Modelling co-designed geoprospective scenarios to assess greening adaptation strategies at the metropolitan scale

Urban green planning in Europe is of crucial importance for the sustainability of cities. Despite the existence of numerous best practices, in Italy the integration between green plans and urban planning tools still presents difficulties. This study focused on an analysis of Italian case studies that have engaged in innovative urban planning, assigning green areas a strategic role in the development of cities. The comparative analysis involved the green plans of Torino and Bolzano and the local urban plans of Prato and Bologna. The selection of cases was based on a multifaceted evaluation framework encompassing reference regulatory context, plan nature, environmental characterisation, vision and main objectives, priorities and implementation tools, communication and participation, and monitoring and management. Analysis of these case studies led to the identification of best practices for integrating human and environmental dimensions in local urban planning. However, the results indicate that integration of urban greening and local planning policies is frequently impeded by regulatory discrepancies and the varying impact capabilities of urban planning instruments. Despite the limited nature of the sample analysed, the study proposes a model of synergy between urban greening and local planning, suggesting an opportunity to create innovative interpretative and evaluative criteria for regulatory plans.

Making the case for gardens: Estimating the contribution of urban gardens to habitat provision and connectivity based on hedgehogs (Erinaceus europaeus)

Abstract. In winter, snow- and ice-covered artificial surfaces are important aspects of the urban climate and trigger road maintenance operations. Urban climate and road weather models have specialized in simulating these conditions in cities or in the countryside, respectively. In this study, we intend to bridge the gap between road weather models and urban climate models in terms of cold region urban modelling and artificial surface condition predictions in any environment. We have refined the modelling of road surface processes related to winter conditions in the Town Energy Balance (TEB), an urban climate model designed for complex environments. We have developed an ice content prediction to account for the freezing and melting of the water content on the surface. Additionally, we have enhanced the TEB representation of snow on road, moving from a single-layer snow model (1-L), to a more precise multi-layer snow model known as Explicit Snow (ES). We have isolated the winter surface processes from other physical interactions by limiting the evaluation of the experiments to open environments. The experiments are carried out at two locations: the Col de Porte in the Alps and a road weather station in southern Finland. Our findings show that the enhanced TEB model (named TEB-ES) outperforms TEB, as well as a benchmark model, ISBA-Route/CROCUS, but with mixed results against a multiple linear regression in-sample algorithm. For roads with high traffic and/or winter maintenance operations, future modelling work should focus on the representation of anthropic effects.

Cities are rapidly growing. There is an assumption that 90% of global population growth will be in cities between now and 2030. Therefore, infrastructures and the environment have to be adapted to the changing demands. Moreover, new urban development strategies have to be elaborated. In 2007, the first international Visualization Summit of more than 100 international researchers and practitioners stated a jointly developed research goal for the year 2010, namely ’Visualizing Future Cities’. Therefore in this chapter we provide an overview about visualization methods, decision support tools in architecture, urban and regional planning, stakeholder participation and collaborative environments. Also, new decision support tools for the visualization of future cities will be introduced.

The computer‐based GIS, with its remarkable ability to store, retrieve, manipulate and display vast quantities of spatial and attribute data, has become a very useful tool for urban planning. Yet the utility of GIS in urban planning and management is often hampered by a lack of current and sequential land‐cover and land use information. This is because most of the geographic information that is input to a GIS must be obtained from out‐dated maps. This problem could be overcome by satellite remote sensing technologies, such as the Landsat Thematic Mapper (TM) and the SPOT High Resolution Visible (HRV), which are very useful for gathering land use and land cover information. However, satellite remote sensing techniques applied to land‐cover classification and land‐use mapping remain largely experimental since current per‐pixel multispectral algorithms are incapable of producing the requisite accuracy for urban and local planning. This paper discusses a relatively simple but accurate automated land‐cover and land‐use classification technique using a microcomputer‐based image analysis and geographic information system. Results obtained with this technique suggest that the integration of GIS capabilities and image analysis techniques can improve significantly the conventional multispectral classification procedure.

In order to mitigate the impacts of climate change in urban areas, there is a growing emphasis on the promotion of nature-based solutions (NBS) with expected benefits for biodiversity, rainwater management, evaporative cooling, and carbon sequestration. Among the various possible NBS, green facades have the advantage of being deployable in already built area. The environmental evaluation of greening policies through the implementation of green facades requires integrated physical-based numerical model to simulate radiative, energy, and carbon exchange processes at building scale but within a modelling framework that can also address interactions at the neighbourhood and city level.Here, the urban canopy model Town Energy Balance (TEB, Masson, 2000) is revised with the implementation of a new green façade module informed with micrometeorological and ecophysiological observations collected on an experimental green façade site located in Berlin, Germany (Hölscher et al, 2016). The first step is the improvement of short- and long-wave radiative exchanges in TEB by considering an additional vegetation layer fixed to the wall. We now take into account the processes of interception of radiation by the vegetated layer, of transmission through it (depending of leaf density), and of absorption, as well as the inter-reflections within the canyon including new contributions from green façade.First results show that the model is able to represent the effect of the vegetation foliage and its evolution on the radiative balance. This constitutes the first step in achieving the fully integrated modelling of the impact of green façades on the urban climate in TEB. Reference :Hölscher, M.-T., Nehls, T., Jänicke, B. and Wessolek, G., 2016. Quantifying cooling effects of facade greening: Shading, transpiration and insulation. Energy and Buildings, 114: 283–290. Masson, V., 2000. A physically-based scheme for the urban energy budget in atmospheric models. Boundary-Layer Meteorology 94: 357–397.

