POSTER 26: TUKUP - Indicators, climate maps, and decision support tools
Sensitivity of the TEB model to building parameters, urban planning and spatial distributions of natural areas in an urban area. The Paris area example during the 2003 heat wave.
CNRS - Météo France, France
The study investigates the influence of various morphological building parameters (heating and cooling devices, type of wall, roof albedo, etc...), urban planning (city structure distribution) and spatial distributions of natural infrastructures (parks and lakes) on the modelling of the urban climate and urban heat island in the Paris area.
The model used is TEB (Town Energy Balance) developed at Meteo France and the impacts will be quantified by energy consumptions and urban heat reduction.
The technical approach is built on an experimental design, containing all the desired variables based, on latin hypercube sampling.
Analysis of urban flooding from a meteorological perspective applied to two temperate climate cities in Argentina
1UNIVERSIDAD NACIONAL DEL SUR, Argentine Republic; 2National Scientific and Technical Research Council
In urban areas, flooding is considered the main environmental impact of heavy rains. Knowing in advance the synoptic conditions that can generate these types of events might contribute to the mitigation of damage. The city of Bahía Blanca and the coastal town of Ingeniero White, in the southwest of Buenos Aires Province-Argentina, are characterized by a template semi-arid climate. In intermediate seasons, heavy rainfall events usually occurs causing floods over different urban areas. The aim of this work is to map and analyze the effects of rainfall in Bahía Blanca city and Ingeniero White town considering the synoptic conditions that generated the precipitation events in May 2008 - September 2014 period.
Weather conditions were analyzed through synoptic charts published by the National Weather Service and rainfall amounts were measured by means of a network of eleven rain gauges covering both towns. In addition, meteorological data taken from weather stations in Bahia Blanca downtown area and Ingeniero White coastal area were analyzed. To ascertain the effects caused by rainfall in these cities and having previously selected certain areas, the type of impact was assessed once the precipitation event has finished.
Most of the heavy rains events were generated by the convective instability preceding cold fronts that reached the area after warm days. With regard to the effects of such events, the main impact is due to floods not only in flat areas, but also in downtown area when sewer drainage capacity overflows. Besides, these storms affect non-paved streets with steep slope rainfall runoff causing erosive processes which make traffic flow difficult.
Study on future urban form and land use pattern considering urban warming and depopulation -Scenario Making by using concept of potential natural vegetation-
1Hiroshima University, Japan; 2Yokohama National University, Japan
In recent year, thermal environment in urbanized area is becoming severe because of urban heat island and global warming in Japan. This is called urban warming. Consequently, some problems, such as, loss of inhabitant’s comfortable life, increasing of the energy consumption for cooling, extreme weather event and health hazard will occur.
Also, IPCC Working Group I Contribution to AR5 made four RCP scenarios. According to these scenarios, average surface air temperature in the world will increase about one degree Celsius at least by the end of twenty one century.
So, effect of urban warming will become more severe in the future, and mitigation to urban warming considering now and future thermal environment is necessary.
On the other hand, depopulation trend have started recently in Japan. National Institute of Population and Social Security Research estimated that population in Japan will decrease from 128 million to 87 million by 2060. If this depopulation will continue, a ratio of vacant and low-use land in the city area will increase and density of city area will be lower in the future. Consequently, it is said that some problems, such as, deterioration of living environment, decline of local community and increasing of energy consumption per persons, will occur. So new urban form that is adapted to depopulation will be needed in the future.
From these reasons, urban planning have to consider future urban warming and depopulation in Japan and improve thermal environment with shrinking city area and keeping density. However, present urban planning in Japan isn’t made from the view point of urban climate. This reason is climatic phenomena is difficult for people who makes urban planning to understand. So Urban Environmental Climate Maps are made to tell them knowledge of climatic phenomena easily. This map shows the recommendations to improve present environment from present without big changes of urban form and land use pattern. But, if we will change urban form and land use pattern in the future, we have to consider the original climate in area. Specifically, to improve urban warming, cooling potential that originally exist in each area, such as, sea breeze and cold air drainage, should be used.
So urban form and land use pattern that use these potentials as much as possible should be considered with scientific knowledge. And those results should be implemented in urban planning.
