood logs and at forest stand scale. Saproxylic beetles were sampled at the stand scale using flight-interception traps and at object scale using stem-emergence traps on deadwood logs at the same site. The variability in wood surface temperature was measured on single logs and between logs as a proxy for microclimatic heterogeneity in deadwood. Abundance in sunny forests was higher at the stand scale, and in shady forests at the object scale. The estimated number of species was higher in sunny forests at both scales and correlated positively with temperature variability on single logs and between logs at the stand scale and, albeit weakly, with temperature variability on single logs at the object scale. Gamma-diversity, and thus beta-diversity, across logs at the object scale was higher in sunny forests. These findings indicate that sun exposure promotes saproxylic beetle diversity due to higher microclimatic heterogeneity within and between deadwood logs. Our study therefore corroborates previous research demonstrating the importance of canopy cover and microclimate for forest biodiversity.


Assuntos
Besouros , Animais , Biodiversidade , Florestas , Microclima , Luz Solar , Árvores
3.
Sci Total Environ ; 825: 154009, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35202697

RESUMO

Sun and wind are important physical factors that influence outdoor thermal comfort. This study compared the impact of sun and wind on outdoor thermal sensation by analyzing 3546 samples of subject test data during a case study in a cold climate city Tianjin, China. The data was collected from subject tests conducted under air temperatures ranging from 3.8 °C to 35.2 °C (mean 20.2 °C), wind from 0 to 4.8 m/s (mean 0.6 m/s), mean radiant temperature 1.8 to 68.9 °C (mean 36.8 °C) in Tianjin, China. In this particular study, the sun was found to be a more significant factor than wind during the test. Standardized linear regression of the pooled dataset revealed that the contributions of air temperature, sun, wind, and humidity to thermal sensation were 56%, 29.4%, 8.8%, and 5.9%, respectively. When compared under different air temperature ranges, the effect of sun was more than two times greater that of wind. When the air temperature was in the range of 5-10 °C, solar exposure increased the thermal sensation by more than 2 units, but a reduction in wind speed had no observable effect on thermal sensation. When the air temperature was as high as 30-35 °C, increasing the wind by up to 2 m/s lowered the thermal sensation in the shade, but not in the sun. A summary of pedestrian level wind measured in real urban spaces in 28 previous studies indicated that urban spaces generally have low wind speeds, with the median value of mean wind speed of 0.8 m/s. The results of this study provide useful information for designs to creating comfortable urban open spaces.


Assuntos
Clima Frio , Vento , Cidades , Umidade , Microclima , Temperatura , Sensação Térmica
4.
Nat Commun ; 13(1): 917, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35177619

RESUMO

Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial. Here, we use terrestrial LiDAR surveys every two weeks spanning wet and dry seasons in Central Amazonia to show that plant phenology varies strongly across vertical strata in old-growth forests, but is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we find that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests lost plant material. In contrast, the understory greened up with increased light availability driven by the upper canopy loss, alongside increases in solar radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures in forest edges exacerbated the upper canopy losses of large trees throughout the dry season, whereas the understory in these light-rich environments was less dependent on the altered upper canopy structure. Our findings reveal a strong influence of edge effects on phenological controls in wet forests of Central Amazonia.


Assuntos
Florestas , Folhas de Planta/fisiologia , Árvores/fisiologia , Brasil , Luz , Microclima , Estações do Ano , Solo/química , Água/química
5.
Int J Biometeorol ; 66(4): 817-832, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35113230

RESUMO

Peatlands perform many important ecosystem functions at both the local and global scale, including hydrologic and climatic regulation. Although peatlands often act as climatic microrefugia, they have rarely been the subject of long-term microclimatic studies. In this study, we aimed to compare the local climatic conditions of a mid-forest mire to that of an open area and examine the differences in microclimates within the mire based on plant community diversity, shading, and water table depths. The peatland studied in this work was significantly cooler than the reference site, mainly due to a higher decline in nighttime air temperatures. However, the daily maximum air temperature near the ground was often higher. We also noticed that microclimates significantly differed within the studied peatland. Wet and shaded microsites were cooler than the sites having a lower water level and receiving higher amounts of solar radiation. The results of the study suggest that peatlands have locally cooler climates, and thus can serve as climate change refugia. These findings can help us interpret reconstructed data from the peat archive, and, when combined with experiments, identify tipping points for peatland ecosystems.


