Large-scale flooding analysis in the suburbs of Tokyo Metropolis caused by levee breach of the Tone River using a 2D hydrodynamic model

In order to assess the effects of climate change on flood disasters in urban areas, we applied a two dimensional finite element hydrodynamic model (2D-FEM) to simulate flood processes for the case analysis of levee breach caused by Kathleen Typhoon on 16 September 1947 in Kurihashi reach of Tone River, upstream of Tokyo area. The purpose is to use the model to simulate flood inundation processes under the present topography and land-use conditions with impending extreme flood scenarios due to climate change for mega-urban areas like Tokyo. Simulation used 100 m resolution topographic data (in PWRI), which was derived from original LiDAR (Light Detection and Ranging) data, and levee breach hydrographic data in 1947. In this paper, we will describe the application of the model with calibration approach and techniques when applying for such fine spatial resolution in urban environments. The fine unstructured triangular FEM mesh of the model appeared to be the most capable of introducing of constructions like roads/levees in simulations. Model results can be used to generate flood mapping, subsequently uploaded to Google Earth interface, making the modeling and presentation process much comprehensible to the general public.

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Combined fluvial and pluvial urban flood hazard analysis: method development and application to Can Tho City, Mekong Delta, Vietnam

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-3-4967-2015 ◽

2015 ◽

Vol 3 (8) ◽

pp. 4967-5013 ◽

Cited By ~ 1

Author(s):

H. Apel ◽

O. M. Trepat ◽

N. N. Hung ◽

D. T. Chinh ◽

B. Merz ◽

...

Keyword(s):

Hydrodynamic Model ◽

Urban Areas ◽

Large Scale ◽

Method Development ◽

Flood Hazard ◽

Hazard Analysis ◽

Mekong Delta ◽

Rain Gauge ◽

Convective Precipitation ◽

Can Tho City

Abstract. Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas, and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either fluvial or pluvial flood hazard, studies of combined fluvial and pluvial flood hazard are hardly available. Thus this study aims at the analysis of fluvial and pluvial flood hazard individually, but also at developing a method for the analysis of combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as example. In this tropical environment the annual monsoon triggered floods of the Mekong River can coincide with heavy local convective precipitation events causing both fluvial and pluvial flooding at the same time. Fluvial flood hazard was estimated with a copula based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. Pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data, and a stochastic rain storm generator. Inundation was simulated by a 2-dimensional hydrodynamic model implemented on a Graphical Processor Unit (GPU) for time-efficient flood propagation modelling. All hazards – fluvial, pluvial and combined – were accompanied by an uncertainty estimation considering the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by percentile maps. The results are critically discussed and ways for their usage in flood risk management are outlined.

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The Use of Social Media for Urban Planning

Geospatial Intelligence ◽

10.4018/978-1-5225-8054-6.ch044 ◽

2019 ◽

pp. 1049-1070

Author(s):

Fabian Neuhaus

Keyword(s):

Social Media ◽

Big Data ◽

Urban Areas ◽

Large Scale ◽

Urban Environments ◽

Data Systems ◽

User Management ◽

Social Nature ◽

User Data ◽

Use Of Social Media

User data created in the digital context has increasingly been of interest to analysis and spatial analysis in particular. Large scale computer user management systems such as digital ticketing and social networking are creating vast amount of data. Such data systems can contain information generated by potentially millions of individuals. This kind of data has been termed big data. The analysis of big data can in its spatial but also in a temporal and social nature be of much interest for analysis in the context of cities and urban areas. This chapter discusses this potential along with a selection of sample work and an in-depth case study. Hereby the focus is mainly on the use and employment of insight gained from social media data, especially the Twitter platform, in regards to cities and urban environments. The first part of the chapter discusses a range of examples that make use of big data and the mapping of digital social network data. The second part discusses the way the data is collected and processed. An important section is dedicated to the aspects of ethical considerations. A summary and an outlook are discussed at the end.

