scholarly journals Temporal changes in greenspace in a highly urbanized region

2011 ◽  
Vol 7 (5) ◽  
pp. 763-766 ◽  
Author(s):  
Martin Dallimer ◽  
Zhiyao Tang ◽  
Peter R. Bibby ◽  
Paul Brindley ◽  
Kevin J. Gaston ◽  
...  

The majority of the world's population now lives in towns and cities, and urban areas are expanding faster than any other land-use type. In response to this phenomenon, two opposing arguments have emerged: whether cities should ‘sprawl’ into the wider countryside, or ‘densify’ through the development of existing urban greenspace. However, these greenspaces are increasingly recognized as being central to the amelioration of urban living conditions, supporting biodiversity conservation and ecosystem service provision. Taking the highly urbanized region of England as a case study, we use data from a variety of sources to investigate the impact of national-level planning policy on temporal patterns in the extent of greenspace in cities. Between 1991 and 2006, greenspace showed a net increase in all but one of 13 cities. However, the majority of this gain occurred prior to 2001, and greenspace has subsequently declined in nine cities. Such a dramatic shift in land use coincides with policy reforms in 2000, which favoured densification. Here, we illustrate the dynamic and policy-responsive nature of urban land use, thereby highlighting the need for a detailed investigation of the trade-offs associated with different mechanisms of urban densification to optimize and secure the diverse benefits associated with greenspaces.

2020 ◽  
Vol 12 (7) ◽  
pp. 1186 ◽  
Author(s):  
A.-M. Olteanu-Raimond ◽  
L. See ◽  
M. Schultz ◽  
G. Foody ◽  
M. Riffler ◽  
...  

Land use and land cover (LULC) mapping is often undertaken by national mapping agencies, where these LULC products are used for different types of monitoring and reporting applications. Updating of LULC databases is often done on a multi-year cycle due to the high costs involved, so changes are only detected when mapping exercises are repeated. Consequently, the information on LULC can quickly become outdated and hence may be incorrect in some areas. In the current era of big data and Earth observation, change detection algorithms can be used to identify changes in urban areas, which can then be used to automatically update LULC databases on a more continuous basis. However, the change detection algorithm must be validated before the changes can be committed to authoritative databases such as those produced by national mapping agencies. This paper outlines a change detection algorithm for identifying construction sites, which represent ongoing changes in LU, developed in the framework of the LandSense project. We then use volunteered geographic information (VGI) captured through the use of mapathons from a range of different groups of contributors to validate these changes. In total, 105 contributors were involved in the mapathons, producing a total of 2778 observations. The 105 contributors were grouped according to six different user-profiles and were analyzed to understand the impact of the experience of the users on the accuracy assessment. Overall, the results show that the change detection algorithm is able to identify changes in residential land use to an adequate level of accuracy (85%) but changes in infrastructure and industrial sites had lower accuracies (57% and 75 %, respectively), requiring further improvements. In terms of user profiles, the experts in LULC from local authorities, researchers in LULC at the French national mapping agency (IGN), and first-year students with a basic knowledge of geographic information systems had the highest overall accuracies (86.2%, 93.2%, and 85.2%, respectively). Differences in how the users approach the task also emerged, e.g., local authorities used knowledge and context to try to identify types of change while those with no knowledge of LULC (i.e., normal citizens) were quicker to choose ‘Unknown’ when the visual interpretation of a class was more difficult.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Xinli Ke ◽  
Feng Wu ◽  
Caixue Ma

Urban land expansion plays an important role in climate change. It is significant to select a reasonable urban expansion pattern to mitigate the impact of urban land expansion on the regional climate in the rapid urbanization process. In this paper, taking Wuhan metropolitan as the case study area, and three urbanization patterns scenarios are designed to simulate spatial patterns of urban land expansion in the future using the Partitioned and Asynchronous Cellular Automata Model. Then, simulation results of land use are adjusted and inputted into WRF (Weather Research and Forecast) model to simulate regional climate change. The results show that: (1) warming effect is strongest under centralized urbanization while it is on the opposite under decentralized scenario; (2) the warming effect is stronger and wider in centralized urbanization scenario than in decentralized urbanization scenario; (3) the impact trends of urban land use expansion on precipitation are basically the same under different scenarios; (4) and spatial distribution of rainfall was more concentrated under centralized urbanization scenario, and there is a rainfall center of wider scope, greater intensity. Accordingly, it can be concluded that decentralized urbanization is a reasonable urbanization pattern to mitigate climate change in rapid urbanization period.