Urban surface effects on current and future climate

In Finland, based on the Land Use and Building Act, the city has a monopoly in urban planning and design. Through the planning monopoly, the city manages the urban planning process and thus consciously develops the urban structure. Based on the Act, the number of parking spaces stipulated for the property in the local detailed plan and building permit must be provided in connection with the construction work. The obligation of providing a number of parking spaces stipulated in local detailed plans affects the society in many ways. The provision of parking spaces is a key economic factor in construction costs. Car parking is also linked to changes in people’s mobility habits and car ownership. Occupancy rates for obligation parking spaces and other parking spaces vary over time and location. Car parking also impacts urban flood management. Rainwater volumes in condense urban structure can be significant and require heavy technical stormwater management solutions. Urban design is a key action of a city’s competence in terms of preparing for future changes. The number of parking spaces and stormwater management are key tools in urban planning that can be used to define resilience in the northern context of urban planning.

While capabilities in urban climate modeling have substantially increased in recent decades, the interdependency of changes in environmental surface properties and human (dis)comfort have only recently received attention. The open-source solar long-wave environmental irradiance geometry (SOLWEIG) model is one of the state-of-the-art models frequently used for urban (micro-)climatic studies. Here, we present updated calculation schemes for SOLWEIG allowing the improved prediction of surface temperatures (wall and ground). We illustrate that parameterizations based on measurements of global radiation on a south-facing vertical plane obtain better results compared to those based on solar elevation. Due to the limited number of ground surface temperature parameterizations in SOLWEIG, we implement the two-layer force-restore method for calculating ground temperature for various soil conditions. To characterize changes in urban canyon air temperature (Tcan), we couple the calculation method as used in the Town Energy Balance (TEB) model. Comparison of model results and observations (obtained during field campaigns) indicates a good agreement between modeled and measured Tcan, with an explained variance of R2 = 0.99. Finally, we implement an energy balance model for vertically mounted PV modules to contrast different urban surface properties. Specifically, we consider (i) an environment comprising dark asphalt and a glass facade and (ii) an environment comprising bright concrete and a PV facade. The model results show a substantially decreased Tcan (by up to − 1.65°C) for the latter case, indicating the potential of partially reducing/mitigating urban heat island effects.

Urban areas are particularly affected by climate change due to continuing urban development and an increased occurrence of extreme weather events like heat waves that lead to increasing heat stress on urban population. Furthermore, the occurrence of heavy rain events and dry periods are expected to rise, posing additional challenges to cities because sealed surfaces inhibit the infiltration of water into the soil and thus increase storm water runoff and reduce the water availability for plants. The project GreenAdaptation, funded by the Austrian Climate Research Program (ACRP), examines crucial steps necessary to support climate change adaptation and to develop urban planning recommendation and climate analysis maps for cities and municipalities, as they provide an important tool to support urban planners and local administrations towards decision making and to facilitate future urban planning processes. Urban climate analyses represent an essential component in the development of urban planning recommendation maps. Here, we focus on already existing climatological datasets as well as urban climate modelling tools. To gather pre-existing knowledge regarding temperature and precipitation change, a set of climate indices with respect to heat, heavy rainfall and drought are selected together with practitioners implementing adaptation measures. The climate indices are calculated using available observational datasets from the Austrian semi-automatic meteorological station network (TAWES) and Austrian climate scenarios (OEKS15) to assess the past and indicate future development for the chosen municipality. Urban climate simulations carried out by the urban climate model MUKLIMO_3, developed by DWD (German Meteorological Service), are used to analyze overheating and to identify areas particularly affected by heat, taking into account city-specific structures and land use information, as well as meteorological conditions. Furthermore, a digital elevation model is analyzed to identify areas potentially prone to flooding. Merging the derived maps will indicate critical zones prone to extreme weather impacts, but also areas with a high synergy potential for climate adaptation. The methodological framework for the consolidation and integration of the analyses into urban planning recommendation maps will be demonstrated and results of the urban climate analysis will be shown for the Municipality of Perchtoldsdorf, Lower Austria.