Therefore, this study made land use map for Kanagawa Prefecture in case that urban area don’t exist and ground surface is covered with potential natural vegetation. And present land use map is also made from National Land Numerical Information at same time. Then, climate under the potential natural vegetation case and present condition are calculated by using meso-scale meteorological model. Using result in case of potential natural vegetation, authors classify target area into zones from the characteristic of air temperature and wind pattern. As results, climatic map shows the original climatic potentials for each zone is made. On the other hand, present climatic map is also made by the result of present condition by the same way as case of potential natural vegetation. Comparing these two climatic maps, the climatic effect of present urbanization is analyzed and confirm the differences. Then, the proper urban form and land use from the view point of thermal environment is proposed by reducing city area in inadequate environmental urban area in present condition and keeping city area in the area with climatic potential under potential natural vegetation.
Estimation of human-biometeorological conditions in south west Germany for the assessment of mitigation and adaptation potential
Albert-Ludwigs University Freiburg, Germany
Human thermal perception is influenced by a lot of meteorological parameters. The parameters showing the strongest impact on thermal biometeorology, especially during summer conditions, are the different radiation fluxes, as well as the local wind field. Both are strongly dependent on the surrounding environment resp. urban morphology. Therefore, they can be modified by urban planning. Radiation in urban structures is modified by shading, changes in surface material and the configuration of structures (aspect ratio, orientation). The modification of the local wind field by urban structures is more complex. Obstacles can cause stagnation that lowers wind speed. Others might cause a recirculation or lead to wind channeling that increases wind speed.
The impact of the single meteorological parameters on thermal bioclimate can be best estimated by applying thermal indices, e.g. the perceived temperature (PT), the universal thermal climate index (UTCI) or the physiologically equivalent temperature (PET). To assess thermal stress for humans, the results can be evaluated using the thermal stress classifications, that are available for different indices and regions.
In the course of the KLIMOPASS project, the thermal indices PT, PET and UTCI have been calculated for five mid-sized to large cities in Baden-Wuerttemberg (South-West Germany). For each city thermal bioclimate was estimated to determine the current state conditions based on long term climate data. To get an insight on future conditions, the three thermal indices have also been calculated based on data generated by regional climate models. Analysis of the results has been performed annually, seasonally, as well as for day and night patterns. Additionally the average hourly distribution of the indices over the year was estimated.
To be able to predict the modification of thermal bioclimate by changes in urban morphology, the sensitivity of the indices to changes in the most important meteorological input parameters air temperature (Ta), air humdidity (RH or VP), wind speed (v), and mean radiant temperature (Tmrt) should be known. Especially modifications in Tmrt and v seem to be quite promising in terms of influencing urban thermal bioclimate. Both parameters are strongly driven by the urban morphology and can therefore be easily influenced by urban planning measures. Tmrt and v also show strong influence on heat stress for humans.
Knowledge and technological transfer: a user-friendly multi-model platform for consulting services to simulate the evolution of the city and the urban climate over a century, from a prototype developed within the multidisciplinary project ACCLIMAT
1Météo-France, France; 2Cerfacs, France
In the recent years consulting services have seen a rapid growth of requests in the field of urban climate. These requests generally concern the assessment of
· the vulnerability of urban areas, particularly those facing heat waves, or in a context of climate change,
· urban planning policies, with their impacts on climate and energy consumption,
· hydrological risks in urban areas (flash-floods, rainwater and wastewater sewer system, shrinkage of soils during droughts).
The main challenges in conducting industrial and commercial studies include:
· the case-by-case treatment du to the heterogeneity of the requests,
· the gathering of homogeneous urban descriptive information,
· the use of meteorological models,
· the transcription of the scenarios of urban planning developed by the partners.
This paper aims at presenting the steps, the methods, the hypotheses and the support which were implemented to overcome these barriers and to offer a user-friendly multi-model platform to simulate the evolution of the city and the urban climate over a century.
These actions have been led
· by capitalizing on the works of the National Center for Meteorological Research (CNRM) in the field of urban heat island through a prototype developed within the multidisciplinary project ACCLIMAT (Adaptation au Changement CLIMatique de l’Agglomération Toulousaine);
· leaning on a knowledge transfer structure,
· by expanding the current capacities of the prototype: cover of other territories, other resolutions, multi-users, remote access, modular by type of study, new meteorological data sets or climatic projections,
· by setting up a team in charge of the integration and adaptation of the platform, a support team, and organizational arrangements to take into account future developments of the models making up the platform.
