scholarly journals Temporal and Spatial Aspects of Velocity Variance in the Urban Surface Roughness Layer

2013 ◽  
Vol 52 (3) ◽  
pp. 668-681 ◽  
Author(s):  
Bruce B. Hicks ◽  
Elena Novakovskaia ◽  
Ronald J. Dobosy ◽  
William R. Pendergrass ◽  
William J. Callahan
Keyword(s):  
Surface Roughness ◽  
Urban Areas ◽  
Average Velocity ◽  
Suburban Areas ◽  
Approximate Equality ◽  
Velocity Variance ◽  
Two Measures ◽  
Temporal And Spatial ◽  
Velocity Variances ◽  
Average State

AbstractData from six urban areas in a nationwide network of sites within the surface roughness layer are examined. It is found that the average velocity variances in time, derived by averaging the conventional variances from a network of n stations, are nearly equal to the velocity variances in space, derived as the variances among the n average velocities. This similarity is modified during sunlit hours, when convection appears to elevate the former. The data show little dependence of the ratio of these two variances on wind speed. It is concluded that the average state of the surface roughness layer in urban and suburban areas like those considered here tends toward an approximate equality of these two measures of variance, much as has been observed elsewhere for the case of forests.

scholarly journals A multiscale assessment of Red-tailed Hawk reproductive success relative to urban density and habitat type

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Justin H White ◽  
Jessi L Brown ◽  
Zachary E Ormsby
Keyword(s):  
Urban Areas ◽  
Urban Expansion ◽  
Habitat Type ◽  
Nesting Success ◽  
Arid Environments ◽  
Hatch Date ◽  
Urban Density ◽  
Landscape Characteristics ◽  
Suburban Areas ◽  
Breeding Seasons

Abstract Despite the unique threats to wildlife in urban areas, many raptors have established successfully reproducing urban populations. To identify variations in raptor breeding ecology within an urban area, we compared metrics of Red-tailed Hawk reproductive attempts to landscape characteristics in Reno and Sparks, NV, USA during the 2015 and 2016 breeding seasons. We used the Apparent Nesting Success and logistic exposure methods to measure nesting success of the Red-tailed Hawks. We used generalized linear models to relate nesting success and fledge rate to habitat type, productivity to hatch date (Julian day) and hatch date to urban density. Nesting success was 86% and 83% for the respective years. Nesting success increased in grassland-agricultural and shrub habitats and decreased in riparian habitat within the urban landscape. Productivity was 2.23 and 2.03 per nest for the breeding seasons. Fledge rates were 72% and 77%, respectively, and decreased in riparian areas. Nestlings hatched earlier with increased urban density and earliest in suburban areas, following a negative quadratic curve. Nesting success and productivity for this population were high relative to others in North America. Productivity increased in habitats where ground prey was more accessible. We suggest that suburban areas, if not frequently disturbed, provide sufficient resources to sustain Red-tailed Hawks over extended periods. As urban expansion continues in arid environments globally, we stress that researchers monitor reproductive output across the urban predator guild to elucidate patterns in population dynamics and adaptation.

scholarly journals InSAR Multitemporal Data over Persistent Scatterers to Detect Floodwater in Urban Areas: A Case Study in Beletweyne, Somalia

2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Luca Pulvirenti ◽  
Marco Chini ◽  
Nazzareno Pierdicca
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
The Other ◽  
Spatial Average ◽  
Calibration Data ◽  
Suburban Areas ◽  
Persistent Scatterers ◽  
Optical Images ◽  
Interferometric Phase ◽  
Multitemporal Data

