Last year sessions ITS6.1-3 on urban geosciences have largely confirmed the urgency to develop inter-/trans-disciplinary approaches of urban geosciences to respond to the huge societal demand to radically improve urban systems and their interactions with their environment and climate. The session ITS.6.1 focussed on the need to develop holistic approaches going beyond specialised domains such as urban meteorology, hydrology, climatology, ecology and resilience to grasp the urban-geophysical systems in their multi-component and multiscale complexity. This in particular indispensable to resolve long lasting questions like multi-hazard threats and upscaling of climate solutions. The recent IPCC report 1.5°C confirms the necessity to fully take into account the multi-component complexity of the urban-geophysical systems to achieve the urban and infrastructure transition, one of the main four system transitions to be achieved

The present session calls therefore for contributions on the development transdisciplinary concepts, methodologies and tools, as well as their applications to urban-geophysical systems in view of this transition. Jean Jouzel (former IPCC vice-president) will open this session.

Public information:
ITS2.10 invites you to actively participate (audio and/or pdf slide sharing) to the Great Debate: "Epidemics, Urban Systems and Geosciences"
Monday 4 May, 12:30-14:00 ECT
e-room COVID-19 https://vmi270945.contaboserver.net/b/pau-guy-rwr
(no app to upload, just click on this link).

This debate is focused on a major upset of the geosciences agenda, particularly those dealing with urban systems so that they contribute more to well-being and health. This great debate will be an opportunity to take stock and open up perspectives, particularly on epidemics and mobility, the dynamics of Covid-19, cities, health and geosciences

Do not miss the opportunity to e-debate with:
Theo Geisel (Max Planck Institute, Göttingen)
Jacques Demongeot (Université Grenoble Alpes)
Mark J. Nieuwenhuijsen (Institute for Global Health, Barcelona)

This debate is a follow-up of ITS2.10 and is organised with the UNESCO UniTwin CS-DC (Complex Systems Digital Campus).

Co-organized by CL3/ERE7/HS12, co-sponsored by AGU and JpGU
Convener: Daniel Schertzer | Co-conveners: Matthias Demuzere, Klaus Fraedrich, Gabriele ManoliECSECS, Stefano Tinti
| Mon, 04 May, 10:45–12:30 (CEST)

Files for download

Download all presentations (46MB)

Chat time: Monday, 4 May 2020, 10:45–12:30

Chairperson: Daniel Schertzer, Klaus Fraedrich, Gabriele Manoli
D2583 |
Gaby Langendijk, Diana Rechid, and Daniela Jacob

Urban areas are prone to climate change impacts. A transition towards sustainable urban systems is relying heavily on useful, evidence-based climate information on urban scales. 

However, many of the urban climate models and regional climate models are currently either not scale compliant for cities, or do not cover essential parameters and/or urban-rural interactions under climate change conditions. Furthermore, although e.g. the urban heat island may be better understood, other phenomena, such as moisture change, are little researched. Our research shows the potential of regional climate models, within the EURO-CORDEX framework, to provide climate information on urban scales for 11km and 3km grid size. The city of Berlin is taken as a case-study. The results show that the regional climate models simulate a difference between Berlin and its surroundings for temperature and humidity related variables. There is an increasing urban dry island in Berlin towards the end of the century, as well as an increasing urban heat island. The study shows the potential of regional climate models to provide climate change information on urban scales.

For climate information to underpin the urban transition this information will need to be put in a decision-making context. As an example, the research aims to understand connections to the health sector on how to integrate the information in order to manage e.g. the dispersion of pollen in cities, assisting in mitigating pollen allergies. The research showcases an interdisciplinary way forward to firstly produce climate information on urban scales and secondly how to connect it to city sectors in a suitable manner to underpin the transition to sustainable urban systems. 


How to cite: Langendijk, G., Rechid, D., and Jacob, D.: The role of climate information for the urban transition towards sustainability , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20466, https://doi.org/10.5194/egusphere-egu2020-20466, 2020

D2584 |
| Highlight
Ye Tian, Klaus Fraedrich, and Feng Ma

Extreme events such as heat waves occurred in urban have a large influence on human life due to population density. For urban areas, the urban heat island effect could further exacerbate the heat stress of heat waves. Meanwhile, the global climate change over the last few decades has changed the pattern and spatial distribution of local-scale extreme events. Commonly used climate models could capture broad-scale spatial changes in climate phenomena, but representing extreme events on local scales requires data with finer resolution. Here we present a deep learning based downscaling method to capture the localized near surface temperature features from climate models in the Coupled Model Intercomparison Project 6 (CMIP6) framework. The downscaling is based on super-resolution image processing methods which could build relationships between coarse and fine resolution. This downscaling framework will then be applied to future emission scenarios over the period 2030 to 2100. The influence of future climate change on the occurrence of heat waves in urban and its interaction with urban heat island effect for ten most densely populated cities in China are studied. The heat waves are defined based on air temperature and the urban heat island is measured by the urban-rural difference in 2m-height air temperature. Improvements in data resolution enhanced the utility for assessing the surface air temperature record. Comparisons of urban heat waves from multiple climate models suggest that near-surface temperature trends and heat island effects are greatly affected by global warming. High resolution climate data offer the potential for further assessment of worldwide urban warming influences.

