Assessing the impact of the urban landscape on heat wave episodes: a case study of the Metropolitan Area of Barcelona.

2020 ◽  
Author(s):  
Gara Villalba ◽  
Sergi Ventura ◽  
Joan Gilabert ◽  
Alberto Martilli ◽  
Alba Badia
Keyword(s):  
Land Use ◽  
Heat Wave ◽  
Metropolitan Area ◽  
Land Surface ◽  
Urban Areas ◽  
Urban Landscape ◽  
Urban Land Use ◽  
Anthropogenic Heat ◽  
Surface Model

<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>

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 ◽  
...  
Keyword(s):  
Land Use ◽  
Urban Areas ◽  
National Level ◽  
Urban Land Use ◽  
Policy Reforms ◽  
Trade Offs ◽  
Dramatic Shift ◽  
Urbanized Region ◽  
The Impact

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.

scholarly journals Impact of an improved WRF urban canopy model on diurnal air temperature simulation over northern Taiwan

2016 ◽  
Vol 16 (3) ◽  
pp. 1809-1822 ◽  
Author(s):  
Chuan-Yao Lin ◽  
Chiung-Jui Su ◽  
Hiroyuki Kusaka ◽  
Yuko Akimoto ◽  
Yang-Fan Sheng ◽  
...  
Keyword(s):  
Land Surface ◽  
Urban Areas ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Surface Model ◽  
Urban Canopy Model ◽  
Simulation Performance ◽  
The Impact ◽  
Canopy Model ◽  
Northern Taiwan

Abstract. This study evaluates the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) Model coupled with the Noah land-surface model and a modified urban canopy model (WRF–UCM2D). In the original UCM coupled to WRF (WRF–UCM), when the land use in the model grid is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. This may not only lead to over- or underestimation of urban fraction and AH in urban and non-urban areas, but spatial variation also affects the model-estimated temperature. To overcome the abovementioned limitations and to improve the performance of the original UCM model, WRF–UCM is modified to consider the 2-D urban fraction and AH (WRF–UCM2D).The two models were found to have comparable temperature simulation performance for urban areas, but large differences in simulated results were observed for non-urban areas, especially at nighttime. WRF–UCM2D yielded a higher correlation coefficient (R2) than WRF–UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF–UCM2D were both significantly smaller than those attained by WRF–UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF–UCM2D performed much better than WRF–UCM at non-urban stations with a low urban fraction during nighttime. The improved simulation performance of WRF–UCM2D in non-urban areas is attributed to the energy exchange which enables efficient turbulence mixing at a low urban fraction. The result of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

scholarly journals Farmers’ Participation in Territorial Planning: A Methodological Approach for the Case Study of Huerta de Valencia

2014 ◽  
Vol 11 ◽  
pp. 351-355
Author(s):  
Stefano Corsi ◽  
Chiara Mazzocchi ◽  
Giovanni Mottadelli ◽  
Guido Sali
Keyword(s):  
Land Use ◽  
Land Management ◽  
Urban Areas ◽  
Action Plan ◽  
Methodological Approach ◽  
Urban Land Use ◽  
Territorial Planning ◽  
Territory Management ◽  
Competition For Resources

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).

Youth Access to Agricultural Land from Peri-urban and Rural Perspective: A Study of Techiman Traditional Area in Ghana

2019 ◽  
Vol 8 (1) ◽  
pp. 37-56
Author(s):  
Joseph Kwaku Kidido ◽  
John Tiah Bugri
Keyword(s):  
Land Use ◽  
Urban Areas ◽  
Agricultural Land ◽  
Urban Land Use ◽  
Land Access ◽  
Access Policy ◽  
Land Disputes ◽  
Rural Context ◽  
Traditional Area

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.

