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The assessment of the number of people exposed to natural hazards, especially in countries with strong urban growth, is difficult to be updated at the same rate as land use develops. This paper presents a remote sensing-based procedure for quickly updating the assessment of the population exposed to natural hazards. A relationship between satellite nightlights intensity and urbanization density from global available cartography is first assessed when all data are available. This is used to extrapolate urbanization data at different time steps, updating exposure each time new nightlights intensity maps are available. To test the reliability of the proposed methodology, the number of people exposed to riverine flood in Italy is assessed, deriving a probabilistic relationship between DMSP nightlights intensity and urbanization density from the GUF database for the year 2011. People exposed to riverine flood are assessed crossing the population distributed on the derived urbanization density with flood hazard zones provided by ISPRA. The validation against reliable exposures derived from ISTAT data shows good agreement. The possibility to update exposure maps with a higher refresh rate makes this approach particularly suitable for applications in developing countries, where urbanization and population densities may change at a sub-yearly time scale.
Giorgio Boni; Silvia De Angeli; Angela Taramasso; Giorgio Roth. Remote Sensing-Based Methodology for the Quick Update of the Assessment of the Population Exposed to Natural Hazards. Remote Sensing 2020, 12, 3943 .
AMA StyleGiorgio Boni, Silvia De Angeli, Angela Taramasso, Giorgio Roth. Remote Sensing-Based Methodology for the Quick Update of the Assessment of the Population Exposed to Natural Hazards. Remote Sensing. 2020; 12 (23):3943.
Chicago/Turabian StyleGiorgio Boni; Silvia De Angeli; Angela Taramasso; Giorgio Roth. 2020. "Remote Sensing-Based Methodology for the Quick Update of the Assessment of the Population Exposed to Natural Hazards." Remote Sensing 12, no. 23: 3943.
The assessment of the number of people exposed to natural hazards, especially in countries with strong urban growth, is difficult to be updated at the same rate as land use develops. This paper presents a remote sensing based procedure for quick updating the assessment of the population exposed to natural hazards. A relationship between satellite nightlights intensity and urbanization density from global available cartography is first assessed when all data are available. This can be used to extrapolate urbanization data at different time steps, updating exposure each time new nightlights intensity maps are available. As reliability test for the proposed methodology, the number of people exposed to riverine flood in Italy is assessed, deriving a probabilistic relationship between DMSP nightlights intensity and urbanization density from GUF database for the year 2011. People exposed to riverine flood are assessed crossing the population distributed on the derived urbanization density with flood hazard zones provided by ISPRA. The validation on reliable exposures derived from ISTAT data shows good agreement. The possibility to update exposure maps with higher refresh rate makes this approach particularly suitable for applications in developing countries, where exposure may change at sub-yearly scale.
Giorgio Boni; Silvia De Angeli; Angela Celeste Taramasso; Giorgio Roth. Remote Sensing Based Methodology for the Quick Update of Population Exposed to Natural Hazards. 2020, 1 .
AMA StyleGiorgio Boni, Silvia De Angeli, Angela Celeste Taramasso, Giorgio Roth. Remote Sensing Based Methodology for the Quick Update of Population Exposed to Natural Hazards. . 2020; ():1.
Chicago/Turabian StyleGiorgio Boni; Silvia De Angeli; Angela Celeste Taramasso; Giorgio Roth. 2020. "Remote Sensing Based Methodology for the Quick Update of Population Exposed to Natural Hazards." , no. : 1.
Silvia De Angeli; Mirko D'Andrea; Giacomo Cazzola; Daniele Dolia; Enrico Duo; Nicola Rebora. Coastal Risk Assessment Framework: Comparison of modelled fluvial and marine inundation impacts, Bocca di Magra, Ligurian coast, Italy. Coastal Engineering 2018, 134, 229 -240.
AMA StyleSilvia De Angeli, Mirko D'Andrea, Giacomo Cazzola, Daniele Dolia, Enrico Duo, Nicola Rebora. Coastal Risk Assessment Framework: Comparison of modelled fluvial and marine inundation impacts, Bocca di Magra, Ligurian coast, Italy. Coastal Engineering. 2018; 134 ():229-240.
Chicago/Turabian StyleSilvia De Angeli; Mirko D'Andrea; Giacomo Cazzola; Daniele Dolia; Enrico Duo; Nicola Rebora. 2018. "Coastal Risk Assessment Framework: Comparison of modelled fluvial and marine inundation impacts, Bocca di Magra, Ligurian coast, Italy." Coastal Engineering 134, no. : 229-240.