How to cite: Tian, Y., Fraedrich, K., and Ma, F.: Analysis of heat wave features and urban heat island effect under climate change, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20805, https://doi.org/10.5194/egusphere-egu2020-20805, 2020

D2585 |
Sascha Hokamp, Sven Rühe, and Jürgen Scheffran

The goal of environmental exposure modelling is to link fundamental human activities with stress via the environment. Stress is here defined as environmental conditions negatively affecting human health and well-being. Especially in urban areas, humans can be exposed to multiple stressors such as air pollution, noise (e.g. traffic), and heat. The importance of being able to predict the exposure level in urban areas is increasing due to ongoing urbanization and global climate change. For instance, in Germany annual Greenhouse Gas (GHG) emissions have been reduced by 28% from 1990 to 2014 but contributions by the transport sector have been quite stable (from 0.163 GtCO2Equivalents in 1990 to 0.160 GtCO2Equivalents in 2014 (Umweltbundesamt, 2016). Yang et al. (2018) provides a stylized agent-based model of human exposure to environmental stressors (heat, rain, NO2) for Hamburg, Germany. Within this ABM, the changing exposure to environmental stressors is analyzed for citizens as a function of time and location. The population is classified into different archetypes; they range from young, single students to families with children to old, rich and single persons. While their choice of transportation is a function of exposure, commuting time and costs, each agent has different preferences and different rates to adapt to changing environmental conditions. The agents are moving in multiple layers of housing (e.g. residential buildings) and infrastructure (e.g. streets, subway). Depending on the agent types, bike, car or public transport is chosen as the preferred mean of transport. However, Yang et al. (2018) consider stylized agent-based dynamics without any interaction among the agents. We provide a multi-agent docking study of human exposure to environmental stressors implemented in Netlogo and find distributional and relational equivalence (Axtell et al., 1996, Hokamp et al. 2018) to Yang et al. (2018). To put it differently, we analyze interacting individual heterogeneous agents in an actual urban environment. Results give information about the mean of transportation with the lowest exposure and how very low costs for public transport affect choices of transportation and so the road traffic. Further, the results may be used by policy makers and citizens (e.g. via mobile devices using an app) to improve environmental quality of life.


Axtell, R., Axelrod, R., Epstein, J.M., and Cohen, M.D. (1996) Aligning simulation models: a case study and results. Computational & Mathematical Organization Theory, 1 (2), 123–141.

Hokamp, S., Gulyas, L., Koehler, M. and Wijesinghe, S. (2018), Agent-based Modelling and Tax Evasion: Theory and Application, 3-35, Hoboken, NJ, John Wiley & Sons Ltd.

Umweltbundesamt (2014) Submission under the United Nations Framework Convention on Climate Change and the Kyoto Protocol 2016 – National Inventory Report for the German Greenhouse Gas Inventory 1990-2014.

Yang, L. E., Hoffmann, P., Scheffran, J. , Rühe, S. , Fischereit, J. and Gasser, I. (2018), An Agent-Based Modeling Framework for Simulating Human Exposure to Environmental Stresses in Urban Areas, Urban Science, 2, 36.

How to cite: Hokamp, S., Rühe, S., and Scheffran, J.: Agent-based Modeling of Human Exposure to Urban Environmental Stressors – A Docking Study, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11820, https://doi.org/10.5194/egusphere-egu2020-11820, 2020

D2586 |
Héctor Angarita, Vishal Mehta, and Efraín Domínguez

Human population is progressing into a predominantly urban configuration. Currently, 3.5 billion people – 55% of the total human population – live in urban areas, with an increase to 6.68 billion (68%) projected by 2050. In this progressively more populated world, a central issue of sustainability assessments is understanding the role of cities as entities that, despite their comparatively small physical footprint (less than 0.5% of the global area) demand resources at regional and global scales.

Many of the resources that sustain urban population directly depend on the freshwater system: from direct fluxes from/to the immediate environment of cities for water supply or waste elimination, to water-dependent activities like biomass (food, biofuels, fibers) and energy production. Urban and freshwater system interactions are subject to multiple sources of non-linearity. Factors like the patterns of size or spatial distribution and interconnection of groups of cities; or the nested and hierarchical character of freshwater systems, can vastly influence the amount of resources required to sustain and grow urban population; likewise, equivalent resource demands can be met through different management strategies that vary substantially in their cumulative pressure exerted on the freshwater system.

Here we explore the non-linear character of those interactions, to i. identify water management options to avoid, minimize or offset regional impacts of growing urban populations, and ii. explore long term implications of such non-linearities in sustained resource base of urban areas. We propose a framework integrating three elements: 1. properties of the size and spatial distribution of urban center sizes, 2. scaling regime of urban energy resource dependencies, and 3. scaling regime of associated physical and ecological impacts in freshwater systems.

An example of this approach is presented in a case study in the Magdalena River Basin – MRB (Colombia). The basin covers nearly one quarter of Colombia’s national territory and provides sustenance to 36 million people, with three quarters of basin inhabitants living in medium to large urban settlements of populations of 12 000 or more inhabitants and 50% concentrated in the 15 largest cities. The case study results indicate that freshwater-mediated resource dependencies of urban population are described by a linear or super-linear regime that indicates a lack of scale economies, however, freshwater systems’ capacity to assimilate those resource demands is characterized by a sublinear regime. As a result, current practices and technological approaches to couple freshwater and urban systems will not be able to withstand the resource demands of mid-term future population scenarios.  Our approach allows to quantify the projected gaps to achieve a sustained resource base for urban systems in MRB.

How to cite: Angarita, H., Mehta, V., and Domínguez, E.: Non-linear interactions of urban and freshwater systems: Exploring implications for sustainability and water planning and management, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13031, https://doi.org/10.5194/egusphere-egu2020-13031, 2020

D2587 |
Chandrasekar V. Chandra, Haonan Chen, and Rob Cifelli

The operational Weather Surveillance Radar - 1988 Doppler (WSR-88D) network is an efficient tool for observing hydrometeorology processes and it forms the cornerstone of national weather forecast and warning systems. However, the observation performance of the WSR-88D network is severely hampered over the western U.S., due to 1) the radar network density is not as high as that over the eastern U.S.; 2) WSR-88D radar beams are often partially or fully blocked by the mountainous terrain in the western U.S. 