Expected or already estimated gains in terms of human resources involved in urban climate study when using this new platform will be presented.
The simplifications brought to the prototype will be tested on the city of Toulouse and will be assessed on some key indicators and systemic scenarios inherited from ACCLIMAT.
A Climate Adaption Concept for the Urban Heat Island
1RWTH Aachen University, Germany; 2BKR Aachen Noky & Simon, Germany
Climate adaption concepts are presently being developed or prepared for numerous cities. Data basis and implementation in urban development vary in a wide range. The concept presented in this study includes a data capture and monitoring strategy as well as a geostatistical analysis tool which allows for the localisation of core areas of urban heat islands and for quantification of possible mitigation measures. Based on these data, recommendations for the implementation of mitigation strategies in urban planning can be formulated at different spatial and organisational levels.
Many cities do either possess insufficient or, due to current urban development, outdated data on intensity and position of the urban heat island. Therefore, a simple but easy to apply measurement strategy has been developed especially for the needs of planning related to heat island analysis. Mobile sensors for temperature, relative humidity and solar radiation – combined with a GPS device – are used on vehicles following predefined or random tracks, recording data over longer periods or during selected weather situations. The data is related to simultaneously recorded data from a meteorological reference station which allows for combination of the mobile short-term data with temperature time series.
The spatial data evaluation is based on a geostatistical analysis using a multiple linear regression approach to analyse and quantify the relationship between urban temperatures and land use represented by high resolution land use data. Both remote sensing and cadastral data can be used. It proved to be useful to extract temperature and land use data for fixed points along the tracks of mobile data acquisition. By this means we simulate a network of station sites. Depending on the type of land use data, urban structure, weather situation or daytime, correlation coefficients and number and structure of predictors vary. Typical predictors with acceptable correlation coefficients are the green fraction and the built up area fraction. Close relationships are rather to be found in the evening than during daytime. Useful footprints of about 500 m to 1000 m resulted from the analysis of data obtained for the cities of Aachen and Münster in northwest Germany. The resulting multiple geostatistical model explains up to 82% of the variance in two urban case studies.
The model can be used to visualise the systematical effects of urban structures on the actual urban heat island. It also allows for quantifying possible effects of mitigating measures like additional greening. The measurements can be repeated as part of a monitoring concept to verify the success of implemented measures.
The concept has been developed for the City of Aachen in a cooperation of the Department of Geography of RWTH Aachen University and the private planning office BKR Aachen Noky & Simon. A main part of the study is a communication concept to contribute to improved awareness and acceptance for climate change related urban development strategies especially within the city administration but also within the general public. Aachen is one of the first German cities to implement climate change related issues into a preparatory land-use plan according to the regulations of the new federal building code which now explicitly names climate change related concerns to be considered in legal decisions and coming projects of urban development.
This work is partly funded by the German Federal and State Governments through the German Research Foundation’s Excellence Initiative within the project Urban Future Outline (UFO) as part of the Human Technology Centre (HumTec) at RWTH Aachen University. Furthermore, the data acquisition strategy using mobile instrumentation has partly been developed within the European Institute of Technology Climate Knowledge and Innovation Centre’s (Climate KIC) project “Urban Mobile Measurements for Environmental Monitoring” (URBMOBI).
The utilization of first derivatives and violinplots of meteorological parameters for the evaluation of thermal behavior of small urban sites.
1Lab. of General and Agricultural Meteorology, Agricultural University of Athens, Greece; 2Albert-Ludiwgs-University Freiburg, Germany
Human thermal comfort in the urban environment is influenced by meteorological and additionally by urban geometrical and distribution parameters of structures. In this context, vegetation is recognized as an important and effective measure to mitigate high thermal stress and to improve thermal comfort in the urban environment. Also, vegetation is one of the simplest and most effective ways to improve thermal conditions and reduce energy demanding. First, one important characteristic of the vegetation, in terms of microclimatic alteration, is its ability to cool the adjacent environment via shading and evapotranspiration function. Moreover, the vegetation structure type (park, courtyard, forest etc) is a substantial factor for beneficially influencing the atmospheric conditions. Also the vegetation’s type, like tree, shrub or ground grass is a key factor for the heat stress.