Assuntos
Ecossistema , Microclima , Mudança Climática , Europa (Continente) , Florestas , Solo
6.
Glob Chang Biol ; 28(10): 3222-3235, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35226784

RESUMO

A major challenge in climate change biology is to explain why the impacts of climate change vary around the globe. Microclimates could explain some of this variation, but climate change biologists often overlook microclimates because they are difficult to map. Here, we map microclimates in a freshwater rock pool ecosystem and evaluate how accounting for microclimates alters predictions of climate change impacts on aquatic invertebrates. We demonstrate that average maximum temperature during the growing season can differ by 9.9-11.6°C among microclimates less than a meter apart and this microclimate variation might increase by 21% in the future if deeper pools warm less than shallower pools. Accounting for this microclimate variation significantly alters predictions of climate change impacts on aquatic invertebrates. Predictions that exclude microclimates predict low future occupancy (0.08-0.32) and persistence probabilities (2%-73%) for cold-adapted taxa, and therefore predict decreases in gamma richness and a substantial shift toward warm-adapted taxa in local communities (i.e., thermophilization). However, predictions incorporating microclimates suggest cool locations will remain suitable for cold-adapted taxa in the future, no change in gamma richness, and 825% less thermophilization. Our models also suggest that cool locations will become suitable for warm-adapted taxa and will therefore accumulate biodiversity in the future, which makes cool locations essential for biodiversity conservation. Simulated protection of the 10 coolest microclimates (9% of locations on the landscape) results in a 100% chance of conserving all focal taxa in the future. In contrast, protecting the 10 currently most biodiverse locations, a commonly employed conservation strategy, results in a 3% chance of conserving all focal taxa in the future. Our study suggests that we must account for microclimates if we hope to understand the future impacts of climate change and design effective conservation strategies to limit biodiversity loss.


Assuntos
Mudança Climática , Ecossistema , Animais , Biodiversidade , Invertebrados , Microclima
7.
J Therm Biol ; 104: 103163, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35180957

RESUMO

The present investigation evaluated the effect of microclimate modification on feed intake, growth performance, and hemato-biochemical profile of Murrah buffalo (Bubalus bubalis) heifers during summer. Twenty-four buffalo heifers, between 15 and 20 months of age with an average body weight of 363.75 ± 11.27 kg, were randomly assigned to 4 groups based on their age and body weight. The heifers of the T0 (control) group were kept under the shed without any cooling treatment, while the animals in group T1 were tied with a cooling jacket. Buffalo heifers of group T2 were subjected to a cooling jacket with forced ventilation and animals in group T3 were treated with intermittent sprinkling (10 min., at 2 h intervals) and forced ventilation between 9.00 AM and 6.00 PM during the experiment. The ambient temperature inside the shed and core body temperature were reduced in groups T1, T2, and T3 compared to T0. Heifers had higher dry matter intake when subjected to cooling treatments T1, T2, and T3, whereas water intake was reduced in T2 and T3 groups. The animals in T2 and T3 groups attained higher average daily weight gain, while the feed conversion was better in the T3 group compared to T0. The hematological measures such as hemoglobin, total erythrocyte count, and total leucocyte count were found higher in T0. The serum glucose, sodium, and potassium levels increasedand alkaline phosphatase activity decreased in groups T1, T2 and T3 when compared with T0. It can be concluded that the provision of intermittent sprinkling and cooling jacket in combination with forced ventilation could improve the microclimate, which in turn could enhance the performance of Murrah heifers during hot summer days in the tropics.