For example, the San Francisco Bay Area in Northern California, which supports one of the most prosperous economies in the U.S., is expected to be covered by two WSR-88D radars: KMUX and KDAX. The KMUX radar is located in the Santa Cruz Mountains at an elevation of over 1000 m above mean sea level (AMSL) compared with the densely populated valley regions which are near the sea level. Typically, the storms in Northern California have freezing levels approximately 1–2 km AMSL. As the distance from the radar increases, the KMUX radar beam can easily overshoot the mixed-phase hydrometeors in the bright band or snowflakes above the bright band, even if it is raining at the ground. The KDAX radar is located near the sea level in Davis, California. However, the KDAX radar beams are partially blocked by the Coast Ranges at low elevation angles. The coverage limitations of the KMUX and KDAX radars are further compounded by the complex precipitation microphysics as a result of land-ocean interaction in the coastal regions and orographic enhancement in the mountainous regions. As a result, it is still challenging to monitor and predict the changing atmospheric conditions using operational radars in the Bay Area, which will make the Bay Area particularly susceptible to catastrophic flooding that disrupts transportation, threatens public safety, and negatively impacts water quality. 

In this paper, we present an Advanced Quantitative Precipitation Information (AQPI) system built by NOAA and collaborating partners to improve monitoring and forecasting of precipitation and coastal flooding in the Bay Area. The high-frequency (i.e., C and X band) high-resolution gap-filling radars deployed as part of the AQPI program are detailed. A radar-based rainfall system is designed to improve real-time precipitation estimation over the Bay Area. The sensitivity of rainfall products on the occurrence of hydrologic extremes is investigated through a distributed hydrological model to improve the streamflow forecast. The performance of rainfall and associated hydrological impacts during the 2018-2019 and 2019-2020 winter storm seasons is quantified in the context of improving urban resiliency to natural disasters in such a complex environment. 

How to cite: Chandra, C. V., Chen, H., and Cifelli, R.: High-resolution polarimetric radar network for improving urban resilience to natural disasters in a complex environment, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18578, https://doi.org/10.5194/egusphere-egu2020-18578, 2020

D2588 |
Van-Thanh-Van Nguyen

There exists an urgent need to assess the possible impacts of climate change on the Intensity-Duration-Frequency (IDF) relations in general and on the design storm in particular for improving the design of urban water infrastructure in the context of a changing climate. At present, the derivation of IDF relations in the context of climate change at a location of interest has been recognized as one of the most challenging tasks in current engineering practices. The main challenge is how to establish the linkages between the climate projections given by Global Climate Models (GCMs) at the global scale and the observed extreme rainfalls at a given local site. If these linkages could be established, then the projected climate change conditions given by GCMs could be used to predict the resulting changes of local extreme rainfalls and related runoff characteristics.  Consequently, innovative downscaling approaches are needed in the modeling extreme rainfall (ER) processes over a wide range of temporal and spatial scales for climate change impact and adaptation studies in urban areas. Therefore, the overall objective of the present paper is to provide an overview of some recent progress in the modeling of extreme rainfall processes in a changing climate from both theoretical and practical viewpoints. In particular, the main focus of this paper is on recently developed statistical downscaling (SD) methods for linking GCM climate predictors to the observed daily and sub-daily rainfall extremes at a single site as well as at many sites concurrently. In addition, new SD procedures are presented for describing the linkages between GCM outputs and rainfall characteristics at a given location where the rainfall data are limited or unavailable, a common and crucial challenge in engineering practice.

How to cite: Nguyen, V.-T.-V.: On Statistical Modeling of Extreme Rainfall Processes for Urban Water Infrastructure Design in the Context of Climate Change, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19163, https://doi.org/10.5194/egusphere-egu2020-19163, 2020

D2589 |
| Highlight
Remko Uijlenhoet, Lotte de Vos, Aart Overeem, and Hidde Leijnse

Traditionally, hydrologists have relied on dedicated measurement equipment to do their business (e.g. rainfall-runoff modeling). Such instruments are typically owned and operated by government agencies and regional or local authorities. Installed and maintained according to (inter)national standards, they offer accurate and reliable information about the state of and fluxes in the hydrological systems we study as scientists or manage as operational agencies. Such standard instruments are often further developments of novel measurement techniques which have their origins in the research community and have been tested during dedicated field campaigns.

One drawback of the operational measurement networks available to the hydrological community today is that they often lack the required coverage and spatial and/or temporal resolution for high-resolution real-time monitoring or short-term forecasting of rapidly responding hydrological systems (e.g. urban areas). Another drawback is that dedicated networks are often costly to install and maintain, which makes it a challenge for nations in the developing world to operate them on a continuous basis, for instance.

Yet, our world is nowadays full of sensors, often related to the rapid development in wireless communication networks we are currently witnessing (notably 5G). Let us try to make use of such opportunistic sensors to do our (hydrologic) science and our (water management) operations. They may not be as accurate or reliable as the dedicated measurement equipment we are used to working with, let alone meet official international standards, but they typically come in large numbers and are accessible online. Hence, in combination with smart retrieval algorithms and statistical treatment, opportunistic sensors may provide a valuable complementary source of information regarding the state of our environment.

The presentation will focus on some recent examples of the potential of opportunistic sensing techniques in hydrology and water resources, from rainfall monitoring using microwave links from cellular communication networks (in Europe, South America, Africa and Asia), via crowdsourcing urban air temperatures using smartphone battery temperatures to high-resolution urban rainfall monitoring using personal weather stations.

How to cite: Uijlenhoet, R., de Vos, L., Overeem, A., and Leijnse, H.: Opportunistic sensing in hydrometeorology, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20583, https://doi.org/10.5194/egusphere-egu2020-20583, 2020

D2590 |
Anna Petit-Boix and Sina Leipold

Circular economy (CE) is gaining popularity at different levels with the promise of creating more sustainable processes. In this context, cities are implementing a number of initiatives that aim to turn them into sustainable circular systems. Whether these initiatives achieve their sustainability goals, however, is largely unknown. Nevertheless, as the application of CE strategies is actively encouraged by many policies across the globe, there is a need to quantify the environmental impacts and to identify the strategies that support urban sustainability. This paper analyses the extent to which research focuses on quantifying the environmental balance of CE initiatives promoted at the municipal level. To this end, the analysis scanned CE initiatives reported in cities around the globe and classified them into urban targets and CE strategies. In parallel, the paper conducted a review of the literature that uses industrial ecology tools to account for the environmental impacts of CE strategies. Results show a diverse geographical representation, as reported cities concentrated in Europe, whereas for environmental research, the main results came from China. In general, cities encourage strategies relating to urban infrastructure (47%), with and additional focus on social consumption aspects, such as repair and reuse actions. In comparison, research mainly addressed industrial and business practices (58%), but the approach to infrastructure was similar to that of cities, both with a special interest in waste management. Research has yet to assess social consumption and urban planning strategies, the latter essential for defining the impacts of other urban elements. Hence, there is a need to define the environmental impacts of the strategies that cities select in their quest for circularity. Research and practice can also benefit from working collaboratively so as to prioritize the CE strategies that best fit into the features of each urban area.

