SWOT River Database (SWORD)

VERSION NOTES: v17 versus v17b "Type" change for 1662 reaches and associated nodes globally. Please reference the Product Description Document for the "Type" identifier definition. Updates to reach and node lengths and distance-from-outlet variable to correct a bug in the node length calculation in select reaches (<2% of reaches were impacted globally). SWORD v17b is the official version for SWOT Version D RiverSP Vector Products. The project and public versions of SWORD were kept separate while algorithms were being developed in preparation for SWOT's launch in 2022. Now that the SWOT mission is here, the project version of SWORD is published as the public version which is why the version numbers jump after v2. The primary difference between the project and public versions of SWORD are extra "filler" variables in the NetCDF format that will be used for calculating discharge. For details on the filler variables please reference the Product Description Document provided with the downloads. If you use the SWORD Database in your work, please cite: Altenau et al., (2021) The Surface Water and Ocean Topography (SWOT) Mission River Database (SWORD): A Global River Network for Satellite Data Products. Water Resources Research. https://doi.org/10.1029/2021WR030054 You can also visit www.swordexplorer.com to explore the current version of SWORD before downloading. 1. Summary: The Surface Water and Ocean Topography (SWOT) satellite mission vastly expands observations of river water surface elevation (WSE), width, and slope. In order to facilitate a wide range of new analyses with flexibility, the SWOT mission provides a range of relevant data products. One product the SWOT mission provides are river vector products stored in shapefile format for each SWOT overpass (JPL Internal Document, 2020b). The SWOt River Database (SWORD) combines multiple global river- and satellite-related datasets to define the nodes and reaches that constitute SWOT river vector data products. SWORD provides high-resolution river nodes (200 m) and reaches (~10 km) in shapefile and netCDF formats with attached hydrologic variables (WSE, width, slope, etc.) as well as a consistent topological system for global rivers 30 m wide and greater. 2. Data Formats: The SWORD database is provided in netCDF, geopackage, and shapefile formats. All files start with a two-digit continent identifier ("af" – Africa, "as" – Asia / Siberia, "eu" – Europe / Middle East, "na" – North America, "oc" – Oceania, "sa" – South America). File syntax denotes the regional information for each file and varies slightly between netCDF and shapefile formats. NetCDF files are structured in 3 groups: centerlines, nodes, and reaches. The centerline group contains location information and associated reach and node ids along the original GRWL 30 m centerlines (Allen and Pavelsky, 2018). Node and reach groups contain hydrologic attributes at the ~200 m node and ~10 km reach locations (see description of attributes below). NetCDFs are distributed at continental scales with a filename convention as follows: [continent]_sword_v17.nc (i.e. na_sword_v17.nc). SWORD shapefiles consist of four main files (.dbf, .prj, .shp, .shx). There are separate shapefiles for nodes and reaches, where nodes are represented as ~200 m spaced points and reaches are represented as polylines. All shapefiles are in geographic (latitude/longitude) projection, referenced to datum WGS84. Shapefiles are split into HydroBASINS (Lehner and Grill, 2013) Pfafstetter level 2 basins (hbXX) for each continent with a naming convention as follows: [continent]_sword_[nodes/reaches]_hb[XX]_v17.shp (i.e. na_sword_nodes_hb74_v17.shp; na_sword_reaches_hb74_v17.shp). SWORD geopackage files are split into two files for nodes and reaches per continental region, where nodes are represented as 200 m spaced points and reaches are represented as polylines. All geopackage files are in geographic (latitude/longitude) projection, referenced to datum WGS84. Geopackage file names are distributed at continental scales and are defined by a two-digit identifier (Table 2): [continent]_sword_[nodes/reaches]_v17.gpkg (i.e. na_sword_nodes_v17.gpkg; na_sword_reaches_v17.gpkg). 