The allometric scaling of thermal emissions from temperate and tropical cities

2020 ◽  
Author(s):  
Mukhtar Abdulrasheed
Keyword(s):  
Power Law ◽  
Urban Areas ◽  
Allometric Scaling ◽  
Total Population ◽  
Thermal Emission ◽  
Surprising Result ◽  
Night Time ◽  
Population Total ◽  
Local Climate ◽  
Thermal Emissions

<p><strong>ABSTRACT</strong></p><p>Cities around the world develop energy balances that are different to their surroundings. This study examines the application of allometric scaling to the thermal emission of cities in temperate and tropical regions. Overpasses of UK and Nigeria of the Moderate Resolution Imaging Spectroradiometer (MODIS), covering the period between 2000 and 2017 were sampled to examine the seasonal variability in night-time clear-sky upwelling long-wave energy for selected cities of the two countries. Total (area-integrated) emitted energy was calculated per city and interpreted by looking for ‘allometric’ (power law) scaling against the total population of the urban areas. Both sets of cities produce strong correlations (R<sup>2 </sup>³ 0.8 and R<sup>2</sup>≥0.7) of log (total emission) against log (population). Total night-time emitted energy is found to scale sub-linearly (i.e. with power law index < 1) with population on both countries. However, the slope derived from UK allometry (0.85 ± 0.03) is quite different from that derived for cities in Nigeria (0.4 ± 0.05). When scaled against log (city area), both sets of cities produce linear scalings, demonstrating that the total area of built surface is a more general predictor of thermal emissions than total population, a surprising result given the differences in built form in the two sets of cities. These results are robust to the method chosen to delineate the city boundary. We further investigate the factors underlying these allometric relationships using Local Climate Zone (LCZ) classifications.    </p>

scholarly journals Comparative quantification of local climate regulation by green and blue urban areas in cities across Europe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Romain Goldenberg ◽  
Zahra Kalantari ◽  
Georgia Destouni
Keyword(s):  
Power Law ◽  
Ecosystem Service ◽  
Urban Areas ◽  
Supply And Demand ◽  
Urban Climate ◽  
Urban Ecosystem ◽  
Local Climate ◽  
European Cities ◽  
Climate Regulation ◽  
Regulation Services

AbstractUrban growth alters environmental conditions with major consequences for climate regulation and the exposure of population to heat. Nature-based solutions may be used to alleviate the increasing urban climate pressures, but the climate regulation services that these solutions can supply for and across different urban conditions remains understudied. We comparatively investigate the urban ecosystem service realization (considering the ecosystem service supply and demand spatial interactions) of local climate regulation by vegetated (green) and water-covered (blue) areas across 660 European cities. Results show relatively robust power-law relationships with city population density (average R2 of 0.34) of main indicators of ecosystem service realization. Country-wise fitting for city-average indicators strengthens these relationships, in particular for western European cities (average R2 of 0.66). Cross-city results also show strong power-law relationship of effectiveness in ecosystem service realization with socio-economic measures like Human Development Index and GPD per capita, in particular for the area fraction of city parts with high ecosystem service realization (R2 of 0.77). The quantified relationships are useful for comparative understanding of differences in ecosystem services realization between cities and city parts, and quantitative projection of possible change trends under different types of city growth so that relevant measures can be taken to counteract undesirable trends.

