Search

International audience; The study presents how numerical simulations can be used and complexity to define key indicators for microclimate in eco-district modelling. For eco-district design, policy makers require decision support tools for integration of local environment issues with building design. In a first approach we analyse main environmental parameters that impact building energy performances and open-space thermal comfort. This is a key issue considering the local urban heat island impacts on energy and health. The urban area Cité Descartes is located in Paris suburbs (France) and has been selected in the French eco-district program. One objective is to renew the surroundings of a local train station that separates a low-income residential area and a business district. The study focuses on the central block of buildings covering a total area of 120,200 m 2. The objective of the study is to evaluate main micrometeorological parameters influencing thermal comfort and building energy efficiency in the selected urban scenes; e.g. the wind flow patterns highlight discomfort zones for winter and summer periods. Finally, numerical simulations tools are used to underline the spatial and temporal variability of urban states which makes both difficult the analysis of one urban design and the decision process between several urban cooling strategies. The perspectives to develop new decision support indicators for energy and environmental performance are reviewed and proposed to develop both necessary simulation tools and decision support systems.

International audience; In the context of expansion of cities and raise of climate change awareness, urban planers are looking for methods and tools in order to take into account the urban heat island phenomenon. This study analyzes the way urban fabric modifies urban climate through the utilization of a climate scheme called Local Climate Zone (LCZ). This classification has been applied in Nancy (France). Urban indicators have been calculated so as to build 13 LCZ in the Great Nancy Area. The screen-height air temperature distribution has been investigated inside these LCZ via mobile measurements. Air temperature amplitude has mainly demonstrated lower values at nighttime than in daytime in urbanized LCZ types. Recurrent microscale hotspots and coldspots have been located in LCZ presenting heterogeneous urban fabric. Two Control Sites (CS) have been built in each LCZ. The CS average temperature has revealed good likeness with the spatially averaged air temperature. Average nocturnal air temperature differences between pairs of LCZ types have been obtained. These differences vary from less than 1 degrees degrees C for close LCZ types to more than 4 degrees degrees C for dissimilar LCZ types.