Assuntos
Búfalos/fisiologia , Temperatura Baixa , Microclima , Ar Condicionado , Animais , Búfalos/crescimento & desenvolvimento , Ingestão de Alimentos , Feminino , Roupa de Proteção , Estações do Ano , Temperatura Cutânea , Ganho de Peso
8.
Philos Trans R Soc Lond B Biol Sci ; 377(1846): 20210004, 2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35067088

RESUMO

Understanding how environmental factors affect the thermal tolerance of species is crucial for predicting the impact of thermal stress on species abundance and distribution. To date, species' responses to thermal stress are typically assessed on laboratory-reared individuals and using coarse, low-resolution, climate data that may not reflect microhabitat dynamics at a relevant scale. Here, we examine the daily temporal variation in heat tolerance in a range of species in their natural environments across temperate and tropical Australia. Individuals were collected in their habitats throughout the day and tested for heat tolerance immediately thereafter, while local microclimates were recorded at the collection sites. We found high levels of plasticity in heat tolerance across all the tested species. Both short- and long-term variability of temperature and humidity affected plastic adjustments of heat tolerance within and across days, but with species differences. Our results reveal that plastic changes in heat tolerance occur rapidly at a daily scale and that environmental factors on a relatively short timescale are important drivers of the observed variation in thermal tolerance. Ignoring such fine-scale physiological processes in distribution models might obscure conclusions about species' range shifts with global climate change. This article is part of the theme issue 'Species' ranges in the face of changing environments (part 1)'.


Assuntos
Evolução Biológica , Mudança Climática , Ecossistema , Humanos , Microclima , Plásticos , Temperatura
9.
Ecology ; 103(4): e3645, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35072948

RESUMO

Insectivores of the tropical rainforest floor are consistently among the most vulnerable birds to forest clearing and fragmentation. Several hypotheses attempt to explain this pattern, including sensitivity to extreme microclimates found near forest borders, particularly brighter and warmer conditions. Importantly, this "microclimate hypothesis" has additional implications for intact forest under global climate change that could be evaluated through direct assessment of the light and temperature environment of terrestrial insectivores. In this study, we harness novel technology to directly quantify the light and thermal niches of 10 species of terrestrial insectivores in undisturbed Amazonian rainforest. Loggers placed on birds (N = 33) and their environment (N = 9) recorded nearly continuous microclimate data from 2017 to 2019, amassing >5 million measurements. We found that midday light intensity in tree fall gaps (~39,000 lux) was >40 times higher than at the ground level of forest interior (950 lux). Light intensity registered by sensors placed on birds averaged 17.4 (range 3.9-41.5) lux, with species using only 4.3% (0.9%-10.4%) of available light on the forest floor. Birds therefore selected very dark microhabitats-the light environment was >2200 times brighter in tree fall gaps. Bird thermal niche was a function of ambient temperature as well as body temperature, which averaged >40.5°C but varied among species. Forest floor temperature peaked daily at 27.0°C, whereas bird loggers averaged 35.1°C (34.5-35.7°C) at midday. The antpitta Myrmothera campanisona and the antthrush Formicarius colma used thermal conditions closest to their body temperatures, whereas leaftossers (Sclerurus spp.) and Myrmornis torquata occupied relatively cool microclimates. We found no general link between abundance trends and variation in species-specific light and thermal niches. However, all species occupied markedly dim and cool microclimates. Because such conditions are rare outside the interior of primary forest, these results support the microclimate hypothesis in disturbed landscapes. Moreover, strong avoidance of conditions that are becoming more common under climate change highlights the vulnerability of terrestrial insectivores even in the absence of disturbance and may be the reason for enigmatic declines in Amazonia and elsewhere.


Assuntos
Aves , Floresta Úmida , Animais , Ecossistema , Florestas , Microclima , Árvores
10.
Int J Biometeorol ; 66(4): 719-730, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35059817