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Rapid Global Exposure Assessment for Extreme River Flood Risk Under Climate Change

Journal of Disaster Research ◽

10.20965/jdr.2016.p1128 ◽

2016 ◽

Vol 11 (6) ◽

pp. 1128-1136 ◽

Cited By ~ 3

Author(s):

Youngjoo Kwak ◽

◽

Yoichi Iwami ◽

Keyword(s):

Climate Change ◽

Risk Assessment ◽

Flood Risk ◽

Large Scale ◽

Flood Hazard ◽

Data Availability ◽

Flood Risk Assessment ◽

Daily Data ◽

Extreme Flood ◽

River Flood

Globally, large-scale floods are one of the most serious disasters, considering increased frequency and intensity of heavy rainfall. This is not only a domestic problem but also an international water issue related to transboundary rivers in terms of global river flood risk assessment. The purpose of this study is to propose a rapid flood hazard model as a methodological possibility to be used on a global scale, which uses flood inundation depth and works reasonably despite low data availability. The method is designed to effectively simplify complexities involving hydrological and topographical variables in a flood risk-prone area when applied in an integrated global flood risk assessment framework. The model was used to evaluate flood hazard and exposure through pixel-based comparison in the case of extreme flood events caused by an annual maximum daily river discharge of 1/50 probability of occurrence under the condition of climate change between two periods, Present (daily data from 1980 to 2004) and Future (daily data from 2075 to 2099). As preliminary results, the maximum potential extent of inundation area and the maximum number of affected people show an upward trend in Present and Future.

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Climate Change and Conservation Biology as it Relates to Urban Environments

Recerca Revista de pensament i anàlisi ◽

10.6035/recerca.2020.25.2.4 ◽

2020 ◽

Author(s):

Samantha Noll ◽

Michael Goldsby

Keyword(s):

Climate Change ◽

Conservation Biology ◽

Urban Areas ◽

Global Climate ◽

Local Level ◽

Urban Environments ◽

Dynamic Changes ◽

Weather Patterns ◽

Weather Events ◽

Urban Contexts

Climate change continues to have recognizable impacts across the globe, as weather patterns shift and impacts accumulate and intensify. In this wider context, urban areas face significant challenges as they attempt to mitigate dynamic changes at the local level — changes such as those caused by intensifying weather events, the disruption of critical supplies, and the deterioration of local ecosystems. One field that could help urban areas address these challenges is conservation biology. However, this paper presents the argument that work in urban contexts may be especially difficult for conservation biologists. In light of current climate change predictions, conservation biology may need to abandon some of its core values in favor of commitments guiding urban ecology. More broadly, this essay aims to reconcile the goals of restoration and conservation, by reconceptualizing what an ecosystem is, in the context of a world threatened by global climate change.

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A 30-meter resolution national urban land-cover dataset of China, 2000–2015

10.5194/essd-2019-65 ◽

2019 ◽

Cited By ~ 2

Author(s):

Wenhui Kuang ◽

Shu Zhang ◽

Xiaoyong Li ◽

Dengsheng Lu

Keyword(s):