2013 ◽  
Vol 726-731 ◽  
pp. 4645-4649
Author(s):  
Jia Hua Zhang ◽  
Cui Hao ◽  
Feng Mei Yao

We developed an approach to assess urban land use changes that incorporates socio-economic and environmental factors with multinomial logistic model, remote sensing data and GIS, and to quantify the impact of macro variables on land use of urban areas for the years 1990, 2000 and 2010 in Binhai New Area, China. The Markov transition matrix was designed to integrate with multinomial logistic model to illustrate and visualize the predicted land use surface. The multinomial logistic model was evaluated by means of Likelihood ratio test and Pseudo R-Square and showed a relatively good simulation. The prediction map of 2010 showed accurate rates 78.54%, 57.25% and 70.38%, respectively.


2020 ◽  
Author(s):  
Gara Villalba ◽  
Sergi Ventura ◽  
Joan Gilabert ◽  
Alberto Martilli ◽  
Alba Badia

<p>Currently, around 54% of the world's population is living in urban areas and this number is projected to increase by 66% by 2050. In the past years, cities have been experiencing heat wave episodes that affect the population. As the modern urban landscape is continually evolving, with green spaces and parks becoming a more integral component and with suburbs expanding outward from city centres into previously rural, agricultural, and natural areas, we need tools to learn how to best implement planning strategies that minimize heat waves.  In this study we use the Weather and Research Forecasting model (WRF) with a multi-layer layer scheme, the Building Effect Parameterization (BEP) coupled with the Building Energy Model (BEP+BEM, Salamanca and Martilli, 2010) to take into account the energy consumption of buildings and anthropogenic heat generated by air conditioning systems. The urban canopy scheme takes into account city morphology (e.g. building and street canyon geometry) and surface characteristics (e.g. albedo, heat capacity, emissivity, urban/vegetation fraction). The Community Land Surface Model (CLM) is used in WRF that uses 16 different plant functional types (PFTs) as the basis for land-use differentiation.  Furthermore, we use the Local Climate Zones (LCZ) classification which has 11 urban land use categories with specific thermal, radiative and geometric parameters of the buildings and ground to compute the heat and momentum fluxes in the urban areas.  The objective is to validate the model and establish relationships between urban morphology and land use with temperature, so that the model can be used to simulate land use scenarios to investigate the effectiveness of different mitigation strategies to lower urban temperatures during the summer months.</p><p> </p><p>We test the methods with the Metropolitan Area of Barcelona (AMB) as a case study. The AMB is representative of the Mediterranean climate, with mild winters and hot summers. With a heterogeneous urban landscape, the AMB covers 636 km<sup>2 </sup>(34% built, 23% agricultural, and 31% vegetation) and has more than five million habitants. We simulate the heat wave that occurred in August 2018, during which temperatures stayed between 30 and 40ºC for five consecutive days and compare results with observed data from five different weather stations. We then simulate a potential scenario changing land surface from built to vegetation, in accordance with Barcelona´s strategic climate plan, and the potential impact the land use change has on reducing heat wave episodes.</p>


2014 ◽  
Vol 11 ◽  
pp. 351-355
Author(s):  
Stefano Corsi ◽  
Chiara Mazzocchi ◽  
Giovanni Mottadelli ◽  
Guido Sali

Participation in planning has become progressively important in territory management. As regards Territorial Planning, farmers are among the main stakeholders. In fact multifunctionality of agriculture admits a new role to primary sector. In particular the management of open areas is particularly strategic in peri-urban areas, where competition for resources is highest than in other areas, especially for the land. In this context, the involvement of farmers as privileged stakeholders to land management is even more important. This paper proposes a methodological approach for the evaluation of peri-urban land use plans by farmers. In particular, it has been considered the "Territorial Action Plan of Valencias Huerta (TAPVH).


2014 ◽  
Vol 46 (11) ◽  
pp. 2769-2785 ◽  
Author(s):  
Chris Jacobs-Crisioni ◽  
Piet Rietveld ◽  
Eric Koomen ◽  
Emmanouil Tranos

Dense and mixed land-use configurations are assumed to encourage high and prolonged activity levels, which in turn are considered to be important for the condition of urban neighbourhoods. We used mobile phone usage data recorded in Amsterdam, the Netherlands, as a proxy for urban activity to test whether the density in different forms of urban land use increases the level of activity in urban areas, and whether mixed land uses can prolong high levels of activity in an area. Our results indicate that higher densities correspond with higher activity levels, mixed land uses do indeed diversify urban activity dynamics and colocating particular land uses prolongs high activity levels in the evening hours. We proceed to demonstrate that mixed activity provisions and high urban activity levels coincide with urban neighbourhoods that are considered attractive places in which to live and work, while lower activity levels and markedly low activity mixes coincide with neighbourhoods that are considered disadvantaged.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hikari Shimadera ◽  
Akira Kondo ◽  
Kundan Lal Shrestha ◽  
Ken Kitaoka ◽  
Yoshio Inoue