RESUMO

Field experiments were conducted at Biswanath, Assam, India (26° 42' N and 93° 15' E), during 2016, 2017, and 2018, to evaluate the effect of microclimates on growth, yield, and disease incidence in the ginger crop. The ginger variety Nadia was grown under six microclimates, viz., under shade net for the entire crop season (T1), under shade net from planting to mid-October (T2), with pigeon pea (T3), with maize (T4), with okra (T5), and as a sole crop (T6) in three replicated RBD. Photosynthetically active radiation (PAR), net radiation (Rn), temperature above the ginger canopy, soil temperature, and soil moisture were measured during the critical crop growth period under different microclimates. Recording of rhizome rot disease incidence was done periodically and genomic analysis of pathogen was carried out. PAR recorded above the ginger canopy under T6 was 1688.1 µ mol s-1 m-2, which was attenuated up to 80.1% in other microclimates. The Rn load of the ginger canopy was maximum (446.4 W m-2) under T6, which reduced to below 50 W m-2 under both T3 and T4. Both air temperatures above the ginger canopy and soil temperatures under T3 and T4 were reduced by 3.3 °C and 4.6 °C, respectively, as compared to T6. The pathogen causing the disease in the experimental site was identified as Fusarium oxysporum. Considerable increase in soil and air temperature and soil moisture favored disease incidence (90.3%) under shade net (T1 and T2) treatments, while opposite reason causing significant reduction in disease incidence (16.1%) was observed under T3 and T4. More yield of ginger recorded in treatments T3 (6.21 t ha-1) or T4 (6.48 t ha-1) was attributed to better crop growth and diminutive disease incidence, while the crop was almost damaged due to severe disease incidence under shade net (T1 and T2) treatments.


Assuntos
Gengibre , Gengibre/genética , Incidência , Microclima , Rizoma , Solo
11.
Sensors (Basel) ; 22(2)2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35062468

RESUMO

The rapid urbanization process brings consequences to urban environments, such poor air quality and the urban heat island issues. Due to these effects, environmental monitoring is gaining attention with the aim of identifying local risks and improving cities' liveability and resilience. However, these environments are very heterogeneous, and high-spatial-resolution data are needed to identify the intra-urban variations of physical parameters. Recently, wearable sensing techniques have been used to perform microscale monitoring, but they usually focus on one environmental physics domain. This paper presents a new wearable system developed to monitor key multidomain parameters related to the air quality, thermal, and visual domains, on a hyperlocal scale from a pedestrian's perspective. The system consisted of a set of sensors connected to a control unit settled on a backpack and could be connected via Wi-Fi to any portable equipment. The device was prototyped to guarantee the easy sensors maintenance, and a user-friendly dashboard facilitated a real-time monitoring overview. Several tests were conducted to confirm the reliability of the sensors. The new device will allow comprehensive environmental monitoring and multidomain comfort investigations to be carried out, which can support urban planners to face the negative effects of urbanization and to crowd data sourcing in smart cities.


Assuntos
Microclima , Dispositivos Eletrônicos Vestíveis , Cidades , Monitoramento Ambiental , Temperatura Alta , Reprodutibilidade dos Testes
12.
Sensors (Basel) ; 22(2)2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35062573

RESUMO

The environmental microclimatic characteristics are often subject to fluctuations of considerable importance, which can cause irreparable damage to art works. We explored the applicability of Artificial Intelligence (AI) techniques to the Cultural Heritage area, with the aim of predicting short-term microclimatic values based on data collected at Rosenborg Castle (Copenhagen), housing the Royal Danish Collection. Specifically, this study applied the NAR (Nonlinear Autoregressive) and NARX (Nonlinear Autoregressive with Exogenous) models to the Rosenborg microclimate time series. Even if the two models were applied to small datasets, they have shown a good adaptive capacity predicting short-time future values. This work explores the use of AI in very short forecasting of microclimate variables in museums as a potential tool for decision-support systems to limit the climate-induced damages of artworks within the scope of their preventive conservation. The proposed model could be a useful support tool for the management of the museums.


Assuntos
Inteligência Artificial , Museus , Previsões , Microclima , Redes Neurais de Computação , Temperatura
13.
Sensors (Basel) ; 22(2)2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35062580

RESUMO

Satisfactory indoor thermal environments can improve working efficiencies of office staff. To build such satisfactory indoor microclimates, individual thermal comfort assessment is important, for which personal clothing insulation rate (Icl) and metabolic rate (M) need to be estimated dynamically. Therefore, this paper proposes a vision-based method. Specifically, a human tracking-by-detection framework is implemented to acquire each person's clothing status (short-sleeved, long-sleeved), key posture (sitting, standing), and bounding box information simultaneously. The clothing status together with a key body points detector locate the person's skin region and clothes region, allowing the measurement of skin temperature (Ts) and clothes temperature (Tc), and realizing the calculation of Icl from Ts and Tc. The key posture and the bounding box change across time can category the person's activity intensity into a corresponding level, from which the M value is estimated. Moreover, we have collected a multi-person thermal dataset to evaluate the method. The tracking-by-detection framework achieves a mAP50 (Mean Average Precision) rate of 89.1% and a MOTA (Multiple Object Tracking Accuracy) rate of 99.5%. The Icl estimation module gets an accuracy of 96.2% in locating skin and clothes. The M estimation module obtains a classification rate of 95.6% in categorizing activity level. All of these prove the usefulness of the proposed method in a multi-person scenario of real-life applications.