How to cite: Petit-Boix, A. and Leipold, S.: Circular economy in cities: Reviewing how environmental research aligns with local practices, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2464, https://doi.org/10.5194/egusphere-egu2020-2464, 2020

D2591 |
Fanni Vörös, Mátyás Magyari, and Béla Kovács

People have a basic need for moving – since the very beginning. What has changed is the hows and the whys of the route. With the advancement of technology we can travel more faster and more comfortable. Of course, not only the vehicles themselves, but also the devices inside them are becoming more modern and faster. One of the - maybe the most important - tools is the built-in navigation. It should have fast response time and it must provide appropriate amount of information to the driver.

We assumed that driving habits are influenced by lot of things, such as age, sex or residence. Drivers living in Hungary and Romania were examined in our project. Hungary is in Central Europe, in the Carpathian Basin. With about 10 million residents, it is a medium-sized member state of the European Union. Romania is at the junction of Central, Eastern, and South-eastern Europe and it is the 12th largest country and also the 7th most populous member state of the EU with almost 20 million inhabitants. The area difference between the two countries is already one aspect, which is supposed to be associated with different driving habits. Differences in road quality, GDP or infrastructure can also have an effect on it.

To test the assumptions we created two Google Forms - one for the Hungarian drivers (in Hungarian) and one for those who live in Romania. The latter was available in both Romanian and Hungarian, because the largest minority group in Romania are the Hungarians – in terms of the questionnaire the border of the countries were relevant. Both questionnaires had the same structure (three parts) and questions: the first parts contain 17 general, mandatory questions like age, education level, questions about the driver’s car (brand, age). Navigation habits are closely linked to driving habits and we put more emphasis on it. Depending on whether someone is using built-in car navigation or not, we have asked different questions – 3 if the filler does not have one, and 30 if he/she has in-built car navigation GPS. Most of our questions were about these tools but we gathered some information about mobile application usage too.

There are similarities and also differences in the results. Hungarian drivers have few years older cars (in average) than the Romanian cars (which is equivalent to the EU average), but most of them drive “second hand” cars (in both countries). Consequently, most people could not choose whether they would like a built-in GPS or not. Few respondents said that they would not use the device under any circumstances. So it can be said that people basically do not consider GPS unnecessary or discarded. The number of people who own and use in-built car GPS is roughly the same in the two countries.





FV is supported by the ÚNKP-19-3 New National Excellence Program of the Ministry for Innovation and Technology.

How to cite: Vörös, F., Magyari, M., and Kovács, B.: Comparison of driving habits of drivers living in Hungary and Romania, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-150, https://doi.org/10.5194/egusphere-egu2020-150, 2019

D2592 |
Vasile Efros, Luminita-Mirela Lazarescu, and Vasilica-Danut Horodnic

         Housing, associated in the specialty literature with the habitat, is a dynamic process, circumscribed to human existence that is significantly influenced by the technological progress of the last decades. The access to information, the alert pace of life in the urban environment, the multiplication of population concerns, the need for privacy have created new preferences for housing and new expectations and needs of the residents in relation to the utilities, facilities and services available whitin the urban settlements. In consenquence, constant changes regarding housing-needs justifies the measures to assess the living conditions within a settlement.

       The present article proposes an empirical analysis on the perception of the population on the conditions under which the housing is carried out in the city of Radauti, a city with a population of 34,692 inhabitants, which after the fall of the communist regime undergoes a process of urban regeneration, like many other small medium-sized cities in the ex-socialists states of Eastern Europe. The research used the method of sociological inquiry by applying a questionnaire to a sample of 350 inhabitants with a permanent residence in the municipality of Radauti who were selected from the lists of citizens with voting rights from the 15 existing constituencies, following the representation of the three age categories. The research related to criteria associated with the characteristics of the housing environment and to the criteria regarding the accessibility of some utilities and services, for each category being selected variables that can be improved by involving the local administration (characteristics of buildings and housing, existence and access to utilities, the arrangement of the parking lots, of the communication paths, of the spaces for pedestrian movement, the urban image etc.). 

        The interpretation of results allowed the association of the satisfaction and dissatisfaction of the respondents with concrete aspects of the settlement, which made it possible to individualize the generating factors of some situations that were negatively appreciated by the population. This fact confirmed the hypothesis that there is an important gap between the needs of the population and the concrete situation of the facilities, utilities and services to which the population has access, emphasizing the unattractive aspects of the living environment and the anticipated responses of the users to the future conditions. Research has also indicated that the evaluation of the population’s satisfaction regarding the main aspects which define housing in Radauti is a useful feed-back for policies makers indicating the concrete situations in which it could intervene to increase the quality of housing within the settlement.