Detection and characterization of territorial elements exposed to flood is a key component for flood risk analysis. Land-use description works well for small scales of representation but it becomes too coarse while increasing the scale. “Single-element” characterization is usually achieved through surveys, which become prohibitive as the amount of elements to be characterized increases. Mapping schemes represent a compromise between level of description and efforts for data collection. The basic idea is to determine the statistical distribution of building characteristics inside a homogeneous class starting from a sample area and to apply this distribution to the whole area, realizing a statistical extrapolation. An innovative approach was developed, merging the mapping scheme methodologies developed by the Global Earthquake Model [1] and Blanco–Vogt and Schanze [2], in which homogeneous classes are not development areas but building clusters. The approach was applied to the buildings in the Bisagno River floodplain, Genoa (Italy). Buildings were classified according to a building taxonomy. Once the percentage of basement presence was assigned to each class by surveying a limited subset of the exposed assets, a series of possible basement distributions was simulated to calculate the corresponding damage distributions for a real flood event. The total average damage obtained is very close to the refund claims, with a percentage error lower than 2%.
Silvia De Angeli; Fabio Dell’Acqua; Eva Trasforini. Application of an Earth-Observation-based building exposure mapping tool for flood damage assessment. E3S Web of Conferences 2016, 7, 05001 .
AMA StyleSilvia De Angeli, Fabio Dell’Acqua, Eva Trasforini. Application of an Earth-Observation-based building exposure mapping tool for flood damage assessment. E3S Web of Conferences. 2016; 7 ():05001.
Chicago/Turabian StyleSilvia De Angeli; Fabio Dell’Acqua; Eva Trasforini. 2016. "Application of an Earth-Observation-based building exposure mapping tool for flood damage assessment." E3S Web of Conferences 7, no. : 05001.
In the early months of 2015, destructive floods hit Malawi, causing deaths and economic losses. Flood risk assessment outcomes can be used to increase scientific-supported awareness of risk. The recent increase in availability of high resolution data such as TanDEM-X at 12m resolution makes possible the use of detailed physical based flood hazard models in risk assessment. Nonetheless the scale of hazard modelling still remains an issue, which requires a compromise between level of detail and computational efforts. This work presents two different approaches on hazard modelling. Both methods rely on 32-years of numeric weather re-analysis and rainfall-runoff transformation through a fully distributed WFLOW-type hydrological model. The first method, applied at national scale, uses fast post-processing routines, which estimate flood water depth at a resolution of about 1×1km. The second method applies a full 2D hydraulic model to propagate water discharge into the flood plains and best suites for small areas where assets are concentrated. At the 12m resolution, three hot spots with a model area of approximately 10×10 km are analysed. Flood hazard maps obtained with both approaches are combined with flood impact models at the same resolution to generate indicators for flood risk. A quantitative comparison of the two approaches is presented in order to show the effects of modelling scale on both hazard and impact losses.
Roberto Rudari; Joost Beckers; Silvia De Angeli; Lauro Rossi; Eva Trasforini. Impact of modelling scale on probabilistic flood risk assessment: the Malawi case. E3S Web of Conferences 2016, 7, 04015 .
AMA StyleRoberto Rudari, Joost Beckers, Silvia De Angeli, Lauro Rossi, Eva Trasforini. Impact of modelling scale on probabilistic flood risk assessment: the Malawi case. E3S Web of Conferences. 2016; 7 ():04015.
Chicago/Turabian StyleRoberto Rudari; Joost Beckers; Silvia De Angeli; Lauro Rossi; Eva Trasforini. 2016. "Impact of modelling scale on probabilistic flood risk assessment: the Malawi case." E3S Web of Conferences 7, no. : 04015.
During the autumn of 2011 two catastrophic, very intense rainfall events affected two different parts of the Liguria Region of Italy causing various flash floods. The first occurred in October and the second at the beginning of November. Both the events were characterized by very high rainfall intensities (> 100 mm h−1) that persisted on a small portion of territory causing local huge rainfall accumulations (> 400 mm 6 h−1). Two main considerations were made in order to set up this work. The first consideration is that various studies demonstrated that the two events had a similar genesis and similar triggering elements. The second very evident and coarse concern is that two main elements are needed to have a flash flood: a very intense and localized rainfall event and a catchment (or a group of catchments) to be affected. Starting from these assumptions we did the exercise of mixing the two flash flood ingredients by putting the rainfall field of the first event on the main catchment struck by the second event, which has its mouth in the biggest city of the Liguria Region: Genoa. A complete framework was set up to quantitatively carry out a “what if” experiment with the aim of evaluating the possible damages associated with this event. A probabilistic rainfall downscaling model was used to generate possible rainfall scenarios maintaining the main characteristics of the observed rainfall fields while a hydrological model transformed these rainfall scenarios in streamflow scenarios. A subset of streamflow scenarios is then used as input to a 2-D hydraulic model to estimate the hazard maps, and finally a proper methodology is applied for damage estimation. This leads to the estimation of the potential economic losses and of the risk level for the people that stay in the affected area. The results are interesting, surprising and in a way worrying: a rare but not impossible event (it occurred about 50 km away from Genoa) would have caused huge damages estimated between 120 and EUR 230 million for the affected part of the city of Genoa, Italy, and more than 17 000 potentially affected people.