Assuntos
Regulação da Temperatura Corporal , Temperatura Cutânea , Vestuário , Humanos , Microclima , Temperatura
14.
Sci Rep ; 12(1): 971, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-35046462

RESUMO

Disease results from interactions among the host, pathogen, and environment. Inoculation trials can quantify interactions among these players and explain aspects of disease ecology to inform management in variable and dynamic natural environments. White-nose Syndrome, a disease caused by the fungal pathogen, Pseudogymnoascus destructans (Pd), has caused severe population declines of several bat species in North America. We conducted the first experimental infection trial on the tri-colored bat, Perimyotis subflavus, to test the effect of temperature and humidity on disease severity. We also tested the effects of temperature and humidity on fungal growth and persistence on substrates. Unexpectedly, only 37% (35/95) of bats experimentally inoculated with Pd at the start of the experiment showed any infection response or disease symptoms after 83 days of captive hibernation. There was no evidence that temperature or humidity influenced infection response. Temperature had a strong effect on fungal growth on media plates, but the influence of humidity was more variable and uncertain. Designing laboratory studies to maximize research outcomes would be beneficial given the high costs of such efforts and potential for unexpected outcomes. Understanding the influence of microclimates on host-pathogen interactions remains an important consideration for managing wildlife diseases, particularly in variable environments.


Assuntos
Ascomicetos/fisiologia , Quirópteros/microbiologia , Interações Hospedeiro-Parasita , Microclima , Animais , Composição Corporal , Quirópteros/metabolismo , Feminino , Hibernação , Umidade , Hidrocortisona/metabolismo , Masculino , Temperatura
15.
Int J Biometeorol ; 66(3): 449-456, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35064319

RESUMO

The objective was to evaluate the microclimate and animal thermal comfort indexes in silvopastoral system in the Brazilian semiarid region with different woody cover levels within Caatinga trees. The experiment was carried out at the Teaching, Research and Extension Unit of the Federal Institute of Science and Technology of Ceará, Campus Limoeiro do Norte, in Chapada do Apodi, CE, in 2018. The treatments were forage grown under woody cover of 46.15% (SS46), forage grown under woody cover of 30.00% (SS30), and forage grown under woody cover of 17.64% (SS18). The evaluations were carried out during three consecutive days, in the vegetative, transition, and dormancy periods at 6 a.m.; 10 a.m.; 2 p.m. and 6 p.m.. First, the microclimate variables, relative air humidity (%), wind speed (m s-1), dry bulb temperature (°C), wet bulb temperature (°C), black globe temperature (°C), and dew point temperature (°C), were obtained for subsequent calculation of black globe temperature and humidity index and radiant thermal load (W m-2). SS46, SS30, and SS18 systems had no differences of black globe temperature and humidity index and radiant thermal load in the sun. There were significant reductions in black globe temperature and humidity index and radiant thermal load within the trees promoting improvement in the thermal environment at times of higher radiation load. The trees promoted better conditions of animal thermal comfort in all silvopastoral arrangements and periods of the year.


Assuntos
Microclima , Árvores , Animais , Umidade , Temperatura , Vento
16.
Sci Total Environ ; 821: 153377, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35077798