Land Use ◽

Land Cover ◽

Urban Areas ◽

Vegetation Index ◽

Urban Land ◽

Google Earth ◽

Urban Environments ◽

Urban Land Use ◽

Environmental Research ◽

Urban Land Cover

Abstract. Accurate urban land-cover datasets are essential for mapping urban environments. However, a series of national urban land-cover data covering more than 15 years that characterizes urban environments is relatively rare. Here we propose a hierarchical principle on remotely sensed urban land-use/cover classification for mapping intra-urban structure/component dynamics. China's Land Use/cover Dataset (CLUD) is updated, delineating the imperviousness, green surface, waterbody and bare land conditions in cities. A new data subset called CLUD-Urban is created from 2000 to 2015 at five-year intervals with a medium spatial resolution (30 m). The first step is a prerequisite to extract the vector boundaries covered with urban areas from CLUD. A new method is then proposed using logistic regression between urban impervious surface area (ISA) and the annual maximum Normalized Difference Vegetation Index (NDVI) value retrieved from Landsat images based on a big-data platform with Google Earth Engine. National ISA and urban green space (UGS) fraction datasets for China are generated at 30-meter resolution with five-year intervals from 2000 to 2015. The overall classification accuracy of national urban areas is 92 %. The root mean square error values of ISA and UGS fractions are 0.10 and 0.14, respectively. The datasets indicate that the total urban area of China was 6.28 × 104 km2 in 2015, with average fractions of 70.70 % and 26.54 % for ISA and UGS, respectively. The ISA and UGS increased between 2000 and 2015 with unprecedented annual rates of 1,311.13 km2/yr and 405.30 km2/yr, respectively. CLUD-Urban can be used to enhance our understanding of urbanization impacts on ecological and regional climatic conditions and urban dwellers' environments. CLUD-Urban can be applied in future researches on urban environmental research and practices in the future. The datasets can be downloaded from https://doi.org/10.5281/zenodo.2644932.

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Mid-21st century air quality at the urban scale under the influence of changed climate and emissions: case studies for Paris and Stockholm

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-27041-2015 ◽

2015 ◽

Vol 15 (19) ◽

pp. 27041-27085

Author(s):

K. Markakis ◽

M. Valari ◽

M. Engardt ◽

G. Lacressonnière ◽

R. Vautard ◽

...

Keyword(s):

Climate Change ◽

Urban Areas ◽

Large Scale ◽

Regional Scale ◽

Influential Factor ◽

Daily Average ◽

Pollutant Concentrations ◽

Emission Projections ◽

The Impact ◽

The City

Abstract. Ozone, PM10 and PM2.5 concentrations over Paris, France and Stockholm, Sweden were modeled at 4 and 1 \\unit{km} horizontal resolutions respectively for the present and 2050 periods employing decade-long simulations. We account for large-scale global climate change (RCP-4.5) and fine resolution bottom-up emission projections developed by local experts and quantify their impact on future pollutant concentrations. Moreover, we identify biases related to the implementation of regional scale emission projections over the study areas by comparing modeled pollutant concentrations between the fine and coarse scale simulations. We show that over urban areas with major regional contribution (e.g., the city of Stockholm) the bias due to coarse emission inventory may be significant and lead to policy misclassification. Our results stress the need to better understand the mechanism of bias propagation across the modeling scales in order to design more successful local-scale strategies. We find that the impact of climate change is spatially homogeneous in both regions, implying strong regional influence. The climate benefit for ozone (daily average and maximum) is up to −5 % for Paris and −2 % for Stockholm city. The joined climate benefit on PM2.5 and PM10 in Paris is between −10 and −5 % while for Stockholm we observe mixed trends up to 3 % depending on season and size class. In Stockholm, emission mitigation leads to concentration reductions up to 15 % for daily average and maximum ozone and 20 % for PM and through a sensitivity analysis we show that this response is entirely due to changes in emissions at the regional scale. On the contrary, over the city of Paris (VOC-limited photochemical regime), local mitigation of NOx emissions increases future ozone concentrations due to ozone titration inhibition. This competing trend between the respective roles of emission and climate change, results in an increase in 2050 daily average ozone by 2.5 % in Paris. Climate and not emission change appears to be the most influential factor for maximum ozone concentration over the city of Paris, which may be particularly interesting in a health impact perspective.

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Conducting Household Surveys on Reproductive Health in Urban Settings: Lessons From Karachi, Pakistan

10.21203/rs.3.rs-94413/v1 ◽

2020 ◽

Author(s):

Mir Baz Khan ◽

Sidrah Nausheen ◽

Imtiaz Hussain ◽

Kristy Hackett ◽

Zahra Kaneez ◽

...