Affective labour and class distinction in the night-time economy

2021 ◽  
pp. 003802612110063
Author(s):  
Steven Threadgold ◽  
David Farrugia ◽  
Julia Coffey
Keyword(s):  
Symbolic Dynamics ◽  
Urban Areas ◽  
Service Work ◽  
Night Time ◽  
Feminist Analysis ◽  
Consumption Experience ◽  
Gendered Politics ◽  
The Aesthetic ◽  
The Relationship ◽  
Class Distinction

This article contributes to recent debates about the relationship between affective labour and class by exploring the classed distinctions enacted through affective labour in the urban night-time economy. Bringing theories of affective labour into a dialogue with Bourdieusian feminist analysis, the article explores the affective and symbolic dynamics of hospitality labour in a gentrified inner-urban neighbourhood of Melbourne, Australia. It shows how the practice of hospitality labour enacts classed distinctions and tensions emerging from the gentrification of inner-urban areas, and how the aesthetic and symbolic dimensions of class contribute to the valorisation of affect in hospitality venues. The valorisation of affect are processes in which the value attributed to an atmosphere or consumption experience is based on the forms of distinction practised within the venue, enacted in aesthetics, tastes and modes of embodiment. The article also shows how practices of class distinction – both ‘punching up’ and ‘managing down’ – are connected to the gendered politics of service work in the way that workers manage the threat of violence or sexual harassment in venues. In general, the article shows how the classed dynamics of gentrification are enacted in affective economies, and therefore how Bourdieusian analysis of class can be usefully deployed in theoretical debates about affective labour.

scholarly journals Validation of the Meteosat storm detection and nowcasting system Cb-TRAM with lightning network data – Europe and South Africa

2013 ◽  
Vol 6 (6) ◽  
pp. 1567-1583 ◽  
Author(s):  
T. Zinner ◽  
C. Forster ◽  
E. de Coning ◽  
H.-D. Betz
Keyword(s):  
South Africa ◽  
South African ◽  
Thermal Emission ◽  
Climatic Conditions ◽  
Probability Of Detection ◽  
Night Time ◽  
Detection Scheme ◽  
Lightning Detection ◽  
Physical Limitations ◽  
Cloud Tops

Abstract. In this paper, recent changes to the Meteosat thunderstorm TRacking And Monitoring algorithm (Cb-TRAM) are presented as well as a validation of Cb-TRAM against data from the European ground-based LIghtning NETwork (LINET) of Nowcast GmbH and the South African Weather Service Lightning Detection Network (SAWS LDN). Validation is conducted along the well-known skill measures probability of detection (POD) and false alarm ratio (FAR) on the basis of Meteosat/SEVIRI pixels as well as on the basis of thunderstorm objects. The values obtained demonstrate specific limitations of Cb-TRAM, as well as limitations of satellite methods in general which are based on thermal emission and solar reflectivity information from thunderstorm cloud tops. Although the climatic conditions and the occurrence of thunderstorms are quite different for Europe and South Africa, quality score values are similar. Our conclusion is that Cb-TRAM provides robust results of well-defined quality for very different climatic regimes. The POD for a thunderstorm with intense lightning is about 80% during the day. The FAR for a Cb-TRAM detection which is not even close to intense lightning is about 50%. If only proximity to any lightning activity is required, FAR is much lower at about 15%. Pixel-based analysis shows that detected thunderstorm object size is not indiscriminately large, but well within physical limitations of the satellite method. Night-time POD and FAR are somewhat worse as the detection scheme does not use the high-resolution visible information during night-time hours. Nowcasting scores show useful values up to approximately 30 min in advance.

Night-time chemistry of biomass burning plumes in urban areas: A dual mobile chamber study

2021 ◽  
Author(s):  
Spiro Jorga ◽  
Kalliopi Florou ◽  
Christos Kaltsonoudis ◽  
John Kodros ◽  
Christina Vasilakopoulou ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Urban Areas ◽  
Mass Spectra ◽  
Prescribed Burning ◽  
Organic Aerosol ◽  
Photochemical Activity ◽  
Organic Nitrate ◽  
Night Time ◽  
Starting Point ◽  
High Concentrations

