METEOR: Nepal Flood Hazard Map - Pluvial for return periods of 1 in 5, 10, 20, 50, 75, 100, 200, 250, 500 and 1000 years

Data Description Flood Hazard Map showing Pluvial modelled water depth for flood events of different return periods for the country of Nepal. Pluvial flooding (local surface water flooding from extreme rainfall) has been simulated and can be displayed in a GIS system. Depths are shown in meters. Note that one would not expect all the displayed flooding to happen at the same time; rather, the data show the maximum water depth that would be expected if a flood event of the specified return period were occurring at that location. Another way of expressing this is to say that the data show the probability of experiencing a given water depth within a single year; i.e. depths shown by the ‘1-in-100 year’ layer have a 1-in-100 (or 1%) chance of occurrence in any given year. The data has been produced using the Fathom global flood hazard modelling framework (a development of Sampson et al., 2015 and Smith et al., 2015). The model uses the MERIT global DEM, and hydrography for elevation and river network data sources respectively (Yamazaki et al., 2017; Yamazaki et al., 2019). The framework automatically constructs flood models across a specified region, using the two-dimensional shallow water equations to simulate the behavior of floodwaters during the modelled flood events. The framework produces maps of flood depths at 3 arcsecond (~90m) spatial resolution for a specified range of return periods. For a detailed technical description of the methods, please see the open-access academic papers listed below. Given that the modelling framework used to create this data is semi-autonomous and uses data available at the regional to global scale, its accuracy is limited by the quality of this input data and the simplified range of processes it can represent. While the data is suitable for providing guidance at the regional scale, it is not recommended to use the data for detailed local scale assessments or engineering purposes. Data Producer Attribution SSBN Ltd (Fathom) Project Attribution The data was generated by SSBN Ltd (Fathom) as part of the Modelling Exposure Through Earth Observation Routines (METEOR): EO-based Exposure, Nepal and Tanzania project, a £2.8m project co-funded through the UK Space Agency’s International Partnership Programme (IPP) Call 2 as part of the Global Challenges Research Fund (GCRF) from the UK Government’s Official Development Assistance (ODA) commitment. Data Format GeoTIFF Data Visualisation GIS software. Suggested colour (6-digit hexadecimal format) for water depth ranges: <1m (#FA954D); <2m (#DBDBFF); <3m (#B8B8FF); <4m (#8C8CEA); <5m (#7171FF); 5m (#4D4DFF) and Permanent (#E771EB) Spatial Resolution 3 arcseconds (~90m) Geographic Coordinate Reference System WGS84 (EPSG:4326) Referenced Open Access Academic Papers Sampson, C.C., Smith, A.M., Bates, P.D., Neal, J.C., Alfieri, L. & Freer, J.E. (2015) A high-resolution global flood hazard model, Water Resources Research, 51, 7358–7381. https://doi.org/10.1002/2015WR016954 Smith, A., Sampson, C. & Bates, P. (2015) Regional flood frequency analysis at the global scale, Water Resources Research, 51, 539–553. https://doi.org/10.1002/2014WR015814 Yamazaki, D., Ikeshima, D., Tawatari, R., Yamaguchi, T., O'Loughlin, F., Neal, J.C., Sampson, C.C., Kanae, S. & Bates, P.D. (2017) A high-accuracy map of global terrain elevations, Geophys. Res. Lett., 44, 5844–5853, https://doi.org/10.1002/2017GL072874 Yamazaki, D., Ikeshima, D., Sosa, J., Bates, P.D., Allen, G.H., & Pavelsky, T. M. (2019) MERIT Hydro: a high-resolution global hydrography map based on latest topography dataset. Water Resources Research, 55, 5053–5073. https://doi.org/10.1029/2019WR024873 Contact [e-mail]数据集说明 本数据集为尼泊尔全境不同重现期洪水事件的雨洪（Pluvial）模拟水深灾害地图。 雨洪（即极端降雨引发的局地地表积水灾害）已通过模拟生成，可在地理信息系统（Geographic Information System，GIS）中可视化展示，水深单位为米。请注意，地图中展示的积水不会同时全部出现；本数据集呈现的是，当某一地点发生指定重现期洪水事件时，该位置可能出现的最大水深。换而言之，该数据集展示了单一年份内出现特定水深的概率：例如，“百年一遇”图层对应的水深，在任意单一年份内发生的概率为1%（即1/100）。 本数据集基于Fathom全球洪水灾害模拟框架开发（该框架由Sampson等人2015年与Smith等人2015年的研究发展而来）。该模型分别采用MERIT全球数字高程模型（Digital Elevation Model，DEM）与水文地形数据作为高程与河网数据源（Yamazaki等，2017；Yamazaki等，2019）。该框架可针对指定区域自动构建洪水模型，通过二维浅水方程模拟目标洪水事件中洪水的演进过程，并生成指定重现期范围内、空间分辨率为3角秒（约90米）的洪水水深分布图。如需了解方法的详细技术说明，请参阅下文列出的开放获取学术论文。 由于本数据集所采用的模拟框架为半自主式，且使用区域至全球尺度的公开数据，其精度受输入数据源质量与模型可表征过程的简化程度限制。本数据集仅适用于区域尺度的辅助分析，不建议将其用于局地精细化评估或工程用途。 ## 数据生产方说明 SSBN有限公司（Fathom） ## 项目说明 本数据集由SSBN有限公司（Fathom）为“基于对地观测（Earth Observation，EO）流程的暴露度建模（METEOR）：尼泊尔与坦桑尼亚基于EO的暴露度”项目生成。该项目总经费280万英镑，由英国政府官方发展援助（Official Development Assistance，ODA）框架下的全球挑战研究基金（Global Challenges Research Fund，GCRF）资助，通过英国航天局（UK Space Agency）国际合作计划（International Partnership Programme，IPP）第二轮征集项目立项。 ## 数据格式 GeoTIFF ## 数据可视化 可通过地理信息系统（GIS）软件可视化。建议水深区间对应的6位十六进制颜色码如下：水深<1米（#FA954D）；水深<2米（#DBDBFF）；水深<3米（#B8B8FF）；水深<4米（#8C8CEA）；水深<5米（#7171FF）；水深≥5米（#4D4DFF）；永久水体（#E771EB） ## 空间分辨率 3角秒（约90米） ## 地理坐标参考系统 WGS84（EPSG:4326） ## 引用的开放获取学术论文 1. Sampson, C.C., Smith, A.M., Bates, P.D., Neal, J.C., Alfieri, L. & Freer, J.E. (2015) A high-resolution global flood hazard model, Water Resources Research, 51, 7358–7381. https://doi.org/10.1002/2015WR016954 2. Smith, A., Sampson, C. & Bates, P. (2015) Regional flood frequency analysis at the global scale, Water Resources Research, 51, 539–553. https://doi.org/10.1002/2014WR015814 3. Yamazaki, D., Ikeshima, D., Tawatari, R., Yamaguchi, T., O'Loughlin, F., Neal, J.C., Sampson, C.C., Kanae, S. & Bates, P.D. (2017) A high-accuracy map of global terrain elevations, Geophys. Res. Lett., 44, 5844–5853, https://doi.org/10.1002/2017GL072874 4. Yamazaki, D., Ikeshima, D., Sosa, J., Bates, P.D., Allen, G.H., & Pavelsky, T. M. (2019) MERIT Hydro: a high-resolution global hydrography map based on latest topography dataset. Water Resources Research, 55, 5053–5073. https://doi.org/10.1029/2019WR024873 ## 联系方式 [e-mail]