Keyword(s):

Reproductive Health ◽

Urban Areas ◽

Large Scale ◽

Urban Environments ◽

Lessons Learned ◽

Geographical Information ◽

Health Study ◽

Computer Assisted ◽

Household Surveys ◽

Technical Problems

Abstract Background: Data collection is the most critical stage in any population health study and correctly implementing fieldwork enhances the quality of collected information. However, even the most carefully planned large-scale household surveys can encounter many context-specific issues. This paper reflected on our research team’s recent experiences of conducting surveys for a quasi-experimental evaluation of a reproductive health program in urban areas of Karachi, Pakistan. Methods: The study followed a three-stage random sampling design. Result: This paper has described the issues that were encountered around technical problems related to geographical information system (GIS) usage and computer assisted personal interviews (CAPI), household listing, interviewing respondents on sensitive topics and their expectations, and other field related concerns such as ensuring privacy etc. during the survey.Conclusion: The papers has also underscored on lessons learned from this process and presented some potential solutions for conducting future household surveys in similar urban environments.

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A VOXEL-BASED METADATA STRUCTURE FOR CHANGE DETECTION IN POINT CLOUDS OF LARGE-SCALE URBAN AREAS

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-iv-2-97-2018 ◽

2018 ◽

Vol IV-2 ◽

pp. 97-104

Author(s):

J. Gehrung ◽

M. Hebel ◽

M. Arens ◽

U. Stilla

Keyword(s):

Change Detection ◽

Urban Areas ◽

Laser Scanning ◽

Large Scale ◽

Point Clouds ◽

Urban Environments ◽

Detection Methods ◽

Planar Surfaces ◽

Occupancy Grids ◽

Speed Up

Mobile laser scanning has not only the potential to create detailed representations of urban environments, but also to determine changes up to a very detailed level. An environment representation for change detection in large scale urban environments based on point clouds has drawbacks in terms of memory scalability. Volumes, however, are a promising building block for memory efficient change detection methods. The challenge of working with 3D occupancy grids is that the usual raycasting-based methods applied for their generation lead to artifacts caused by the traversal of unfavorable discretized space. These artifacts have the potential to distort the state of voxels in close proximity to planar structures. In this work we propose a raycasting approach that utilizes knowledge about planar surfaces to completely prevent this kind of artifacts. To demonstrate the capabilities of our approach, a method for the iterative volumetric approximation of point clouds that allows to speed up the raycasting by 36 percent is proposed.

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The Use of Social Media for Urban Planning

Advances in Civil and Industrial Engineering - Technologies for Urban and Spatial Planning ◽

10.4018/978-1-4666-4349-9.ch006 ◽

2014 ◽

pp. 113-134 ◽

Cited By ~ 3

Author(s):

Fabian Neuhaus

Keyword(s):

Social Media ◽

Big Data ◽

Urban Areas ◽

Large Scale ◽

Urban Environments ◽

Data Systems ◽

User Management ◽

Social Nature ◽

User Data ◽

Use Of Social Media

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Indicators Framework for Sustainable Urban Design

Atmosphere ◽

10.3390/atmos11111143 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1143

Author(s):

Andrea López Chao ◽

Amparo Casares Gallego ◽

Vicente Lopez-Chao ◽

Alberto Alvarellos

Keyword(s):

Climate Change ◽

Urban Design ◽

Urban Areas ◽

Urban Environments ◽

Significant Feature ◽

Global Approach ◽

Climate Change Research ◽

Object Of Study ◽

The Impact ◽

Made In

Climate change and sustainability have recently been object of study due to the impact on the planet and on human activity of the first and the benefits that could derive from the efficiency of the second. Particularly, urban environments are locations that represent a high percentage of emissions of gases, waste, resources use and so forth. However, they are places where great changes can be made, in an attempt to accomplish the urgent challenge to adapt to current and projected rates of climate change. Research has shown that a fruitful approach to urban sustainability is to describe indicators that measure the effectiveness of current processes of urban infrastructures, analyze areas in need of improvement and measure the effect of any actions taken. The significant feature of this research relies on its global approach, considering both major worldwide used and less widely-spread frameworks and the analysis of the 32 selected tools and guidelines, including over 2000 indicators. The result is a proposed structure of 14 categories and 48 indicators, easily applicable in urban areas, that tries to fulfill basic aspects to obtain a general diagnosis of the sustainable nature of the urban environment, which can serve as support to detect the strongest and weakest areas in terms of their sustainability.

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