scholarly journals Urban Cold and Heat Island in the City of Bragança (Portugal)

Climate ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 70 ◽  
Author(s):  
Artur Gonçalves ◽  
Gabriella Ornellas ◽  
António Castro Ribeiro ◽  
Filipe Maia ◽  
Alfredo Rocha ◽  
...  
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Thermal Environment ◽  
Urban Climate ◽  
Heat Island ◽  
Local Climate ◽  
Climate Conditions ◽  
Urban Green Spaces ◽  
Local Climate Zones ◽  
The City

The thermal environment is an important aspect of the urban environment because it affects the quality of life of urban residents and the energy use in buildings. Urban Heat Island (UHI) and Urban Cold Island (UCI) are complementary effects that are the consequence of cities’ structures interference with the local climate. This article presents results from five years of urban climate monitoring (2012–2016) in a small Portuguese city (Bragança) using a dense meteorological network of 23 locations covering a wide array of Local Climate Zones (LCZ), from urban areas to nearby rural areas. Results show the presence of both the UHI effect, from mid-afternoon until sunrise, and the UCI after sunrise, both being more intense under the dense midrise urban context and during the summer. Urban Green Spaces had an impact on both UHI and UCI, with an important role in cooling areas of the city during daytime in the summer. Other LCZs had less impact on local thermal conditions. Despite the small size of this city, both effects (UHI and UCI) had a relevant intensity with an impact on local climate conditions. Both effects tend to decrease in intensity with increasing wind speed and precipitation.

Human thermal comfort in Local climate zones of Berlin

2020 ◽  
Author(s):  
Ines Langer ◽  
Alexander Pasternack ◽  
Uwe Ulbrich
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Heat Island ◽  
Climate Zones ◽  
Local Climate ◽  
Human Thermal Comfort ◽  
Local Climate Zones ◽  
Urban Heat ◽  
The City

<p>Urban areas show higher nocturnal temperature comparing to rural areas, which is denoted by urban heat island. This effect can intensify the impact of global warming in urban areas especially during heat waves, that leads to higher energy demand for cooling the building and higher thermal stress for residents.  </p><p>The aim of this study is to identify the Urban Heat Island (UHI) effect during the heat spell 2018 and 2019 in order to calculated human thermal comfort for Berlin. Berlin, the capital city of Germany covers an area of 892km<sup>2</sup> and its population is growing, therefore more residential areas will be planned in future through higher building. The methodology of this research is to divide Berlin into Local Climate Zones (LCZ's) regarding the concept of Stewart & Oke (2012). Then to evaluate the accuracy of this concept using 30 microclimate stations. Estimating the magnitude of urban heat island and its seasonal changes in combination with human thermal perception in different LCZ during summer time is another objective of this research. </p><p>Ten LCZ's for Berlin were selected, as class 1 (compact high rise), class 3 (compact low rise), class 7 (lightweight low-rise), class C (bush, scrub), class E (bare rock or paved) and class F (bare soil or sand) don't exist in Berlin. Class A (dense trees) is with a fraction of 18.6% in a good agreement with the percentage of dense trees reported from the city administration of Berlin (18.4%), class G (water) has a coverage of 5.1% through our classification instead of 6.7% reported by the city administration. In summary, the LCZ 1-10 cover 59.3% (more than half) of the city area.</p><p>Regarding temperature measurements, which represent a hot summer day with calm wind and clear sky the difference of Local Climate Zones will be calculated and the temperature variability in every LCZ's regarding sky view factor values show the hot spot of the city.</p><p>The vulnerability of LCZ's to heat stress will be ranked and discussed regarding ventilation and other factors.</p><p> </p><p>Literature</p><p>Matzarakis, A. Mayer, H., Iziomon, M. (1999) Applications of a universal thermal index: Physiological equivalent temperature: Intern. J. of Biomet 43 (2), 76-84.</p><p>Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.</p><p> </p>

scholarly journals How urbanisation alters the intensity of the urban heat island in a tropical African city

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254371
Author(s):  
Xueqin Li ◽  
Lindsay C. Stringer ◽  
Sarah Chapman ◽  
Martin Dallimer
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Heat Island ◽  
African City ◽  
Local Climate ◽  
Urban Cluster ◽  
Urban Heat ◽  
Management Institutions ◽  
The City