RESUMO

Increasingly available high-resolution digital elevation models (DEMs) facilitate the use of fine-scale topographic variables as proxies for microclimatic effects not captured by the coarse-grained macroclimate datasets. Species distributions and community assembly rules are, however directly shaped by microclimate and not by topography. DEM-derived topography, sometimes combined with vegetation structure, is thus widely used as a proxy for microclimatic effects in ecological research and conservation applications. However, the suitability of such a strategy has not been evaluated against in situ measured microclimate and species composition. Because bryophytes are highly sensitive to microclimate, they are ideal model organisms for such evaluation. To provide this much needed evaluation, we simultaneously recorded bryophyte species composition, microclimate, and forest vegetation structure at 218 sampling sites distributed across topographically complex sandstone landscape. Using a LiDAR-based DEM with a 1 m resolution, we calculated eleven topographic variables serving as a topographic proxy for microclimate. To characterize vegetation structure, we used hemispherical photographs and LiDAR canopy height models. Finally, we calculated eleven microclimatic variables from a continuous two-year time- series of air and soil temperature and soil moisture. To evaluate topography and vegetation structure as substitutes for the ecological effect of measured microclimate, we partitioned the variation in bryophyte species composition and richness explained by microclimate, topography, and vegetation structure. In situ measured microclimate was clearly the most important driver of bryophyte assemblages in temperate coniferous forests. The most bryophyte-relevant variables were growing degree days, maximum air temperature, and mean soil moisture. Our results thus showed that topographic variables, even when derived from high-resolution LiDAR data and combined with in situ sampled vegetation structure, cannot fully substitute effects of in situ measured microclimate on forest bryophytes.


Assuntos
Briófitas , Microclima , Florestas , Solo , Temperatura , Árvores
17.
Int J Biometeorol ; 66(3): 535-544, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34716805

RESUMO

This work aimed to evaluate the thermal comfort provided by shading structures in free-range systems under a tropical environment, based on microclimate variables of nets with different materials. During the experiment, the unshading area; the natural shading of a native tree species to the Brazilian Savanna; and the artificial 80% shadings nets: black polypropylene, heat-reflective aluminized, and association of both were evaluated. The shading structures were analyzed in paddocks at the Água Limpa Farm from the University of Brasília, where dry-bulb, wet-bulb, black globe temperatures, and wind speed were collected for the micrometeorological characterization from 8:00 am to 4:00 pm. From the temperatures, the vapor pressures and the humidities were calculated. The shortwave radiation was calculated through the sum of direct, diffuse, and reflected radiations. The mean radiant temperature, radiant heat load, and black globe temperature and humidity index were calculated. The internal and external surface temperatures of the nets and the soil temperature were measured every 30 min. The data were analyzed with aid of the statistical analysis system. The air temperature varied according to the shortwave radiation, from 25.6 °C at 8:00 am to 29.6 °C at 1:00 pm, with a decrease over the hours. Despite the air temperature of the trees showed the lowest average, the nets association structure was the most reduced all the thermal comfort indexes. The heat-reflective net presented the lowest soil temperature at all hours (under 26.1 °C). In general, the shadings proved to be efficient in promoting thermal comfort in free-range systems.


Assuntos
Pradaria , Microclima , Umidade , Temperatura , Árvores
18.
Sci Total Environ ; 808: 152143, 2022 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-34871685

RESUMO

Cities have faced rapid urbanization, which has changed the impact of the micro-thermal environment on residents' thermal comfort level. Therefore, planners need to understand the city's physical environment so they can identify and ameliorate the effects of the changing in micro-thermal environment. Researchers also need to identify and understand pedestrians' thermal comfort level in street canyons to determine which urban physical factors planners need to improve. This study aimed to observe how thermal comfort affects pedestrian behavior in micro-thermal environments and to determine which urban geometry factors influence pedestrians' thermal comfort. This study collected data in downtown Austin, TX using a mobile weather station, and analyzed the microclimate conditions experienced by pedestrians. A camera mounted on the weather station also allowed us to observe pedestrian behavior patterns. The results revealed that pedestrians tended to choose walking, sitting, and standing locations with high thermal comfort levels such as in the shade on the sidewalk. There was also some correlation between thermal comfort levels and pedestrian behavior patterns. The sky view factor (SVF) and tree canopy coverage ratio (TCR) were also correlated with pedestrians' thermal comfort. This study highlights the need for future research to develop a data collection method for efficient microscopic thermal environment research and a thermal environment estimation and analysis approach from a three-dimensional perspective.