A stack of Sentinel-1 InSAR data in an urban area where flood events recurrently occur, namely Beletweyne town in Somalia, has been analyzed. From this analysis, a novel method to deal with the problem of flood mapping in urban areas has been derived. The approach assumes the availability of a map of persistent scatterers (PSs) inside the urban settlement and is based on the analysis of the temporal trend of the InSAR coherence and the spatial average of the exponential of the InSAR phase in each PS. Both interferometric products are expected to have high and stable values in the PSs; therefore, anomalous decreases may indicate that floodwater is present in an urban area. The stack of Sentinel-1 data has been divided into two subsets. The first one has been used as a calibration set to identify the PSs and determine, for each PS, reference values of the coherence and the spatial average of the exponential of the interferometric phase under standard non-flooded conditions. The other subset has been used for validation purposes. Flood maps produced by UNOSAT, analyzing very-high-resolution optical images of the floods that occurred in Beletweyne in April–May 2018, October–November 2019, and April–May 2020, have been used as reference data. In particular, the map of the April–May 2018 flood has been used for training purposes together with the subset of Sentinel-1 calibration data, whilst the other two maps have been used to validate the products generated by applying the proposed method. The main product is a binary map of flooded PSs that complements the floodwater map of rural/suburban areas produced by applying a well-consolidated algorithm based on intensity data. In addition, a flood severity map that labels the different districts of Beletweyne, as not, partially, or totally flooded has been generated to consolidate the validation. The results have confirmed the effectiveness of the proposed method.

What Kind of People Use Carsharing for Commuting? Case Study in Shanghai

2019 ◽  
Vol 2673 (5) ◽  
pp. 770-778 ◽  
Author(s):  
Jianhong Ye ◽  
Daoge Wang ◽  
Hua Zhang ◽  
Hong Yang
Keyword(s):  
High Frequency ◽  
Urban Areas ◽  
Descriptive Analysis ◽  
User Characteristics ◽  
Logistic Regression Models ◽  
Highly Educated ◽  
Suburban Areas ◽  
Commuting Mode ◽  
Study Offer

Carsharing as a service has been growing rapidly worldwide. Its expansion has drawn wide attention in the research community with regard to the underlying driving factors and user characteristics. Despite these extensive investigations, there are still limited studies focusing on the examination of users using carsharing as a commuting mode. The answers to questions such as what kind of people would like to use carsharing for commuting and why they frequently use carsharing to commute are not clear. To enrich our understanding of these problems, this paper aims to investigate carsharing commuters in a mega city. Specifically, it intends to integrate the actual user order data with survey data from 1,920 participants to uncover the characteristics of carsharing commuters. Data from the Evcard carsharing systems in Shanghai were explicitly analyzed. Through descriptive analysis and logistic regression models, the characteristics and critical factors that affect the choice of carsharing as a commuting mode were captured. The results show that: 1. carsharing commuters mostly live or work in suburban areas in which public transport accessibility is limited; 2. carsharing commuters are more likely to be highly educated, in a higher income bracket, and older than other carsharing members; 3. high-frequency carsharing commuters own a reduced number of private cars; and 4. those high-frequency carsharing commuters with higher income are less sensitive to the carsharing costs caused by congestion. The findings in the study offer some insights into carsharing commuters and provide some supportive information for considering policies in developing carsharing systems in urban areas.

Ophthalmic Screening of School Children in Ankara

1995 ◽  
Vol 5 (3) ◽  
pp. 181-186 ◽  
Author(s):  
M.E. Turaçli ◽  
S.G. Aktan ◽  
K. Dürük
Keyword(s):  
School Children ◽  
Urban Areas ◽  
Primary Schools ◽  
Screening Program ◽  
Primary School Children ◽  
Refractive Errors ◽  
Normal Visual Acuity ◽  
Good State ◽  
State Schools ◽  
Average State

Ophthalmic screening was done on 23,810 children visited at schools in different regions of Ankara. Children with below normal visual acuity were invited to the outpatient department and had a full routine ocular examination. Thirty-nine nursery and primary schools were selected, ten of them private, eleven average state schools, seven good state schools and eleven village schools. Among the 23,810 children, 3095 (13%) had various pathology; 1516 were girls, 1579 boys. Refractive errors were found in 85% of the children (2630). This equals 11% of the total screened population. Refractive errors were myopia 32%, hypermetropia 21%, astigmatism 47%. Strabismic children were 2.5%, and amblyopia was found in 1.1%. The purpose of the study was to assess the place of an ocular screening program in primary school children and to discuss the differences encountered in different urban areas.

scholarly journals Temporal–Spatial Patterns of Relative Humidity and the Urban Dryness Island Effect in Beijing City