This study utilized the Weather Research and Forecasting (WRF) model version 3.5.1 to evaluate the impact of urbanization on summertime precipitation in Osaka, Japan. The evaluation was conducted by comparing the WRF simulations with the present land use and no-urban land use (replacing “Urban” with “Paddy”) for August from 2006 to 2010. The urbanization increased mean air temperature by 2.1°C in urban areas because of increased sensible heat flux and decreased mean humidity by 0.8 g kg−1because of decreased latent heat flux. In addition, the urbanization increased duration of the southwesterly sea breeze. The urbanization increased precipitation in urban areas and decreased in the surrounding areas. The mean precipitation in urban areas was increased by 20 mm month−1(27% of the total amount without the synoptic-scale precipitation). The precipitation increase was generally due to the enhancement of the formation and development of convective clouds by the increase in sensible heat flux during afternoon and evening time periods. The urbanization in Osaka changes spatial and temporal distribution patterns of precipitation and evaporation, and consequently it substantially affects the water cycle in and around the urban areas of Osaka.


2019 ◽  
Vol 8 (1) ◽  
pp. 37-56
Author(s):  
Joseph Kwaku Kidido ◽  
John Tiah Bugri

This study examines youth access to agricultural land from both peri-urban and rural perspectives. Using the Techiman area as a case study, the study interviewed youth and elders made up of chiefs and family heads using multiple random sampling techniques. The results revealed that, the youth generally have access to small landholdings whether in the peri-urban or rural context. These small holdings were a manifestation of the challenges underling the youth access to land under customary system. The predominant challenges facing the youth included; high rental/acquisition cost, land scarcity and land disputes. The youth also suffered more from the urbanisation effects, but do not benefit from proceeds arising out of peri-urban land use conversions. The study recommends youth agricultural land access policy and a compensation regime which benefits both the youth and adults in land use conversions in the peri-urban areas of Ghana.


2019 ◽  
Vol 43 (43) ◽  
pp. 71-89 ◽  
Author(s):  
Ali Soltani ◽  
Rasoul Balaghi Inaloo ◽  
Mohammad Rezaei ◽  
Fatemeh Shaer ◽  
M. Akbari Riyabi

AbstractProviding appropriate and equal healthcare to the various classes of society is among the major issues in social welfare. The spatial distribution and locating of health service centres are significant in addressing the healthcare needs of citizens. This issue needs to be evaluated using quantitative and qualitative approaches throughout those cities with high populations and activity density levels. By taking Isfahan metropolitan area as the case study area, in this study, a combination of Network Analyst tool within Geographic Information System (GIS) and an Analytic Hierarchy Process (AHP) model was used to evaluate the catchment areas of the 26 existing hospitals within the study area. Thus, with effective data collection in the form of layers of information such as transportation network, population density, land use, etc. using (GIS), the authors categorised urban land in seven categories from poor to very good for the construction of hospitals. The result of analysis indicated that existing hospitals covered approximately 24% of active urban areas within a standard access time. The result can be used for policy making and healthcare planning.


2021 ◽  
Author(s):  
Berkay Dönmez ◽  
Kutay Dönmez ◽  
Deniz Diren-Üstün ◽  
Yurdanur Ünal

<p>Studies concerning the effects of urbanization on heavy precipitation events mostly focused on the summertime convective precipitation events. In these studies, the Urban Heat Island (UHI) effect was prominent over the urbanized region before the event, changing the spatial and temporal distribution of the precipitation. We aim to reveal the impact of urbanization over Ankara on the springtime frontal precipitation event of 5 May 2014, when the ground heating and UHI effects are not as strong as those in the summertime. We performed two different simulations based on the land-use scenarios with urban (URBAN) and without urban areas (NOURBAN) over Ankara, integrating the CORINE Land Use dataset into the Weather Research and Forecasting Model (WRF v3.8) and replacing the urban areas with the dominant land use category over the region. Four sub-regions with the identical area coverages corresponding to the upwind, central, and downwind parts of the city center are defined to have a lucid spatial and temporal representation of the event. The two simulation results agreed reasonably with the observations. In the simulation (URBAN) with the urban land use included, the spatial average of the daily rainfall amounts over the predefined sub-regions slightly decreased, especially the sub-regions to the upwind and downwind of the highly urbanized area. However, the difference in precipitation amount in the vicinity of the urbanized area between the two different simulations is not of significance in comparison to what was observed in other summertime precipitation studies. On the other hand, the UHI effect might be crucial in determining the impact of urban land use on the distribution and magnitude of the heavy springtime rainfall. To support this idea, we performed a similar analysis for a summertime convective precipitation event over Ankara and compared the results.</p>


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