Automatic Flood Duration Estimation Based on Multi-Sensor Satellite Data

Abstract

Flood duration is a crucial parameter for disaster impact assessment as it can directly influence the degree of economic losses and damage to structures. It also provides an indication of the spatio-temporal persistence and the evolution of inundation events. Thus, it helps gain a better understanding of hydrological conditions and surface water availability and provides valuable insights for land-use planning. The objective of this work is to develop an automatic procedure to estimate flood duration and the uncertainty associated with the use of multi-temporal flood extent masks upon which the procedure is based. To ensure sufficiently high observation frequencies, data from multiple satellites, namely Sentinel-1, Sentinel-2, Landsat-8 and TerraSAR-X, are analyzed. Satellite image processing and analysis is carried out in near real-time with an integrated system of dedicated processing chains for the delineation of flood extents from the range of aforementioned sensors. The skill of the proposed method to support satellite-based emergency mapping activities is demonstrated on two cases, namely the 2019 flood in Sofala, Mozambique and the 2017 flood in Bihar, India.

Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent

“…e equation for between-class variance is shown in equation (3). e between-class variance formula includes the multiplication of background and foreground weight with a square difference of the mean background pixels, μ b , with the mean of the foreground pixels, μ f [29]:…”

“…Flood mapping is one of the sources of information used by decision makers, planners, and response teams to mitigate flood disasters. Multitemporal coverage of large areas using Earth observation satellites is widely used to observe differences in land cover before, during, and after flood events [3][4][5][6]. Large-scale information of flood situations can be retrieved from optical and radar satellite images.…”

A Visualization Tool for Flood Dynamics Monitoring Using a Graph-Based Approach

“…While selecting cases for upscaling, the following criteria were considered: (1) The flood area should be about 100 times larger than in the previous prove of concept [9]; (2) the images should fall completely within single Sentinel-1 captures in order to avoid stitching; (3) at least one external flood extent map should be available for comparison; (4) the cases should be different in nature to detect possible different behaviors. With these criteria, two recent floods were chosen, namely a flood in Mozambique and a flood in India, which both took place in the year 2019.…”

“…These products fail to provide information on flood dynamics, which is crucial for several applications. For example, flood duration can be linked directly to the degree of economic losses and damages to structures [1][2][3][4] in the context of disaster impact assessment (emergency relief, damage assessment, insurance claims . .…”

Automatic Near-Real Time Flood Extent and Duration Mapping based On Multi-Sensor Earth Observation Data

“…In order to provide emergency managers with spatiotemporal information about the stability and the evolution of an inundation event or to assess the damage related to flood events, the estimation of flood duration is a very crucial parameter. In order to estimate the flood duration on a regular basis in NRT in case of disaster situations a fully automated approach is developed [3] and integrated into the flood monitoring system.…”