2017 ◽  
Vol 56 (8) ◽  
pp. 2221-2237 ◽  
Author(s):  
Ping Yang ◽  
Guoyu Ren ◽  
Wei Hou
Keyword(s):  
Relative Humidity ◽  
Urban Areas ◽  
Late Summer ◽  
Beijing City ◽  
Near Surface ◽  
Suburban Areas ◽  
Island Effect ◽  
Different Seasons ◽  
Autumn And Winter ◽  
Beijing China

AbstractHourly datasets obtained by automatic weather stations in Beijing, China, are developed and employed to analyze the spatial and temporal characteristics of relative humidity (RH) and urban dryness island intensity (UDII) over built-up areas. A total of 36 stations inside the sixth ring road are considered as urban sites, while six stations in suburban belts surrounding the built-up areas are taken as reference sites. Results show that the RH is obviously smaller in urban areas than in suburban areas, indicating the effect of urbanization on near-surface atmospheric moisture and RH. A further analysis of relations between RH and temperature on varied time scales shows that the variations in RH in the urban areas are not due solely to changes in temperature. The annual and seasonal mean UDII are high in central urban areas, with the strongest UDII values occurring in autumn and the weakest values occurring in spring. The diurnal UDII variations are characterized by a steadily strong UDII stage from 2000 to 0800 LT and a minimum at 1500 or 1600 LT. The rapid shifts of UDII from high (low) to low (high) occur during the periods 0800–1600 LT (1600–2000 LT). The occurrence time of the peaks varies among different seasons: the peaks appear at 0700, 2100, 2000, and 0800 LT for spring, summer, autumn, and winter, respectively. Further analysis shows that large UDII values appear in the evenings and early nights in late summer and early to midautumn and that low UDII values mainly occur in the afternoon hours of spring, winter, and late autumn.

scholarly journals Housing Resources and Needs in Light of Modern Urban Transformations: the Case of Poznan

2017 ◽  
Vol 25 (2) ◽  
pp. 72-78
Author(s):  
Sławomir Palicki
Keyword(s):  
Urban Sprawl ◽  
Urban Areas ◽  
Local Governments ◽  
Real Estate Market ◽  
Capital City ◽  
Central Cities ◽  
The Real Estate ◽  
Suburban Areas ◽  
Starting Point ◽  
Urban Transformations

Abstract Polish cities have been at the stage of a dynamic suburban development for over a decade (which has led to the phenomenon of urban sprawl beyond any control). The population of big urban areas, together with their agglomerations is continuously increasing; however, migration tendencies towards suburban areas are strong as well. In such a situation, the question arises regarding the possibilities and the methods of suppressing the outflow of people to the neighboring communities, and once again, making the city an attractive place to live. The attempt to explain such an issue requires research into both the housing infrastructure and its inhabitants. Poznan has been severely affected by suburbanization. The diagnosis and assessment of Poznan housing resources and the preferences of its inhabitants are the starting point for taking further steps in making the housing conditions more attractive. The article shows the initial results of widespread research regarding housing in the capital city of the Wielkopolska Province (comprising over 2,500 households). A similar study for the entire agglomeration (Poznan County) is due to be completed soon. It will allow for a comparative analysis and formulating recommendations regarding the conditions and the direction of changes on the real estate market which would increase the attractiveness of central cities suffering from suburbanization. In a wider context, the publication might be seen as an analysis of one of the elements of modern urban changes, such as either market driven, or free and spontaneous processes of urban sprawl, and conscious actions taken by local governments (together with developers) regarding the integrated urban revitalization policy.

scholarly journals Spatial development and transport accessibility in Wroclaw suburbs, for example Siechnice, Smolec and Długołęka

2018 ◽  
Vol 2018 (2) ◽  
pp. 1-10 ◽  
Author(s):  
Marek Jaskólski ◽  
Mateusz Smolarski
Keyword(s):  
Urban Areas ◽  
Spatial Planning ◽  
Spatial Development ◽  
Transportation Systems ◽  
Transport Policy ◽  
Transport Network ◽  
Main Theme ◽  
Low Density ◽  
Suburban Areas ◽  
Dynamic Growth