Francesco Silvestro; Nicola Rebora; Lauro Rossi; Daniele Dolia; Simone Gabellani; Flavio Pignone; Eva Trasforini; Roberto Rudari; Silvia De Angeli; Cristiano Masciulli. What if the 25 October 2011 event that struck Cinque Terre (Liguria) had happened in Genoa, Italy? Flooding scenarios, hazard mapping and damage estimation. Natural Hazards and Earth System Sciences 2016, 16, 1737 -1753.
AMA StyleFrancesco Silvestro, Nicola Rebora, Lauro Rossi, Daniele Dolia, Simone Gabellani, Flavio Pignone, Eva Trasforini, Roberto Rudari, Silvia De Angeli, Cristiano Masciulli. What if the 25 October 2011 event that struck Cinque Terre (Liguria) had happened in Genoa, Italy? Flooding scenarios, hazard mapping and damage estimation. Natural Hazards and Earth System Sciences. 2016; 16 (8):1737-1753.
Chicago/Turabian StyleFrancesco Silvestro; Nicola Rebora; Lauro Rossi; Daniele Dolia; Simone Gabellani; Flavio Pignone; Eva Trasforini; Roberto Rudari; Silvia De Angeli; Cristiano Masciulli. 2016. "What if the 25 October 2011 event that struck Cinque Terre (Liguria) had happened in Genoa, Italy? Flooding scenarios, hazard mapping and damage estimation." Natural Hazards and Earth System Sciences 16, no. 8: 1737-1753.
During the autumn of 2011 two catastrophic very intense rainfall events affected two different parts of the Liguria Region of Italy causing various flash floods. The first occurred in October and the second at the beginning of November. They became two "school cases" studied by many scientists around the world and they awaken the interest of the local authorities and of the civil protection actors regarding these type of calamities. Due to the large amount of damages and the numerous victims, they caused a general increase of the sensibleness of the citizens of the stricken areas regarding the natural hazards. Two main considerations were done in order to set up this work. The first consideration is that various studies demonstrated that the two events had a similar genesis and similar triggering elements. The second very evident and coarse concern is that two main elements are needed to have a flash flood: a very intense and localized rainfall event and a catchment (or a group of catchments) to be affected. Starting from these assumptions we did the exercise of mixing the two flash floods ingredients by putting the rainfall field of the first event on the main catchment stroke by the second event that has its mouth in correspondence of the biggest city of the Liguria Region: Genova. A complete framework was set up to quantitatively carry out a "what if" experiment with the aim of evaluating the possible damages associated to this event. The approachcombines a probabilistic rainfall downscaling model, a hydrological model, a 2D hydraulic model and a proper methodology for damages estimation. This leads to the estimation of the potential economic losses and of the risk level for the people that stays in the affected area. The results are interesting, surprising and in such a way worrying: a rare but not impossible event (it occurred about 50 km away from Genoa) would have caused huge damages estimated between 120 and 230 million of euros for the affected part of the city of Genova, Italy and more than 17 000 potentially affected people.
Francesco Silvestro; Nicola Rebora; Lauro Rossi; Daniele Dolia; Simone Gabellani; Flavio Pignone; Eva Trasforini; Roberto Rudari; Silvia De Angeli; Cristiano Masciulli. What if the 25th October 2011 event that stroke Cinque Terre (Liguria) had happened in Genova, Italy? Flooding scenarios, hazard mapping and damages estimation. 2016, 2016, 1 -47.
AMA StyleFrancesco Silvestro, Nicola Rebora, Lauro Rossi, Daniele Dolia, Simone Gabellani, Flavio Pignone, Eva Trasforini, Roberto Rudari, Silvia De Angeli, Cristiano Masciulli. What if the 25th October 2011 event that stroke Cinque Terre (Liguria) had happened in Genova, Italy? Flooding scenarios, hazard mapping and damages estimation. . 2016; 2016 ():1-47.
Chicago/Turabian StyleFrancesco Silvestro; Nicola Rebora; Lauro Rossi; Daniele Dolia; Simone Gabellani; Flavio Pignone; Eva Trasforini; Roberto Rudari; Silvia De Angeli; Cristiano Masciulli. 2016. "What if the 25th October 2011 event that stroke Cinque Terre (Liguria) had happened in Genova, Italy? Flooding scenarios, hazard mapping and damages estimation." 2016, no. : 1-47.