Abstract. The Town Energy Balance (TEB) model has been refined and improved in order to explicitly represent street trees and their impacts on radiative transfer: a new vegetated stratum on the vertical plane, which can shade the road, the walls, and the low vegetation has been added. This modification led to more complex radiative calculations, but has been done with a concern to preserve a certain level of simplicity and to limit the number of new input parameters for TEB to the cover fraction of trees, the mean height of trunks and trees, their specific leaf area index, and albedo. Indeed, the model is designed to be run over whole cities, for which it can simulate the local climatic variability related to urban landscape heterogeneity at the neighborhood scale. This means that computing times must be acceptable, and that input urban data must be available or easy to define. This simplified characterization of high vegetation necessarily induces some uncertainties in terms of the solar radiative exchanges, as quantified by comparison of TEB with a high-spatial-resolution solar enlightenment model (SOLENE). On the basis of an idealized geometry of an urban canyon with various vegetation layouts, TEB is evaluated regarding the total shortwave radiation flux absorbed by the elements that compose the canyon. TEB simulations in summer gathered best scores for all configurations and surfaces considered, which is precisely the most relevant season to assess the cooling effect of deciduous trees under temperate climate. Mean absolute differences and biases of 6.03 and +3.50 W m−2 for road, respectively, and of 3.38 and +2.80 W m−2 for walls have been recorded in vegetationless canyons. In view of the important incident radiation flux, exceeding 1000 W m−2 at solar noon, the mean absolute percentage differences of 3 % for both surfaces remain moderate. Concerning the vegetated canyons, we noted a high variability of statistical scores depending on the vegetation layout. The greater uncertainties are found for the solar radiation fluxes received and absorbed by the high vegetation. The mean absolute differences averaged over the vegetation configurations during summertime are 21.12 ± 13.39 W m−2 or 20.92 ± 10.87 % of mean absolute percentage differences for the total shortwave absorption, but these scores are associated with acceptable biases: −15.96 ± 15.93 W m−2.

The Town Energy Balance (TEB) model of Masson simulates turbulent fluxes for urban areas. It is forced with atmospheric data and radiation recorded above roof level and incorporates detailed representations of the urban surface (canyon geometry) to simulate energy balances for walls, roads, and roofs. Here the authors evaluate TEB using directly measured surface temperatures and local-scale energy balance and radiation fluxes for two `simple' urban sites: a downtown area within the historic core of Mexico City, Mexico (stone buildings five to six stories in height), and a light industrial site in Vancouver, British Columbia, Canada (flat-roofed, single-story warehouses). At both sites, vegetation cover is less than 5%, which permits direct evaluation of TEB in the absence of a coupled vegetation scheme. Following small modifications to TEB, notably to the aerodynamic resistance formulations, the model is shown to perform well overall. In Mexico City, with deep urban canyons and stone walls, almost two-thirds of the net radiation is partitioned into storage heat flux during the day, and this maintains large heat releases and an upward turbulent sensible heat flux at night. TEB simulates all of these features well. At both sites TEB correctly simulates the net radiation, surface temperatures, and the partitioning between the turbulent and storage heat fluxes. The composite wall temperature simulated by TEB is close to the average of the four measured wall temperatures. A sensitivity analysis of model parameters shows TEB is fairly robust; for the conditions considered here, TEB is most sensitive to roof characteristics and incoming solar radiation.

In light of the growing global environmental challenges, smart cities need to serve as testing workshops or labs to smartly tackle complex cross-sectional issues like jobs, seamless mobility, safety and security, sustained growth, while responding to the impending climate change too. This necessitates for developing a smart model or tool that integrates such varied but crucial climate concerns of a city into its direct decision-making and long-term planning. In this research, we conduct a literature review to have an overview of the state-of-the-affairs on urban climate planning in Asia-Pacific Cities covering China, Japan, India, Philippines, Singapore and Thailand. This is followed by an intensive theoretical understanding on the need of having a smart tool in urban climate action planning. This includes the study of recent urban climate metrics and tools, their different typologies based on key purpose, method, sectoral and geographical scope, and challenges and gaps in formulating smart urban climate tools. We then introduce the conceptual framework for integrated climate action planning (ICLAP) tool that transects spatial, statistical and bibliometric methods. We establish applicability of ICLAP in case of Indian cities by discerning climate vulnerabilities, GHG trends and relevant urban climate solutions. The paper eventually culminates with major scientific findings and policy recommendations, essentially underscoring more intensive and wider application of ICLAP like smart urban climate tools in local decision making and national urban policies duly supported by international scientific collaborations.

Evaluation of the Urban Heat Island of 12 cities of France in a high-resolution regional climate model simulation

Abstract. The paper describes the implementation of the 3D city model of the pedestrian area of Cosenza, which in recent years has become the Bilotti Open Air Museum (MAB). For this purpose were used both the data available (regional technical map, city maps, orthophotos) and acquired through several surveys of buildings and "Corso Mazzini" street (photos, topographic measurements, laser scanner point clouds). In addition to the urban scale model, the survey of the statues of the MAB was carried out. By means of data processing, the models of the same statues have been created, that can be used as objects within the city model. The 3D model of the MAB open air museum has been used to implement a Web-GIS allowing the citizen's participation, understanding and suggestions. The 3D city model is intended as a new tool for urban planning, therefore it has been used both for representing the current situation of the MAB and for design purposes, by acknowledging suggestions regarding a possible different location of the statues and a new way to enjoy the museum.