The most common way to present the thermal behavior of urban sites is the illustration via daily courses of significant parameters such as air temperature, mean radiant temperature and indices such as physiologically equivalent temperature etc. In addition the frequency classes’ diagrams or the boxplots presenting the aforementioned parameters are widely used. In order to analyze thoroughly the bioclimatic behavior of the urban sites the utilization of the first derivative of fundamental meteorological – thermal parameters were presented. Moreover the graphic representation of the violinplot is able to make more comprehensive the frequency distribution of the selected paremeters.
The present study is introducing the usage of first derivative of the temperature (∆Ta/∆t), the mean radiant temperature (∆Tmrt/∆t) and the physiologically equivalent temperature (∆PET/∆t) along with the respective violinplots. The above “tools” were implemented in the case study of five small urban sites which differ on geometric configuration and the materials (vegetation, concrete etc). The cooling/heating process was investigated during summer and winter period.
The results demonstrated clearly the interpretative aptitude of the first derivative’s parameters. The violinplot has proved as a reliable tool to visualize related information to the bioclimatic behavior of outdoor spaces and, in general, various environmental configurations. Additionally the results of the present study demonstrate the striking influence of the vegetation and the geometric characteristics (SVF) on the thermal regime and the biometeorological condition.
Urban climate and heat-stress patterns in Berlin, Germany
Technische Universität Berlin, Germany
The combined effects of climatic and demographic change increase the vulnerability of city dwellers towards heat-related stress. In order to reduce heat-stress risk, the specifics of urban climate have to be addressed in relation to the urban environment on the small-scale level. Accordingly, urban heat island (UHI) effects and population aging must be studied in a coherent and spatially explicit manner considering the increasing frequency of extreme heat events. This paper pursues two objectives: 1. identifying the effects of urban structural patterns and land use on urban climate at two different times of day by applying several descriptive indicators of the urban environment, and 2. identifying areas at potential risk towards heat stress based on social vulnerability at night when the adaptive capacity of the city dweller is very low. In the first part, we use landscape metrics, urban structure parameters, statistical and GIS analysis to show how surface urban heat island (SUHI) is influenced by land use composition and structural patterns. Using multiple regressions we obtained the degree of soil sealing to be the best predictor of land surface temperature (LST). However, under specific conditions, NDVI, distance to city center and Floor area ratio (FAR) are better able to explain LST variations. Results show that water bodies have beneficial effects at daytime with inverse effects in the evening. With arable land it behaves exactly opposite. The cooling effect of urban green spaces and forests is more significant in the morning than in the evening. Residential uses are among the most affected ones at 10pm, with different intensities according to their density level. In the second part we introduce a matrix to assess heat-stress risk on the building scale by combining simulated air temperature data with socio-demographic data. Results show that beside the higher potential risk in dense residential uses of the inner-city there are some unexpected lower potential risks. The identified building blocks can provide urban planners with useful information in order to mitigate adverse effects caused by future heat waves.
WAsP software - application for data analysis of wind over a city
1Universidade de São Paulo/Brazil; 2Universidade de Lisboa/Portugal
The paper presents an analysis on how wind and large urban areas can interact. Large cities can be thought as included in two different groups on its genesis: old and new cities. The first group can typically be defined from an old settlement (some centuries) that must present conditions related not only with the comfort but also with the safety (defence) of the neighbouring populations. The second group includes the more recent cities (a couple of centuries of history) settled in conditions where defence is not a mandatory condition. For the first ones the nucleus is “old”, normally in hilly and slopy terrain, and their expansion along the centuries is made occupying the farm lands (plain terrain) around that nucleus; the new cities were as a rule established in plain terrain normally with hilly boundaries that are now being invaded by the urban expansion. Both of them have a common background that supports their settlement and development along time: they need water and good air quality. In what concerns this last aspect we now know that man does not like to settle in places where mean yearly wind velocities are above 5 to 5.5 m/s and the standard deviation is low (above 25%- 30% of the mean velocity).