Due to the combined effects of urban growth and climate change, rapid urbanisation is particularly challenging in African cities. Areas that will house a large proportion of the urban population in the future coincide with where natural hazards are expected to occur, and where hazard risk management institutions, knowledge, and capacity are often lacking. One of the challenges posed by rapid urbanisation is the Urban Heat Island (UHI) effect, whereby urban areas are warmer than the surrounding rural areas. This study investigates urbanisation patterns and alterations in surface UHI (SUHI) intensity for the Kampala urban cluster, Uganda. Analyses show that between 1995 and 2017, Kampala underwent extensive changes to its urban built-up area. From the centre of the city to adjoining non-built up areas in all directions, the urban land cover increased from 12,133 ha in 1995 to 25,389 ha in 2016. The area of SUHI intensity in Kampala expanded significantly over the 15-year period of study, expanding from 22,910 ha in 2003 to 27,900 ha in 2016, while the annual daytime SUHI of 2.2°C in 2003 had decreased to 1.9°C by 2017. Although SUHI intensity decreased in some parts of the city, elsewhere it increased, suggesting that urbanisation does not always lead to a deterioration of environmental conditions. We postulate that urban development may therefore not necessarily create an undesirable impact on local climate if it is properly managed. Rapidly growing cities in Africa and elsewhere should ensure that the dynamics of their development are directed towards mitigating potentially harmful environmental impacts, such as UHI effect through careful planning that considers both bluespaces and greenspaces.

scholarly journals Urban heat island modelling based on MUKLIMO: examples from Slovakia

2021 ◽  
Vol 2 ◽  
pp. 1-11
Author(s):  
Monika Kopecká ◽  
Daniel Szatmári ◽  
Juraj Holec ◽  
Ján Feranec
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Heat Island ◽  
Local Climate ◽  
Mountain Ranges ◽  
Spatially Correlated ◽  
Local Climate Zones ◽  
Urban Heat ◽  
Summer Time ◽  
The City

Abstract. Cities are generally expected to experience higher temperatures than surrounding rural areas due to the Urban Heat Island (UHI) effect. The aim of this paper is to document identification and delimitation of land cover/land use (LC/LU) classes based on Urban Atlas data in three cities in Slovakia: the capital Bratislava and two regional centres, Trnava and Žilina, in the years 1998–2016 and their effect on the temperature change. The concept of Local Climate Zones (replaced by LC/LU classes in this study) was used as an input for the UHI modelling by application of the Mikroskaliges Urbanes KLIma MOdell (MUKLIMO). The model MUKLIMO was validated by data taken in five stations in Bratislava, two in Trnava, and one in Žilina, while a good rate of agreement between the modelled and measured data was statistically proved. A single representative day (August 22, 2018) was chosen for which UHI was modelled with three inputs of LC/LU classes: situation in 1998, 2007, and 2016 to assess the effect of change of LC/LU classes on the distribution of temperatures. The spatial manifestation of UHI was assessed in the frame of LC/LU classes for 2016 at 21:00 of Central European Summer Time (CEST). The results indicate that UHI intensity trends are spatially correlated with LC/LU classes and their change pattern. Results of Bratislava show, regarding the size of the city and relief dissection, greater variability than smaller Trnava situated in flat terrain and Žilina situated in the river valley surrounded by the mountain ranges.

scholarly journals Periurbanization and conservation pressures over remnants of native vegetation: impact on ecosystem services for a Latin-American capital city

2019 ◽  
Vol 4 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Francisco de la Barrera ◽  
Cristián Henríquez ◽  
Fanny Coulombié ◽  
Cynnamon Dobbs ◽  
Alejando Salazar
Keyword(s):  
Ecosystem Services ◽  
Latin American ◽  
Urban Areas ◽  
Urban Expansion ◽  
Capital City ◽  
Local Climate ◽  
Urban Green Spaces ◽  
Vegetation Impact ◽  
Development Alternatives ◽  
The City