Suburbanization affects on spatial planning and transport policy in urban areas. The main theme of this report is to show how the transport network react to the chaotic and dynamic growth of suburban areas. Authors show spatial growth on three examples. The paper also tries to prove that with the growing trend toward suburbanization, more effective transportation systems must be developed to meet the needs of the low-density, suburban population. Authors refer to the process of suburbanization onexamples from Wroclaw and the surrounding locality.

scholarly journals QUALIDADE AMBIENTAL DA ÁGUA SUPERFICIAL DO CÓRREGO QUATRO VINTÉNS NO MUNICÍPIO DE DIAMANTINA-MG

2020 ◽  
Vol 14 (01) ◽  
pp. 77-95
Author(s):  
Amanda Dias Araujo ◽  
Mariana de Oliveira Freitas ◽  
Hernando Baggio Filho
Keyword(s):  
Water Samples ◽  
Urban Areas ◽  
Environmental Geochemistry ◽  
Palabras Clave ◽  
Two Measures ◽  
Del Rio ◽  
Intensive Land Use ◽  
The City ◽  
Dry And Rainy Seasons

O Córrego Quatro Vinténs faz parte da bacia hidrográfica do rio Jequitinhonha, localizado no município de Diamantina-MG. Neste trabalho avaliou-se a qualidade ambiental das águas superficiais deste córrego por meio da medição de dois parâmetros físico-químicos cor da água e turbidez. Com o recolhimento de amostras ao longo do canal do córrego foi possível relacionar os impactos aos ambientes naturais e às interferências antropogênicas, englobando as características geoambientais da área. Foram amostrados 12 pontos considerando a variação sazonal em duas campanhas de amostragem (nas estações seca e chuvosa), totalizando 24 amostras de água. As amostras foram analisadas no Laboratório de Geoquímica Ambiental – LGA/UFVJM e os resultados comparados com os valores estabelecidos pela Resolução CONAMA 357/05 e Portaria do Ministério da Saúde N° 2.914/2011. Os valores de turbidez (UNT) e cor da água (mg/L), tanto numa estação quanto noutra se apresentaram elevados, haja vista que a área está totalmente inserida em locais de uso intensivo do solo e áreas urbanas. Palavras-chave: Geoquímica Ambiental; Córrego Quatro Vinténs; Serra do Espinhaço Meridional.   ENVIRONMENTAL QUALITY STREAM OF SURFACE WATER IN QUATRO VINTÉNS DIAMANTINA MUNICIPALITY – MG Abstract The Quatro Vintens stream part of the basin of the Jequitinhonha River, which is located in the city of Diamantina. The aim of this work is to evaluate the environmental geochemistry quality of superficial waters of this stream through two measures physical-chemical parameters water color and turbidity. Collecting samples along the stream channel was possible to relate to natural and anthropogenic interference environments, encompassing geo-environmental characteristics of the area. 12 points were sampled considering the seasonal variation in two sampling campaigns (in the dry and rainy seasons), totaling 24 water samples. Water samples were analyzed in the Environmental Geochemistry Laboratory - LGA/UFVJM and the results compared to the values ​​established by CONAMA Resolution 357/05 and Ordinance of the Ministry of Health N°. 2.914/2011. The turbidity values ​​(UNT) and color of the water (mg/L), both at a station in another as the values ​​presented high, given that the area is fully inserted in places of intensive land use and urban areas. Keywords: Environmental Geochemistry; Quatro Vinténs Stream; Diamantina; Espinhaço Meridional Ranger.   CALIDAD AMBIENTAL SECUENCIA DEL AGUA DE SUPERFICIE EN QUATRO VINTÉNS DIAMANTINA – MG Resumen La corriente Quatro Vinténs es parte de la cuenca del río Jequitinhonha, que se encuentra en la ciudad de Diamantina-MG. En este trabajo se evaluó la calidad ambiental de las aguas superficiales de esta corriente mediante la medición de dos parámetros físico-químicos del color de agua y turbidez. Con la toma de muestras a lo largo del canal de flujo fue posible relacionar los impactos en el medio ambiente natural y la interferencia antropogénica que abarca las características geo-ambientales de la zona. 12 puntos fueron muestreados teniendo en cuenta la variación estacional en dos campañas de muestreo (en las estaciones seca y lluviosa), un total de 24 muestras de agua. Las muestras fueron analizadas en el Laboratorio de Geoquímica Ambiental - LGA/UFVJM y los resultados en comparación con los valores establecidos por la Resolución CONAMA 357/05 y Decreto del Ministerio de Salud N° 2.914/2011. Los valores de turbidez (NTU) y color del agua (mg/L), tanto como una estación en otro presentan alta, teniendo en cuenta que la zona esté completamente insertado en el uso local de la tierra intensivo y áreas urbanas. Palabras-clave: Geoquímica Ambiental; Codificar Quatro Vinténs; Serra do Espinhaço.