Key words: housing quality,  population needs, assessment, satisfaction, housing environment

How to cite: Efros, V., Lazarescu, L.-M., and Horodnic, V.-D.: Assessing resident's satisfaction regarding housing environment - Case study Radauti municipality, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-392, https://doi.org/10.5194/egusphere-egu2020-392, 2019

D2593 |
Hsin Yang and Hsueh-Sheng Chang

In the past, Taiwan's spatial planning has focused on the development of urban areas and overlooked rural areas, which has led to difficulty in promoting rural-urban relationships. This study suggests that rural areas should not just be seen as single entities, but as a collection of distinct areas. Since it is becoming important to develop a new spatial planning in Taiwan, this study examines territorial space structure from a regional perspective, with a focus on the development of the rural areas of Yunlin & Chiayi. Consequently, this study aims to classify rural areas by the procedure of typology, in terms of their development dynamics, location, and economic structure, selecting appropriate indicators for each focus of inquiry. The study then uses cluster analysis, accessibility analysis and overlay analysis methods to classify information about these rural areas. This approach will show the differences in their spatial characteristics along with their histories of development through time, as well as the relationship between these rural areas and the overall region in which they are situated. It is hoped that this research will provide a more accurate description than currently exists of the rural areas studied in this paper, and that this information will be a useful resource to those who are developing new plans and policies, so that better integration can occur between urban and rural in Taiwan.

How to cite: Yang, H. and Chang, H.-S.: Classification of Rural Areas by Typology : A Case Study of Yunlin & Chiayi, Taiwan, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6662, https://doi.org/10.5194/egusphere-egu2020-6662, 2020

D2594 |
| Highlight
Wei-Jhe Chen and Jehn-Yih Juang

As urban heat island effect intensifies, weather data produced by a mainly official weather station are not adaptable to represent and reflect the microclimate situation in a city. This study selected 17 weather stations in Tainan, Taiwan, to estimate the wind velocity at pedestrian-level and utilized 102 automatic stations from high-density street-level air temperature observation network (HiSAN) to measure air temperature at a height of 2 meters. Based on those observed weather data and urban environmental information provided by the government. This study established a method of generating high-resolution pedestrian-level weather information for urban areas. The method has taken urban morphological parameters, such as surface roughness, into consideration to be the factor of evaluating wind velocity. By interpolation and extrapolation, each grid obtained microclimate weather data on the pedestrian-level scale. In addition, both pieces of information were integrated into consideration of the thermal comfort index and presented by a useful tool, WebGIS. The application could provide a simple way to visualize an instantly environmental situation for urban planning and decision making.

How to cite: Chen, W.-J. and Juang, J.-Y.: Investigating Pedestrian-level Wind Fields and Thermal Environments Under Different Urban Morphology, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13352, https://doi.org/10.5194/egusphere-egu2020-13352, 2020

D2595 |
Julien Cravero, Pierre-Antoine Versini, Adélaïde Feraille, Jean-François Caron, and Ioulia Tchiguirinskaia

Nature-based solutions appear to be an interesting option for enhancing the thermal comfort of the urban population during summer, while providing multiple services (e.g. biodiversity enhancement, the reduction in buildings energy consumption, stormwater management, acoustic insulation or air purification). However, the effects of green infrastructures on thermal comfort are not properly characterized, which prevents urban planning policies to be consistent.

The impacts of a single idealized tree on its microclimate are studied. The sensible heat flux emitted by the soil to the air is computed by solving the heat equation in a semi-infinite domain with a Robin boundary condition representing the energy balance of the soil. The sensible heat flux emitted by the vegetation is computed in two ways: with Newton’s law and with an energy-balance approach. This model is applicated to a tree-shaped structure supporting climbing plants and compared with the experimental data collected. The prototype has been built to assess the cooling performance of this type of vegetation, and particularly the part played by soil shading, evapotranspiration (i.e. the latent heat flux emitted to the air by the plants and the soil) and absorbed solar radiation. These results may permit to estimate the contribution of vegetation for mitigating urban heat island effects on a larger scale.

How to cite: Cravero, J., Versini, P.-A., Feraille, A., Caron, J.-F., and Tchiguirinskaia, I.: The effects of trees on outdoor thermal comfort in cities, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19602, https://doi.org/10.5194/egusphere-egu2020-19602, 2020

D2596 |
Marharyta Kazyrenka and Tamara Kukharchyk

In the paper the results of study of surface runoff deposits and soils in two Belarusian cities are shown. It is known that urban soils are under significant anthropogenic impact. Investigations of industrial areas are limited due to the lack of direct access to them. In the same time soils on industrial sites can be a significant source of further contamination of adjacent urban area as a result of water and wind activity. Thus, surface runoff deposits can serve as an indicator of industrial soil pollution. Moreover, the redistribution of pollutants with surface runoff can also cause secondary urban soil contamination. The understanding of pollutants migration and accumulation in urban soils and their possible exposure routes into rivers is an important part of urban area investigations and planning.

The main objective of the study was an assessment the levels of pollutants in runoff deposits and revealing the role of surface runoff in the migration of pollutants from industrial sites.

Investigations of urban areas were carried out in 2008–2019 in Minsk and Lida, Grodno region (Belarus). Soil samples were taken form upper soil layer (mainly 0-5, 0-10 cm) in the territory of industrial enterprises and in their impact zones. Runoff deposits were sampled mainly in areas covered with asphalt or concrete near industrial enterprises and along roads. Particular attention was paid to areas with a slope of surface from enterprises. AAS  method for heavy metals  determination was applied; the content of total petroleum hydrocarbons was determined by fluorimetric method. 

Elevated content of heavy metals and petroleum hydrocarbons in surface runoff deposits has been revealed. The concentrations of pollutants in runoff deposits were many times higher than in soils. Significance of differences between pollutants content in soils and deposits samples is statistically confirmed. Exceeding the maximum permissible concentrations for petroleum hydrocarbons was observed in 100%, for metals – in 70–100% of analyzed surface runoff deposits samples.

The findings confirm an important role of surface runoff in migration and accumulation of pollutants and suggest the need for more in-depth studies of urban areas with the study of local erosive processes, the characteristics of formation  and role of surface runoff in the migration and redistribution of pollutants outside their direct sources. The adoption of measures to prevent pollutants migration from industrial areas is an important factor in improving the state of soils in urban areas.