Assuntos
Pedestres , Cidades , Humanos , Microclima , Sensação Térmica , Caminhada , Tempo (Meteorologia)
19.
Sci Total Environ ; 808: 152005, 2022 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-34871696

RESUMO

An inverted U-shape relationship between cognitive performance and indoor temperature with best performance peaking at 21.6 °C was previously described. Little is known on classroom temperature reduction effects on cognitive performances and cardiac autonomic profile, during the cold season. Fifteen students underwent electrocardiogram recording during a lecture in two days in December when classroom temperatures were set as neutral (NEUTRAL, 20-22 °C) and cool (COOL, 16-18 °C). Cognitive performance (memory, verbal ability, reasoning, overall cognitive C-score) was assessed by Cambridge Brain Science cognitive evaluation tool. Cardiac autonomic control was evaluated via the analysis of spontaneous fluctuations of heart period, as the temporal distance between two successive R-wave peaks (RR). Spectral analysis provided the power in the high frequency (HF, 0.15-0.40 Hz) and low frequency (LF, 0.04-0.15 Hz) bands of RR variability. Sympatho-vagal interaction was assessed by LF to HF ratio (LF/HF). Symbolic analysis provided the fraction of RR patterns composed by three heart periods with no variation (0 V%) and two variations (2 V%), taken as markers of cardiac sympathetic and vagal modulations, respectively. The students' thermal comfort was assessed during NEUTRAL and COOL trials. Classroom temperatures were 21.5 ± 0.8 °C and 18.4 ± 0.4 °C during NEUTRAL and COOL. Memory, verbal ability, C-Score were greater during COOL (13.01 ± 3.43, 12.32 ± 2.58, 14.29 ± 2.90) compared to NEUTRAL (9.98 ± 2.26, p = 0.002; 8.57 ± 1.07, p = 0.001 and 10.35 ± 3.20, p = 0.001). LF/HF (2.4 ± 1.7) and 0 V% (23.2 ± 11.1%) were lower during COOL compared to NEUTRAL (3.7 ± 2.8, p = 0.042; 28.1 ± 12.2.1%, p = 0.031). During COOL, 2 V% was greater (30.5 ± 10.9%) compared to NEUTRAL (26.2 ± 11.3, p = 0.047). The students' thermal comfort was slightly reduced during COOL compared to NEUTRAL trial. During cold season, a better cognitive performance was obtained in a cooler indoor setting enabling therefore energy saving too.


Assuntos
Sistema Nervoso Autônomo , Microclima , Cognição , Frequência Cardíaca , Humanos , Estudantes
20.
Environ Sci Pollut Res Int ; 29(14): 20892-20905, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34743307

RESUMO

Changes in land-use/land-cover (LULC) give rise to several environmental problems which modify the microclimate of a region. Therefore, land surface temperature (LST) is a significant environmental variable that is appreciably influenced by LULC changes. The main aim of this research was to quantify the impacts of LULC changes from the drying of Toshka Lakes on LST by remote sensing and geographic information system (GIS) techniques. Landsat series Thematic Mapper (TM) and Operational Land Imager (OLI) satellite images were used to estimate LST from 2001 to 2019. Automated Water Extraction Index (AWEI) was applied to the mosaicked Landsat images to extract water bodies from the research area. Optimized Soil-Adjusted Vegetation Index (OSAVI) was utilized to predict the reclaimed land in the Toshka region until 2019. The kappa coefficient had been involved in this research to assess the accuracy of water extraction. The results indicated a decrease in the lakes by about 1517.79 km2 with an average increase in LST by about 25.02 °C from 2001 to 2019. It was observed that the dried areas of the lakes were converted to bare soil and are covered by salt crusts. The results indicated that the land-use change was a significant driver for the increased LST. The mean annual LST increased considerably by 0.6 °C/year from 2009 to 2019. A strong negative correlation between LST and Toshka Lakes area (R-square = 0.98) estimated from regression analysis implied that Toshka Lakes drying considerably affected the microclimate of the study area. Severe drought conditions, soil degradation, and many environmental issues were predicted due to the rise of LST in the research area. The findings of this research focus on the benefits of satellite data for assessing human-induced changes and their impacts on microclimate. There is an urgent need to develop favorable strategies for sustainable environmental management in the Toshka region.


Assuntos
Lagos , Microclima , Egito , Monitoramento Ambiental/métodos , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...