The Flood Hazard: Frequency and Distribution layer indicates the relative distribution and frequency of flood hazard. Global Flood Hazard Frequency and Distribution is a 2.5 minute grid derived from a global listing of extreme flood events between 1985 and 2003 (poor or missing data in the early/mid 1990s) compiled by Dartmouth Flood Observatory and georeferenced to the nearest degree. The resultant flood frequency grid was then classified into 10 classes of approximately equal number of grid cells. The greater the grid cell value in the final data set, the higher the relative frequency of flood occurrence.
The purpose of this layer is to provide a means of assessing the relative distribution and frequency of global flood hazard.
References: doi:10.7927/H4668B3D
The Flood Hazard: Mortality Risk layer indicates the global flood mortality risks and distribution between 1985 and 2003. The information displayed in Worldview/Global Imagery Browse Services (GIBS) reflects the decile within which the risk lies, ranging from low to high mortality risk: 1st to 10th decile.
Global Flood Mortality Risks and Distribution is a 2.5 minute grid of global flood mortality risks. Gridded Population of the World, Version 3 (GPWv3) data provided a baseline population per grid cell from which to estimate potential mortality risks due to flood hazard. Mortality loss estimates per flood event are calculated using regional, hazard-specific mortality records of the Emergency Events Database (EM-DAT) that span the 20 years between 1981 and 2000. Data regarding the frequency and distribution of flood hazard are obtained from the Global Flood Hazard Frequency and Distribution data set. In order to more accurately reflect the confidence associated with the data and the procedures, the potential mortality estimate range is classified into deciles, 10 classes of increasing hazard with an approximately equal number of grid cells per class, producing a relative estimate of flood-based mortality risks.
References: doi:10.7927/H42F7KCP
The Flood Hazard: Economic Risk layer indicates the the proportional economic impacts of global flood hazard between 1985 and 2003. The information displayed in Worldview/Global Imagery Browse Services (GIBS) reflects the decile within which the risk lies, ranging from low to high economic risk: 1st to 10th decile.
Global Flood Proportional Economic Loss Risk Deciles is a 2.5 minute grid of flood hazard economic loss as proportions of Gross Domestic Product (GDP) per analytical unit. Estimates of GDP at risk are based on regional economic loss rates derived from historical records of the Emergency Events Database (EM-DAT). Loss rates are weighted by the hazard's frequency and distribution. The vulnerability weights are based on historical economic losses in previous disasters. The economic loss risks are applied to GDP per unit area exposure to obtain economic loss risks. The weights are an aggregate index relative to losses within each region and country wealth class (classifications based on 2000 GDP) over the 20-year period from 1981 –2000. This index is then normalized by GDP. The methodology of Sachs et al. (2003) is followed to determine baseline estimates of GDP per grid cell. To better reflect the confidence surrounding the data and procedures, the range of proportionalities is classified into deciles, 10 classes of an approximately equal number of grid cells of increasing risk.
References: doi:10.7927/H4XS5S9Q