How to cite: Kazyrenka, M. and Kukharchyk, T.: Surface runoff deposits and soils contamination in urban areas in Belarus, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21405, https://doi.org/10.5194/egusphere-egu2020-21405, 2020

D2597 |
Yangzi Qiu, Ioulia Tchiguirinskaia, and Daniel Scherzter

Nature-Based Solutions (NBS) practices provide many benefits for sustainable development of urban environments, one of which is their ability to mitigate the urban waterlogging. In many previous studies, the performances of NBS practices are analysed with the semi-distributed model and artificial rainfall without considering the spatial variability of rainfall. However, the NBS practices are decentralized in urban areas, their hydrological response is very depends on the small-scale heterogeneity of urban environments. Therefore, this research aims to investigate the impacts of small-scale rainfall variability on the hydrological responses of NBS practices.

In this study, the hydrological response of NBS practices was analysed at the urban catchment scale. A 5.2 km2 semi-urban catchment (Guyancourt, located in the South-West of Paris) are investigated under various future NBS implementation scenarios (porous pavement, green roof, rain garden and combined). Regarding the objective of this research, three typical rainfall events are selected. Three sets of distributed rainfall data at a high resolution of 250 m×250 m×3.41 min were obtained from the X-band radar of Ecole des Ponts ParisTech (ENPC). In addition, three sets of corresponded homogeneous rainfall data are applied and used for comparing with the distributed one. Furthermore, a fully distributed and grid based hydrological model (Multi-Hydro), developed at ENPC, which takes into consideration the spatial variability of the whole catchment at 10 m scale. The hydrological response of NBS scenarios was analysed with the percentage error on total volume and peak discharge, with regards to the baseline scenario (current configuration).

Results show that the spatial variability of rainfall has the impact on the hydrological response of NBS scenarios in varying degrees, and it is more evident for green roof scenario. In three rainfall events, the maximum percentage error on peak discharge of green roof scenario under distributed rainfall is 23 %, while that of the green roof scenario under homogeneous rainfall is 17.7%. Overall, the results suggest that the implementation of porous pavement and rain garden is more flexible than implementation of green roof in a semi-urban catchment.

How to cite: Qiu, Y., Tchiguirinskaia, I., and Scherzter, D.: Is the hydrological response of Nature-Based Solutions related to the spatial variability of rainfall?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1100, https://doi.org/10.5194/egusphere-egu2020-1100, 2019

D2598 |
Gianluca Pagnoni, Alberto Armigliato, Stefano Tinti, and Filippo Zaniboni

Siracusa is an important historical city of Greek origin, located on the southern part of the eastern coast of Sicily. The old town developed on the island of Ortigia, and expanded on the near mainland, but later it declined and during the Middle Ages it occupied only the island. The development of the built areas on the mainland restarted at the end of the nineteenth century, with the construction of a number of new quarters. Nowadays the island of Ortigia is connected to the rest of the town by two drive-over bridges. The history of Siracusa as well as of the eastern coast of Sicily is marked by destructive earthquake events that caused significant damage and many fatalities, and also by lethal tsunamis (occurred in the years 1169, 1693 and 1908). Indeed, this region is one of the coastal areas most prone to tsunami attacks in the Mediterranean Sea, being affected by local-source tsunamis and also by those generated by earthquakes in the Western Hellenic Arc.

For these reasons, in the last decade the need has developed to prepare adequate evacuation measures to respond to tsunami hazardous events. This work, using the method proposed by Pagnoni et al. (2020) and applied to the near town of Augusta, studies the tsunami risk for different inundation levels. The results are provided in terms of the Human Damage (HD), which is the number of people involved and the number of fatalities, and of the Economic Loss (EL), which returns the loss of economic value of buildings affected by tsunamis. Maps of HD and EL per each inundation scenario allow one to understand which areas of Siracusa are most involved and also to identify evacuation paths to potential safe collection areas and/or buildings for efficient emergency plans.

How to cite: Pagnoni, G., Armigliato, A., Tinti, S., and Zaniboni, F.: Risk assessment for tsunami events in the city of Siracusa, Italy, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13115, https://doi.org/10.5194/egusphere-egu2020-13115, 2020

D2599 |
| Highlight
Guillaume Drouen, Daniel Schertzer, and Ioulia Tchiguirinskaia

As cities are put under greater pressure from the threat of the global impact of climate change, in particular the risk of heavier rainfall and flooding, there is a growing need to establish a hierarchical form of resilience in which critical infrastructure can become sustainable. The main difficulty is that geophysics and urban dynamics are strongly nonlinear with an associated, extreme variability over a wide range of space-time scales. To better link the fundamental and experimental research on these topics, an advanced urban hydro-meteorological observatory with the associated SaaS developments, the Fresnel platform (https://hmco.enpc.fr/portfolio-archive/fresnel-platform/), has been purposely set-up to provide the concerned communities with the necessary observation data thanks to an unprecedented deployment of higher resolution sensors, that easily yield Big Data.

To give an example, the installation of the polarimetric X-band radar at the ENPC’s campus (East of Paris) introduced a paradigm change in the prospects of environmental monitoring in Ile-de France. The radar is operated since May 2015 and has several characteristics that makes it of central importance for the environmental monitoring of the region. In particular, it demonstrated the crucial importance to have high resolution 3D+1 data, whereas earlier remote sensing developments have been mostly focused on vertical measurements.

This presentation discusses the associated Fresnel SaaS (Sofware as a Service) platform as an example of nowadays IT tools to dynamically enhance urban resilience. It is rooted on an integrated suite of modular components based on an asynchronous event-driven JavaScript runtime environment. It features non-blocking interaction model and high scalability to ensure optimized availability. It includes a comprehensive and (real-time) accessible database to support multi-criteria choices and it has been built up through stakeholder consultation and participative co-creation. At the same time these components are designed in such a way that they are tunable for specific case studies with the help of an adjustable visual interface. Depending on that case study, these components can be integrated to satisfy the particular needs with the help of maps other visual tools and forecasting systems, eventually from third parties.