A methodology and procedures are defined, based on the use of a software tool currently applied in Wind Power Assessment (WAsP) of a site. An application is presented for a large city, Campinas, in São Paulo, Brazil. Thus Campinas is a city typical of the second group defined previously (established in the plain as a small nucleus and then growing, occupying the involving hilly - soft slopes - terrain). The Master Plan divides the city in nine macrozones. These were created due to the heterogeneity of the areas of the city of Campinas and their definition took into consideration physical-territorial, socio-economic and environmental aspects.
Results obtained clearly support and justify more conventional descriptions of the area climate (identification of large scale atmospheric flows) and provide a separation of local topographic effects (reproduced by isolevel lines 10m apart) from those induced by the city itself (considered as a single roughness variance of the terrain in a first approach). At the same time they give a fair indication of what are local effects associated with details in the urban structure as wind data from 3 different meteorological stations, corresponding to a common period, extending for about 10 years was collected, treated and compared.
Another way of looking at the city from the perspective of ventilation in urban environment is to analyze its influence on the extreme conditions of climate events occurring in the city. Maps for the city’s regions were developed based on data from Defesa Civil and on distribution of the Macrozones, highlighting the percentage of occurrence of events registered as falling of trees or branches and houses / edifices de-roofed or otherwise affected by the wind (Codar, NE.EVD). It is, thus, possible to pinpoint the areas where these events are observed more often, and to confront them with the wind maps obtained with the WAsP software.
The use of this software in the analysis of natural ventilation in an urban environment aids in the planning and organization of the territory, where climate issues should be discussed and analysed in scales which extrapolate the city limits and should – thus – be an integral part of the planning of mega-metropoles or metropolitan areas. The dispersion of pollutants and/or the quality of the air could be better addressed if we thought of our cities with base on climate and environmental variables.
Urban climate and materials properties: What do we know about this field? How can we use this knowledge for urban planning? How can we adapt and better build our cities for tomorrow?
Surface materials properties play an important role in the modification of local climate over urban areas. This means that a reflection on materials used in urban design is one of the pertinent means of adaptation to the increase of temperature during strong urban heat islands and heat waves events.
The role of urban materials properties on climate adaptation is less known by urban stakeholders and practitioners than for example the introduction of water or vegetation. This study aims to synthesize what do we know about this field (focusing on materials used on roofs, facades and pavements) and what are the means and the channels in France to transfer it to the practitioners that decides what kind of materials are being used in a particular urban planning.
The research questions addressed will be: What is the role of materials properties in the modification of urban climate compared to other physical factors (for example with the ratio of natural surfaces vs. artificial surfaces or with roughness)? Which are the materials the most efficient? Which are the new materials produced with the objective to counter the increase of urban temperature? Who are the actors on this market? Which are the criteria permitting to choose the best material in a particular case ? What could be done for the constructions that are already built? What are the feedbacks of the experimental buildings used par researchers, and how can these feedbacks be transferred to the practitioners of urban and design planning? What is the visibility that we have about this field and how could we progress?
Countermeasure guidelines and evaluation tools against heat island phenomena for several cities in Japan and East Asia
1University of Fukui, Japan; 2Taisei Corporation; 3Kobe University; 4Hiroshima University; 5Tohoku University; 6IIS, The University of Tokyo; 7Tokyo Polytechnic University; 8South China University of Technology
In this paper, we introduce activities of a working group entitled “Working group for investigating countermeasure guideline against urban heat island of each city in East Asia”. This group has been established in the sub-committee on urban and climate adaptation, research committee on global environment, AIJ, since 2012. The objective of the working group is to propose a countermeasure guideline against urban heat island of each city in East Asia as well as to investigate differences between each existing guideline against the heat island of several cities in Japan and China. In the former part of this paper, we outline existing countermeasure guidelines for urban heat island in Japan, Japanese local governments, and East Asia countries, while we investigate detail comparison of targets and countermeasure menus included in each countermeasure guideline in Japanese local government in the latter part of this paper. Through the investigation and the comparison, it has been found that there is a large difference of the space length scale that is affected by the countermeasure menus between each guideline, although the difference of the objective between each guideline is relatively small.