<p>Biomass burning including residential heating, agricultural fires, prescribed burning, and wildfires is a major source of gaseous and particulate pollutants in the atmosphere. Although, important changes in the size distributions and the chemical composition of the biomass burning aerosol during daytime chemistry have been observed, the corresponding changes at nighttime or in winter where photochemistry is slow, have received relatively little attention. In this study, we tested the hypothesis that nightime chemistry in biomass burning plumes can be rapid in urban areas using a dual smog chamber system.</p><p> </p><p>Ambient urban air during winter nighttime periods with high concentrations of ambient biomass burning organic aerosol is used as the starting point. Ozone was added in the perturbed chamber to simulate mixing with background air (and subsequent NO<sub>3</sub> production and aging) while the second chamber was used as a reference. Following the injection of ozone rapid organic aerosol (OA) formation was observed in all experiments leading to increases of the OA concentration by 20-70%. The oxygen to carbon ratio of the OA increased by 50% on average and the mass spectra of the produced OA was quite similar to that of the oxidized OA mass spectra reported during winter in urban areas. Good correlation was also observed with the produced mass spectra from nocturnal aging of laboratory biomass burning emissions showing the strong contribution of biomass burning emissions in the SOA formation during cold nights with high biomass burning activities. Concentrations of NO<sub>3</sub> radicals as high as 25 ppt were measured in the perturbed chamber with an accompanying production of 0.2-1.2 μg m<sup>-3</sup> of organic nitrate. These results strongly indicate that the OA in biomass burning plumes can evolve rapidly even during wintertime periods with low photochemical activity.</p>

scholarly journals Are pet cats bad for wildlife?

2010 ◽  
Vol 16 (3) ◽  
pp. 155
Author(s):  
Alan Lymbery
Keyword(s):  
Local Government ◽  
Endangered Species ◽  
Urban Areas ◽  
State Governments ◽  
Night Time ◽  
Feral Cats ◽  
Wildlife Populations

Pet cats receive bad press from conservationists. This is partly because there is an obvious link between pet cats and feral cats, and predation by feral cats is widely regarded as a key threatening process for endangered species of small vertebrates in Australia. There is also a perception, however, that pet cats are directly responsible for declines in wildlife populations, particularly around urban areas. As a consequence, many local government authorities have introduced regulations aimed at controlling cats, ranging from night-time curfews and confinement to complete prohibition of cat ownership. Greenaway (2010) discusses the approaches taken by local and state governments to control pet cats throughout Australia.

scholarly journals Supplementary material to "Night-time chemistry of biomass burning emissions in urban areas: A dual mobile chamber study"

2021 ◽  
Author(s):  
Spiro Jorga ◽  
Kalliopi Florou ◽  
Christos Kaltsonoudis ◽  
John Kodros ◽  
Christina Vasilakopoulou ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Urban Areas ◽  
Night Time ◽  
Chamber Study ◽  
Supplementary Material

scholarly journals GIS-based delineation of local climate zones: The case of medium-sized Central European cities

2016 ◽  
Vol 24 (3) ◽  
pp. 2-12 ◽  
Author(s):  
Jan Geletič ◽  
Michal Lehnert
Keyword(s):  
Decision Making ◽  
Urban Areas ◽  
Expert Knowledge ◽  
Mapping Method ◽  
Rural Settlements ◽  
Climate Zones ◽  
Local Climate ◽  
Central European ◽  
European Cities ◽  
Local Climate Zones

Abstract Stewart and Oke (2012) recently proposed the concept of Local Climate Zones (LCZ) to describe the siting of urban meteorological stations and to improve the presentation of results amongst researchers. There is now a concerted effort, however, within the field of urban climate studies to map the LCZs across entire cities, providing a means to compare the internal structure of urban areas in a standardised way and to enable the comparison of cities. We designed a new GIS-based LCZ mapping method for Central European cities and compiled LCZ maps for three selected medium-sized Central European cities: Brno, Hradec Králové, and Olomouc (Czech Republic). The method is based on measurable physical properties and a clearly defined decision-making algorithm. Our analysis shows that the decision-making algorithm for defining the percentage coverage for individual LCZs showed good agreement (in 79–89% of cases) with areas defined on the basis of expert knowledge. When the distribution of LCZs on the basis of our method and the method of Bechtel and Daneke (2012) was compared, the results were broadly similar; however, considerable differences occurred for LCZs 3, 5, 10, D, and E. It seems that Central European cities show a typical spatial pattern of LCZ distribution but that rural settlements in the region also regularly form areas of built-type LCZ classes. The delineation and description of the spatial distribution of LCZs is an important step towards the study of urban climates in a regional setting.