All these developments have greatly benefited from the support of the Chair “Hydrology for a Resilient City” (https://hmco.enpc.fr/portfolio-archive/chair-hydrology-for-resilient-cities/) endowed by the world leader industrial in water management and from previous EU framework programmes. To sustain the necessary public-private partnerships, Fresnel facilitates synergies between research and innovation, fosters the theoretical research, national and international collaborative networking, and the development of various aspects of data science for a resilient city.

How to cite: Drouen, G., Schertzer, D., and Tchiguirinskaia, I.: New Technologies, Techniques and Tools to Dynamically Manage Urban Resilience: the Fresnel Platform for Greater Paris, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20197, https://doi.org/10.5194/egusphere-egu2020-20197, 2020

D2600 |
Olga Krukowskaya and Hanna Malchykhina

Reducing the risks associated with the effects of polluted air on public health is one of the main tasks of sustainable urban development. This problem can be solved in two different ways: by emission reduction and by minimization of human exposure to elevated concentrations of pollutants. In the context of the second approach, it is important to plan the urban area in order to minimize places with a large number of people and poor dispersion conditions.

For this purpose investigation and identification of street canyons in Minsk city was performed. With population ca 2 mln inhabitants Minsk is one of the most populated European cities. Due to many historical destructions of the city nowadays it has mainly planned structure of streets and buildings according to General plans of urban development designed in the second part of the XX century. According to the plans Minsk has relatively wide main transport lines surrounded by mid-level buildings and has good conditions for air circulation and air pollutions spatial dispersion. Nevertheless, there is some location in the city with conditions close to urban street canyons and is characterised with high pedestrian and traffic intensity. Besides in modern construction so density planning not so rare. That's in addition to limited air pollution concentration researches makes important measurements and assessments in such conditions in Minsk.

For sampling, urban canyons NOx concentration in the air were carried out in 2012-2019 in Minsk. Air was sampled on both sides of “street canyons” taking into account weather conditions. During sampling, traffic accounting was carried out. The concentration of NOx was determined by the fluorimetric method.

Obtained results have shown that the actual formation of “street canyons” occurs even with a low height of buildings along to the streets with heavy traffic. It has been shown that a statistically significant increase of NOx content by 20–50% on the windward side compared to the leeward with buildings height comparable to the width of streets. Besides statistical reliable correlation between emissions levels (assessed based on traffic data) and measured concentrations are observed.

Identified patterns of air concentration in combination with GIS allow identifying areas with potential increased risk of exposure. This knowledge will help to plan urban territory in a sustainable way.

How to cite: Krukowskaya, O. and Malchykhina, H.: Air pollution studies in “street canyons” in Minsk and urban planning for minimization of its exposure, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21547, https://doi.org/10.5194/egusphere-egu2020-21547, 2020

D2601 |
Hanna Malchykhina and Olga Krukowskaya

Air pollution problem is the main challenge of the present. It is known that the transport is one of the main emission sources of such pollutants as NOx, CO, and TSP. Thus decreasing of emissions from the mobile sources could be one of the key elements of air emissions problem solution. The developing of measures to reduce the negative impact of the air pollution requires detailed information on emissions sources and the relationship between emissions and air quality. The article is devoted to assessment of annual variability of air pollution by transport and revealing the correlation between emissions of pollutants and their concentration.

Emissions assessment of main pollutants (NOx, CO, SO2, NMVOC, TSP) was carried out using emissions model COPERT, which is widely used to assess emissions from transport sector on different levels of aggregation – from city to country. The main input parameters of the model are vehicle fleet information (number of vehicles by fuel type, environmental standards, and the engine capacity), fuel consumption, meteorological conditions, mileage by vehicle types, average speeds for each category of vehicles. Data on pollutants concentration in the air were obtained from the National environmental monitoring system of Belarus.

It was shown that the annual emissions variability differs depending on type of pollutants. In particular the maximum carbon monoxide emissions were observed in cold months, and minimum - in warm months. The main source of CO emissions variation is emissions during the cold start. In the case of NMVOC emissions the situation is reverse.  Maximum emissions were obtained in August and minimum emissions in winter months. Comparison of the obtained emissions data with the concentration has shown high correlation for CO and NMVOC.

The findings could help to understand ways of air quality formation thereby to develop a solution on air quality management.

How to cite: Malchykhina, H. and Krukowskaya, O.: Assessment of seasonal variability of air pollution by transport in Belarus, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21404, https://doi.org/10.5194/egusphere-egu2020-21404, 2020

D2602 |
Ioulia Tchiguirinskaia, Pierre-Antoine Versini, and Daniel Schertzer

A wider recognition of climate change enhances in the society the 3R approach – Reduce, Recycle and Reuse –, thus broadening the spectrum of Urban Geoscience topics. This strengthens also the consensus that business models of companies are often too focused on their financial value, to the detriment of social and environmental added value. It therefore seems timely to change this way of doing things so that their growth is built more as part of a sustainable development approach, by emphasising the paradigm shift of ‘shared value’.

'Shared value' means that by meeting the needs and challenges of society, businesses can create their economic value in a way that also benefits society, in direct link with COP21's commitments and in response to energy, environmental and IT transition laws, hence bringing political ambition and market reality together. To highlight such opportunities, this presentation will capitalise on several research initiatives launched in Greater Paris during recent years related to this topic (https://hmco.enpc.fr/portfolio-archive/):

(i) research to extend non-linear approaches in environment and geophysics;

(ii) results on defining environmental indicators for our cities - considering their multimodal, multiscale and multifunctional structure - to quantify their environmental impacts (e.g., thermal, visual comfort, air quality, heat island mitigation, stormwater management etc.);

(iii) numerous instrumentation and modelling experiments related to the impacts of climate change and to the means of their attenuation;

(iv) results on the monetisation of amenities provided by Blue-Green Solutions in urban areas and their large-scale socio-economic contextualisation;

(v) environmental assessment of many (infra)structures that take into account their design method, implementation, operation, maintenance and end-of-life.

All these research initiatives constitute the basis for the ‘shared value’ theoretical emergence in the 4C framework – Cognitive, Collaborative, Coevolutionary and Complex – systems, with a practical methodology towards the sustainable, desirable and resilient city and call for larger developments of Urban Geosciences.  