Spatiotemporal Dynamics of Urban Parks and Their Driving Forces in Xi'an, China from 1949 to 2015

2017 ◽  
Vol 42 (3) ◽  
pp. 112-115
Author(s):  
Xuhui Wang ◽  
Kewei Liu ◽  
Kai Wang ◽  
Jian Gong ◽  
Yanjun Wang ◽  
...  
Keyword(s):  
Urban Areas ◽  
Green Space ◽  
Driving Forces ◽  
Urban Parks ◽  
Spatiotemporal Dynamics ◽  
Green Spaces ◽  
Space Planning ◽  
Suburban Areas ◽  
Human Wellbeing ◽  
Average Size

Urban parks play a key role in recreational activities, public health, and ecosystem services in urban areas. Using GIS and Fragstats, this study investigated the spatiotemporal dynamics of urban parks in Xi'an, China from 1949 to 2015 and the corresponding driving forces. The results show that the number and area of parks in Xi'an increased constantly during this period, especially from 2000 to 2015. Up to 2015, small green spaces, usually adjacent to streets, occupied the largest proportion among all types of parks. Archaeological parks were the largest in total area, but wetland parks were leading in average size of a single park. The density of parks was negatively correlated with their distance to the Clock Tower at the center of Xi'an. The dynamics of urban parks in highly urbanized areas were significantly different from that of their counterparts in suburban areas. Driving forces such as urban planning, urbanization and green space policies, and milestone events in the city's development jointly had a great effect on the distribution of parks in Xi'an. The research outcomes will support the upcoming Green Space Planning of Xi'an and benefit the pursuit of sustainability and human wellbeing.

scholarly journals Characteristics of wintertime VOCs in suburban and urban Beijing: concentrations, emission ratios, and festival effects

2019 ◽  
Author(s):  
Kun Li ◽  
Junling Li ◽  
Shengrui Tong ◽  
Weigang Wang ◽  
Ru-Jin Huang ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Diurnal Variations ◽  
Urban Site ◽  
Anthropogenic Emissions ◽  
Suburban Areas ◽  
Key Characteristics ◽  
Volatile Organic ◽  
Suburban Site ◽  
Emission Ratios

Abstract. Measurements of volatile organic compounds (VOCs) were performed at a suburban site and an urban site in Beijing during the winter of 2014–2015. The VOC concentrations and emission ratios (ERs) to CO were compared at these two sites. It is found that though the VOC concentrations at the urban site are 2.67 ± 1.15 times of those at the suburban site, the ERs are similar (within a factor of 1.5). It is indicated that: (1) the VOCs at suburban areas are mainly from the transportation from the urban areas; (2) the ERs measured at the urban areas are also valid for the surrounding suburban areas. By comparing the diurnal variations and the contribution of anthropogenic emissions at both sites, we find that the photochemical processes are very active at the urban site, and these processes play an important role in the daytime oxygenated VOCs (OVOCs) formation. The methanol at the urban site and the formic acid at the suburban site probably have additional sources, which are attributed to be solvent use and soil/agriculture, respectively. The festival effects from Chinese New Year (CNY) were investigated. The VOC concentrations decreased ~ 60 % during CNY holidays, probably due to the population migration during festival holidays. In addition, fireworks are found to be an important source of acetonitrile, aromatics, and some OVOCs during CNY festival, and should be controlled more strictly. This study provides key characteristics of wintertime VOCs in suburban and urban Beijing, and has implications for better understanding the atmospheric chemistry of VOCs in and around this megacity.

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