Landscape metrics in the analysis of urban land use patterns: A case study in a Spanish metropolitan area

2011 ◽  
Vol 99 (3-4) ◽  
pp. 226-238 ◽  
Author(s):  
Francisco Aguilera ◽  
Luis M. Valenzuela ◽  
André Botequilha-Leitão
Keyword(s):  
Land Use ◽  
Metropolitan Area ◽  
Landscape Metrics ◽  
Urban Land ◽  
Urban Land Use ◽  
Land Use Patterns ◽  
Use Patterns

scholarly journals Impact of Urban Growth on Surface Climate: A Case Study in Oran, Algeria

2009 ◽  
Vol 48 (2) ◽  
pp. 217-231 ◽  
Author(s):  
Lahouari Bounoua ◽  
Abdelmounaine Safia ◽  
Jeffrey Masek ◽  
Christa Peters-Lidard ◽  
Marc L. Imhoff
Keyword(s):  
Land Use ◽  
Land Surface ◽  
Urban Areas ◽  
Hydrological Cycle ◽  
Total Carbon ◽  
Semiarid Region ◽  
Surface Model ◽  
Carbon Uptake ◽  
Mean Temperature ◽  
The Impact

Abstract The authors develop a land use map discriminating urban surfaces from other cover types over a semiarid region in North Africa and use it in a land surface model to assess the impact of urbanized land on surface energy, water, and carbon balances. Unlike in temperate climates where urbanization creates a marked heat island effect, this effect is not strongly marked in semiarid regions. During summer, the urban class results in an additional warming of 1.45°C during daytime and 0.81°C at night relative to that simulated for needleleaf trees under similar climate conditions. Seasonal temperatures show that urban areas are warmer than their surrounding areas during summer and slightly cooler in winter. The hydrological cycle is practically “shut down” during summer and is characterized by relatively large amounts of runoff in winter. The authors estimate the annual amount of carbon uptake to be 1.94 million metric tons with only 11.9% assimilated during the rainy season. However, if urbanization expands to reach 50% of the total area excluding forests, the annual total carbon uptake will decline by 35% and the July mean temperature would increase only 0.10°C relative to the current situation. In contrast, if urbanization expands to 50% of the total land excluding forests and croplands but all short vegetation is replaced by native broadleaf deciduous trees, the annual carbon uptake would increase by 39% and the July mean temperature would decrease by 0.9°C relative to the current configuration. These results provide guidelines for urban planners and land use managers and indicate possibilities for mitigating the urban heat.

scholarly journals Spatial analysis and urban land use planning emphasising hospital site selection: a case study of Isfahan city

2019 ◽  
Vol 43 (43) ◽  
pp. 71-89 ◽  
Author(s):  
Ali Soltani ◽  
Rasoul Balaghi Inaloo ◽  
Mohammad Rezaei ◽  
Fatemeh Shaer ◽  
M. Akbari Riyabi
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Urban Areas ◽  
Urban Land ◽  
Urban Land Use ◽  
Access Time ◽  
Qualitative Approaches ◽  
Healthcare Needs ◽  
Catchment Areas

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.

scholarly journals Impact of an improved WRF-urban canopy model on diurnal air temperature simulation over northern Taiwan

2015 ◽  
Vol 15 (20) ◽  
pp. 28483-28516
Author(s):  
C.-Y. Lin ◽  
C.-J. Su ◽  
H. Kusaka ◽  
Y. Akimoto ◽  
Y. F. Sheng ◽  
...  
Keyword(s):  
Land Surface ◽  
Urban Areas ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Surface Model ◽  
Urban Canopy Model ◽  
Simulation Performance ◽  
The Impact ◽  
Canopy Model ◽  
Northern Taiwan

Abstract. This study evaluated the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) model coupled with the Noah land-surface model and a modified Urban Canopy Model (WRF-UCM2D). In the original UCM coupled in WRF (WRF-UCM), when the land use in the model grid net is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. Such not only may lead to over- or underestimation, the temperature difference between urban and non-urban areas has also been neglected. To overcome the above-mentioned limitations and to improve the performance of the original UCM model, WRF-UCM is modified to consider the 2-D urban fraction and AH (WRF-UCM2D). The two models were found to have comparable simulation performance for urban areas but large differences in simulated results were observed for non-urban, especially at nighttime. WRF-UCM2D yielded a higher R2 than WRF-UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF-UCM2D were both significantly smaller than those attained by WRF-UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF-UCM2D performed much better than WRF-UCM at non-urban stations with low urban fraction during nighttime. The improved simulation performance of WRF-UCM2D at non-urban area is attributed to the energy exchange which enables efficient turbulence mixing at low urban fraction. The achievement of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

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