Abstract Urban expansion in Latin-American cities is faster than urban planning. In order to implement sustainable planning the capacity of peri-urban areas to provide ecosystem services must be evaluated in the context of competing urbanization and conservation pressures. In this study we analyzed the effect of urban expansion on peri-urban vegetation of the Metropolitan Area of Santiago and what ecosystem services are provided by El Panul, land rich in biodiversity embedded in the fringe of the city. The city has lost vegetation while urbanized areas grow. Under this context, we evaluated the multi-functionality of El Panul through the quantification of three ecosystem services (ES): sense of place through the interviews of 60 residents, recreation via GIS analyses, and local climate regulation determined with air temperature measurements. El Panul increased the provision of urban green spaces, where inhabitants recognize and appreciate ES, and it plays a significant role in mitigating the urban heat island on summer nights. ES have emerged as a concept and framework for evaluating competing urban development alternatives.

Climate Bubbles: Games to Monitor Urban Climate

Leonardo ◽  
2011 ◽  
Vol 44 (1) ◽  
pp. 64-65
Author(s):  
Drew Hemment ◽  
Carlo Buontempo ◽  
Alfie Dennen
Keyword(s):  
Urban Heat Island ◽  
Air Flow ◽  
Urban Climate ◽  
Heat Island ◽  
Local Climate ◽  
Flow Circulation ◽  
Urban Heat ◽  
The City

Climate Bubbles was a playful, participatory mass observation project on local climate. Bubble blowing games were devised to enable people across the city of Manchester to test air flow circulation and, by sharing the results online, enabled the Met Office to create a snapshot of the effect the Urban Heat Island has on wind.

scholarly journals Impact of Urban Canopy Parameters on a Megacity’s Modelled Thermal Environment

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1349
Author(s):  
Mikhail Varentsov ◽  
Timofey Samsonov ◽  
Matthias Demuzere
Keyword(s):  
Urban Areas ◽  
Climate Model ◽  
Thermal Environment ◽  
Weather Prediction ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Climate Modelling ◽  
Local Climate ◽  
Anthropogenic Heat Flux ◽  
Local Climate Zones

Urban canopy parameters (UCPs) are essential in order to accurately model the complex interplay between urban areas and their environment. This study compares three different approaches to define the UCPs for Moscow (Russia), using the COSMO numerical weather prediction and climate model coupled to TERRA_URB urban parameterization. In addition to the default urban description based on the global datasets and hard-coded constants (1), we present a protocol to define the required UCPs based on Local Climate Zones (LCZs) (2) and further compare it with a reference UCP dataset, assembled from OpenStreetMap data, recent global land cover data and other satellite imagery (3). The test simulations are conducted for contrasting summer and winter conditions and are evaluated against a dense network of in-situ observations. For the summer period, advanced approaches (2) and (3) show almost similar performance and provide noticeable improvements with respect to default urban description (1). Additional improvements are obtained when using spatially varying urban thermal parameters instead of the hard-coded constants. The LCZ-based approach worsens model performance for winter however, due to the underestimation of the anthropogenic heat flux (AHF). These results confirm the potential of LCZs in providing internationally consistent urban data for weather and climate modelling applications, as well as supplementing more comprehensive approaches. Yet our results also underline the continued need to improve the description of built-up and impervious areas and the AHF in urban parameterizations.

Comparison of urban climate measurements in Berlin and LES model output for a special observation period

2021 ◽  
Author(s):  
Ines langer ◽  
Alexander Pasternack ◽  
Uwe Ulbrich ◽  
Henning Rust
Keyword(s):  
Mean Square Error ◽  
Urban Climate ◽  
Specific Humidity ◽  
Mean Square ◽  
Climate Zones ◽  
Local Climate ◽  
Large Eddy Simulation Model ◽  
Local Climate Zones ◽  
The City ◽  
Observation Period