How to cite: Tchiguirinskaia, I., Versini, P.-A., and Schertzer, D.: From 3R Approach to 4C Systems: on the Road to Sustainable, Desirable and Resilient City, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21423, https://doi.org/10.5194/egusphere-egu2020-21423, 2020

D2603 |
Guillem Subiela, Miquel Vilà, Roser Pi, and Elena Sánchez

Studying urban geology is a key way to identify municipal issues involved with urban development and sustainability, land resources and hazard awareness in highly populated areas. In the last decade, one of the lines of work of the Catalan Geological Survey (Institut Cartogràfic i Geològic de Catalunya) has been the development of (i) 1:5.000 scale Urban Geological Map of Catalonia project. Besides, two pilot projects have recently been started: (ii) the system of layers of geological information and (iii) the fundamental geological guides of municipalities. This communication focuses on the presentation of these projects and their utility, with the aim of finding effective ways of transferring geological knowledge and information of a territory, from a geological survey perspective.

The 1:5.000 urban geological maps of Catalonia (i) have been a great ambitious project focused on providing detailed, consistent and accurate geological, geotechnical and anthropogenic activity information of the main urban areas of Catalonia. Nevertheless, it must be taken into account that the compilation and elaboration of a large volume of geological information and also the high level of detail require a lot of time for data completeness.

In order to optimize a greater distribution of information, a system of layers of geological information (ii) covering urban areas is being developed. This pilot project consists of providing specific layers of Bedrock materials, Quaternary deposits, anthropogenic grounds, structural measures, geochemical compositions, borehole data and so on. However, as information layers are treated individually, it may not be clear the coherence between data from different layers of information and its use is currently limited to Earth-science professionals working with geological data.

Hence, as a strategy to reach a wider range of users and also provide a homogeneous and varied geological information, the development of fundamental geological guides for municipalities is also being carried out (iii). These documents include the general geological characterization of the municipality, the description of the main geological factors (related to geotechnical properties, hydrogeology, environmental concerns and geological hazards and resources) and the list of the sources of geological information to be considered. Moreover, each guide contains a 1:50.000 geological map that has cartographic continuity with the neighbouring municipalities. The municipal guides allow a synthesis of the geological environment of the different Catalan municipalities and give fundamental recommendations for the characterization of the geological environment of the municipality.

In conclusion, the three projects facilitate the characterization of geological environment of urban areas, the evaluation of geological factors in ground studies and also, in general, the management of the environment. These products differ depending on the degree of detail, the coherence of the geological information, the necessary knowledge for their execution or their purpose of use. This set of projects defines a geological urban framework, which is adjusted depending on the government’s requirements, the society’s needs and the geological survey’s available resources.

How to cite: Subiela, G., Vilà, M., Pi, R., and Sánchez, E.: Three different approaches to provide urban geological information from a geological survey perspective: the Catalan case study, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13620, https://doi.org/10.5194/egusphere-egu2020-13620, 2020

D2604 |
Yuyu Zhou, Xuecao Li, Ghassem Asrar, Zhengyuan Zhu, and Lin Meng

Changes in urban environments play important roles in sustainable urban development. Satellite observations in fine spatial and temporal resolutions, together with new computer technologies, provide the possibility to monitor these changes across large geographic areas and over a long time period. In this study, we developed new algorithms to characterize dynamics of urban extent, urban heat island, and phenology (i.e., onsets of green-up and senescence phases) and successfully implemented them on the advanced Google Earth Engine, a start-of-art platform for planetary-scale data analysis, mapping, and modelling. The evaluation indicates that the proposed algorithms are robust and perform well in deriving changes in urban environments. Finally, we explored the implications of urban environment changes in the coupled human-nature system by investigating the responses of building energy use and pollen season to these changes. The resulted products of annual dynamics of urban extents, urban heat island, and phenology indicators from this study offer new datasets for relevant urban studies such as modeling urban sprawl over large areas and investigating ecosystem responses and human activities to urbanization.

How to cite: Zhou, Y., Li, X., Asrar, G., Zhu, Z., and Meng, L.: Satellite-based monitoring urban environmental change and its implications in the coupled human-nature system, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10556, https://doi.org/10.5194/egusphere-egu2020-10556, 2020

D2605 |
Clément Brochet, Auguste Gires, Daniel Schertzer, and Ioulia Tchiguirinskaia

Extreme rainfalls have strong consequences in urban area. Their knowledge is required to properly handle storm water management systems and avoid urban flooding as well as optimize depollution capabilities. Hence improving understanding of future rainfall extreme in a changing climate is of paramount interest to adapt the cities and increase their resilience.      

In this paper future rainfall extremes are quantified through the universal multifractal (UM) framework. This is a parsimonious framework that has been widely used to characterize and simulate geophysical, extremely variable fields, such as rainfall, across wide range of scales. It has also been used for statistical downscaling of geophysical fields.

Here, we apply this formalism to analyse output data from Regional Climate Models CNRM-CM5 and SMHI-RCA4 over the European-Mediterranean domain EUR-11 of the CORDEX Project. We first use the multifractal analysis techniques to characterize the scaling behaviour of future rainfall .  The three UM parameters are then assessed. The notion of maximum observable singularity is then used to quantify extremes across the available scales  (12.5 km and 1 hour resolution at maximum)

Finally, initial work using discrete cascades, to generate realistic rainfall series at higher resolution with very light parametrization will be presented. Basically the underlying cascade process retrieved on the available scales is continued down to the scales required for urban hydrology applications. Both spatial and temporal downscaling are carried out, allowing to get new insights on how to model seasonal effects using multifractal formalism.

How to cite: Brochet, C., Gires, A., Schertzer, D., and Tchiguirinskaia, I.: Discrete cascade disaggregation of climate models for high resolution rainfall estimation in urban environment, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11186, https://doi.org/10.5194/egusphere-egu2020-11186, 2020