The impact of urban policy scenarios on local climate: a multi-model intercomparison

2021 ◽  
Author(s):  
Arianna Valmassoi ◽  
Jan D. Keller ◽  
Rita Glowienka-Hense
Keyword(s):  
Urban Areas ◽  
Urban Policy ◽  
Western Europe ◽  
Model Comparison ◽  
Climate Impacts ◽  
Limited Area ◽  
Urban Greening ◽  
Local Climate ◽  
The Impact ◽  
Policy Scenarios

<p>Understanding the impact of urban environments on the local climate has been a crucial topic in recent years. Changes in the cities structure are expected due to the ongoing urbanization trends and climate-aware mitigation planning. These policy implementations are expected to affect the local urban surface and its interaction with the climate system. Here, we are interested in investigating these impacts coupled to a heatwave condition, due to its adverse impact on human health. </p> <p>In the presented work, we investigate the multi-model response to different urbanization and urban greening scenarios. We employ two NWP models at the 2.1 km convection-permitting resolution: ICON-LAM (ICOsahedral Nonhydrostatic Model in Limited Area Mode)  and WRF-ARW (Weather Research and Forecasting Model). Our one-month experiments comprise the 2019 ``record-breaking'' heatwave in Western Europe and they are all a downscaling of ICON-EU (6.5km resolution).</p> <p>The urban policy scenarios are built from the CORINE land use dataset and they include two urbanization and two urban greening settings, for each model. Urbanization is represented as a sprawl of the main urban areas within the domain towards the natural surrounding areas. To increase the urban green fraction within the main cities, we increase the number of green areas within each city.</p> <p>Our analysis shows the multi-model comparison of the effects of the mentioned urban policies on the urban heat island (UHI) under heatwave conditions. Further, we quantify the effects of urban greening as an efficient tool to mitigate expected climate impacts in terms of the Discomfort Index, and not just for the UHI.<br />Further, we evaluate the similarities and dissimilarities between the two models in terms of multiple correlation decomposition accordingly to Glowienka-Hense et al. 2020.</p>

Hybrid model for the prediction of municipal solid waste generation in Hangzhou, China

2019 ◽  
Vol 37 (8) ◽  
pp. 781-792
Author(s):  
Zhenying Zhang ◽  
Yuxiang Zhang ◽  
Dazhi Wu
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Hybrid Model ◽  
Urban Areas ◽  
Waste Treatment ◽  
Percentage Error ◽  
Waste Generation ◽  
Population Total ◽  
The Future ◽  
The Individual

Accurate prediction of municipal solid waste (MSW) generation is necessary for choosing appropriate waste treatment methods and for planning the distribution of disposal facilities. In this study, a hybrid model was established to forecast MSW generation through the combination of the ridge regression and GM(1,N) models. The hybrid model is multivariate and involves total urban population, total retail sales of social consumer goods, per capita consumption expenditure of urban areas, tourism, and college graduation. Compared with the constituent models alone, the hybrid model yields higher accuracy, with a mean absolute percentage error (MAPE) of only 2.59%. Through weight allocation and optimal treatment of residuals, the hybrid model also balances the growth trends of the individual models, making the prediction curve smoother. The model coefficients and correlation analysis show that population, economics, and educational factors are influential for waste generation. MSW output in Hangzhou will gradually increase in the future, and is expected to reach 5.12 million tons in 2021. Results can help decision makers to develop the measures and policies of waste management in the future.

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