<p>Surface (2 m) temperature and specific humidity data are measured at 5-minute intervals in a network comprising 33 stations distributed across the city of Berlin, Germany. These data are utilized in order to validate a LES (large eddy simulation) model designed to assess the local climate at a very high resolution of 10 m to 1 m. This model, was developed at the ​Institute of Meteorology and Climatology (IMUK) of the Leibniz Universität Hannover, Germany, and is developed into an application tool for city planners within the funding programme "[UC²] - Urban Climate under Change", of the German Federal Ministry of Education and Research (BMBF).</p><p>The evaluation distinguishes between the different Local climate zones (LCZ) in the city, which are defined following the concept of Stewart & Oke (2012). For Berlin, the following LCZ have been identified: 2 (compact midrise), 4 (open high-rise), 6 (open low-rise), 8 (large low-rise), A (dense trees), B (scattered trees), D (low Plants), G (water).</p><p>We analyzed one cold winter day during an intensive observation period from 06 UTC on 17<sup>th</sup> January to 06 UTC on 18<sup>th</sup> January, 2017. The minimum and maximum recorded temperatures were -8.1 °C and +2 °C, respectively, the sun shine duration was 6.5 hours. Daily and hourly mean absolute error, mean square error and root mean square error confirm that the deviation between measurements and the PALM-4U model differs between the LCZ for Berlin, with particularly large negative deviations of up to 5 K in forest areas, as they are not yet well represented in the model. Smallest deviations are found for the industrial zone. In all cases, the observed amplitude of the diurnal cycle is underestimated. The role of the driving model for the deviations found is addressed.</p><p>Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.</p><p> </p>

scholarly journals Mapping Local Climate Zones and Their Applications in European Urban Environments: A Systematic Literature Review and Future Development Trends

2021 ◽  
Vol 10 (4) ◽  
pp. 260
Author(s):  
Michal Lehnert ◽  
Stevan Savić ◽  
Dragan Milošević ◽  
Jelena Dunjić ◽  
Jan Geletič
Keyword(s):  
Urban Areas ◽  
Urban Climate ◽  
Well Being ◽  
Climatic Conditions ◽  
Urban Environments ◽  
Outdoor Thermal Comfort ◽  
Climate Zones ◽  
Local Climate ◽  
Local Climate Zones ◽  
Scale Modelling

In the light of climate change and burgeoning urbanization, heat loads in urban areas have emerged as serious issues, affecting the well-being of the population and the environment. In response to a pressing need for more standardised and communicable research into urban climate, the concept of local climate zones (LCZs) has been created. This concept aims to define the morphological types of (urban) surface with respect to the formation of local climatic conditions, largely thermal. This systematic review paper analyses studies that have applied the concept of LCZs to European urban areas. The methodology utilized pre-determined keywords and five steps of literature selection. A total of 91 studies were found eligible for analysis. The results show that the concept of LCZs has been increasingly employed and become well established in European urban climate research. Dozens of measurements, satellite observations, and modelling outcomes have demonstrated the characteristic thermal responses of LCZs in European cities. However, a substantial number of the studies have concentrated on the methodological development of the classification process, generating a degree of inconsistency in the delineation of LCZs. Recent trends indicate an increasing prevalence of the accessible remote-sensing based approach over accurate GIS-based methods in the delineation of LCZs. In this context, applications of the concept in fine-scale modelling appear limited. Nevertheless, the concept of the LCZ has proven appropriate and valuable to the provision of metadata for urban stations, (surface) urban heat island analysis, and the assessment of outdoor thermal comfort and heat risk. Any further development of LCZ mapping appears to require a standardised objective approach that may be globally applicable.

scholarly journals A new approach for highly resolved air temperature measurements in urban areas

2011 ◽  
Vol 4 (1) ◽  
pp. 1001-1019 ◽  
Author(s):  
M. Buttstädt ◽  
T. Sachsen ◽  
G. Ketzler ◽  
H. Merbitz ◽  
C. Schneider
Keyword(s):  
Air Temperature ◽  
Urban Areas ◽  
Thermal Conditions ◽  
Research Programme ◽  
Temperature Data ◽  
Urban Structure ◽  
New Approach ◽  
Local Climate ◽  
Climate Conditions ◽  
The City

Abstract. In different fields of applied local climate investigation, highly resolved data of air temperature are of great importance. As a part of the research programme entitled City2020+, which deals with future climate conditions in agglomerations, this study focuses on increasing the quantity of urban air temperature data intended for the analysis of their spatial distribution. A new measurement approach using local transport buses as "riding thermometers" is presented. By this means, temperature data with a very high temporal and spatial resolution could be collected during scheduled bus rides. The data obtained provide the basis for the identification of thermally affected areas and for the investigation of factors in urban structure which influence the thermal conditions. Initial results from the ongoing study, which show the temperature distribution along different traverses through the city of Aachen, are presented.

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