The IPCC fourth assessment report indicates that European cities will be affected by climate changes throughout the 21st century, including heat waves growing more frequent and more intense. The urban heat island (UHI), which is the positive air temperature difference between the city center and the rural areas nearby, can strengthen the negative impact of heat waves in terms of thermal urban comfort, public health and cooling demand of buildings.In order to tackle the issue of climate change adaptation, qualitative information is already available for urban planners. However, most of the existing numerical models require skills and knowledge in urban climatology in order to use them and to analyze their output. Therefore, it is necessary to define new approaches and to produce information in order to evaluate quantitatively the climatic impact of different urban planning proposals. This thesis targeted to study the development possibilities of a climate assessment model designed for urban planning purpose. This work aimed to characterize the UHI phenomenon using high spatial resolution mobile measurements in the urban canopy, performed in the conurbation of Nancy. In order to spatially organize the urban climate analysis, a climatic classification (“Local Climate Zone”, “LCZ”) has been applied. The objective of this scheme is to build homogeneous zones in terms of climatic behavior and urban properties. Within a sample of thirteen zones, seven urban indicators – related to urban morphology and land use – have been calculated. These indicators helped to draw connections between urban areas and LCZ types from the classification. Several mobile measurements campaigns have been performed in the summertime using an instrumented vehicle, in order to observe the climatic patterns of LCZ. The individual analysis has shown homogeneous temperatures within each zone, while the comparison between the zones has highlighted that there are significant air temperature differences during the nighttime. The study of the daily temperature cycle has shown that LCZ behave similarly in the morning and the beginning of the afternoon, and demonstrate a two-phases cooling period during the night. In order to compare the nighttime cooling dynamic over several days, a climatic indicator has been created and correlated with the calculated urban indicators.The combination of LCZ classification and mobile measurements has allowed a detailed analysis of the UHI at various spatial scales. This simplified approach can provide quantitative data, and therefore can be used to develop a new decision-support tool adapted to the urban planners needs.; Le quatrième rapport d’avancement du GIEC (Groupe d’experts Intergouvernemental sur l’Évolution du Climat) indique que les villes européennes seront impactées par des modifications climatiques au cours du XXI siècle, avec notamment avec des épisodes caniculaires plus fréquents et plus intenses. L’îlot de chaleur urbain (ICU), défini comme l’anomalie positive de température d’air existant entre le centre d’une agglomération et les zones rurales environnantes, peut accentuer l’impact néfaste des canicules en matière d’inconfort thermique extérieur voire de risque sanitaire, et decharge de refroidissement des bâtiments.Afin de répondre au défi de l’adaptation au changement climatique, les aménageurs ont principalement accès à une information qualitative présentée sous forme de recommandations et de bonnes pratiques. La plupart des modèles numériques existants, de plus en plus performants, requièrent des connaissances et des compétences en climatologie urbaine pour les mettre en œuvre et analyser leurs sorties. Dans ce contexte, il est nécessaire de proposer aux aménageurs de nouvelles approches, produisant une information adaptée pour évaluer quantitativement l’impact climatique de différentes propositions d’aménagement.Cette thèse avait pour objectif d’étudier la faisabilité du développement d’un modèle de diagnostic climatique mobilisable pour les phases de planification urbaine. Le travail a consisté à caractériser le phénomène d’ICU à partir de mesures mobiles à haute résolution spatiale dans la canopée urbaine sur l’agglomération de Nancy.Dans le but de structurer spatialement l’analyse du climat urbain, une classification climatique (“Local Climate Zone”, “LCZ”) a tout d’abord été appliquée. L’objectif de cette classification est de construire des zones homogènes à la fois du point de vue climatique et du point de vue des caractéristiques urbaines. Au sein d’un échantillon réduit de treize zones, sept indicateurs urbains, relatifs à la morphologie urbaine et à l’occupation du sol, ont été calculés. Ces indicateurs ont permis d’établir des correspondances entre les fragments urbains de l’échantillon et les différentes typologies de la classification LCZ.Par la suite, plusieurs séries de mesures mobiles ont été effectuées en période estivale à l’aide d’un véhicule instrumenté, afin d’observer in situ les spécificités climatiques des LCZ recensées dans l’agglomération. L’analyse individuelle des zones climatiques a révélé que celles-ci sont relativement homogènes du point de vue thermique, particulièrement en période nocturne. La comparaison de l’ensemble des comportements thermiques a indiqué que les différences de température d’air entre LCZ sont significatives en période nocturne. L’étude du cycle journalier de température a permis d’observer que les LCZ présentent des températures d’air proches pendant la matinée et la majeure partie de l’après midi, et connaissent un refroidissement nocturne selon deux phases successives. Dans le but de comparer la dynamique de rafraîchissement nocturne sur plusieurs jours, un indicateur climatique a été proposé, puis mis en relation avec les indicateurs urbains calculés.L’association de la classification LCZ et de mesures mobiles a rendu possible l’analyse détaillée de l’ICU à différentes échelles spatiales. Cette approche “simplifiée” et pédagogique est en mesure de fournir une information quantitative, et peut de ce fait servir de base au développement d’un outil opérationnel de prise en compte du climat local à l’étape de conception du projet urbain.

xi, 76 pages; Many villages in India seem to possess urban characteristics. The Indian definition of urban area is restrictive and excludes numerous localities. This paper consequently explores what is potentially an urban area. A literature review of various definitions of the notion of urban and urbanity enables to develop indicators susceptible to enter a multi-dimensional approach going beyond the census definitions. It suggests a palette of indicators (demographic, social, economic, spatial, infrastructural and administrative) to categorize rural and urban localities. This methodological tool is then applied to a set of eight villages around Bhopal, the capital of Madhya Pradesh. The study identified two types of urban areas, those under the influence of Bhopal (suburban type) and those with a large degree of autonomy (growth-centre type). The results show that even in a sub-metropolitan environment, localities are very diverse and that factors of transformation depend on multiple factors ranging from accessibility and location to situated historical capital. Finally, this working paper demonstrates that studying urbanization only within the Census classified urban local units is certainly limiting and a broader approach may help us better understand the spread of urban characteristics in India even in small settlements and micro agglomerations.

International audience; The decision making process related to urban areas synthetizes a lot of data taking into account numerous parameters. The indicators produced from simulations or data mining on 3D city models (3DCM) can be a great help into these decision-making processes. The problem is to acquire and process the 3DCM in order to produce these indicators at city scale. The EnVIE project proposes a framework to perform the acquisition of 3DCM and then to produce 3D or 2D metadata on these models. As several city councils have been interviewed in the scope of the project to describe their real needs, the computed metadata are directly usable into the decision-making process. The main contribution of this framework is to merge existing techniques to build a pipeline allowing to compute lighting and wind simulation, and to extract socio-economic metadata with data-mining techniques. This on-going work builds a link between indicators at the building scale and 2D indicators at larger scale from GIS, and therefore is a step towards an indicator production process at full-scale range.