3. Attribute Description: This list contains the primary attributes contained in the SWORD database. x: Longitude of the node or reach ranging from 180°E to 180°W (units: decimal degrees). y: Latitude of the node or reach ranging from 90°S to 90°N (units: decimal degrees). node_id: ID of each node. The format of the id is as follows: CBBBBBRRRRNNNT where C = Continent (the first number of the Pfafstetter basin code), B = Remaining Pfafstetter basin code up to level 6, R = Reach number (assigned sequentially within a level 6 basin starting at the downstream end working upstream), N = Node number (assigned sequentially within a reach starting at the downstream end working upstream), T = Type (1 – river, 3 – lake on river, 4 – dam or waterfall, 5 – unreliable topology, 6 – ghost node). node_length (node files only): Node length measured along the GRWL centerline points (units: meters). reach_id: ID of each reach. The format of the id is as follows: CBBBBBRRRRT where C = Continent (the first number of the Pfafstetter basin code), B = Remaining Pfafstetter basin codes up to level 6, R = Reach number (assigned sequentially within a level 6 basin starting at the downstream end working upstream, T = Type (1 – river, 3 – lake on river, 4 – dam or waterfall, 5 – unreliable topology, 6 – ghost reach). reach_length (reach files only): Reach length measured along the GRWL centerline points (units: meters). wse: Average water surface elevation (WSE) value for a node or reach. WSEs are extracted from the MERIT Hydro dataset (Yamazaki et al., 2019) and referenced to the EGM96 geoid (units: meters). wse_var: WSE variance along the GRWL centerline points used to calculate the average WSE for each node or reach (units: square meters). width: Average width for a node or reach (units: meters). width_var: Width variance along the GRWL centerline points used to calculate the average width for each node or reach (units: square meters). max_width: Maximum width value across the channel for each node or reach that includes island and bar areas (units: meters). facc: Maximum flow accumulation value for a node or reach. Flow accumulation values are extracted from the MERIT Hydro dataset (Yamazaki et al., 2019) (units: square kilometers). n_chan_max: Maximum number of channels for each node or reach. n_chan_mod: Mode of the number of channels for each node or reach. obstr_type: Type of obstruction for each node or reach based on the Globale Obstruction Database (GROD, Whittemore et al., 2020) and HydroFALLS data (http://wp.geog.mcgill.ca/hydrolab/hydrofalls). Obstr_type values: 0 - No Dam, 1 - Dam, 2 - Channel Dam, 3 - Lock, 4 - Low Permeable Dam, 5 - Waterfall. grod_id: The unique GROD ID for each node or reach with obstr_type values 1-4. hfalls_id: The unique HydroFALLS ID for each node or reach with obstr_type value 5. dist_out: Distance from the river outlet for each node or reach (units: meters). type: Type identifier for a node or reach: 1 – river, 2 – lake off river, 3 – lake on river, 4 – dam or waterfall, 5 – unreliable topology, 6 – ghost reach/node. lakeflag: GRWL water body identifier for each reach: 0 – river, 1 – lake/reservoir, 2 – canal, 3 – tidally influenced river. manual_add (node files only): Binary flag indicating whether the node was manually added to the public GRWL centerlines (Allen and Pavelsky, 2018). These nodes were originally given a width = 1, but have since been updated to have the reach width values. meand_len (node files only): Length of the meander that a node belongs to, measured from beginning of the meander to its end in meters. For nodes longer than one meander, the meander length will represent the average length of all meanders belonging to the node (units: meters). sinuosity (node files only): The total reach length the node belongs to divided by the Euclidean distance between the reach end points. slope (reach files only): Reach average slope calculated along the GRWL centerline points. Slopes are calculated using a linear regression (units: meters/kilometer). n_nodes (reach files only): Number of nodes associated with each reach. n_rch_up (reach files only): Number of upstream reaches for each reach. n_rch_down (reach files only): Number of downstream reaches for each reach. rch_id_up (reach files only): Reach IDs of the upstream neighboring reaches. rch_id_dn (reach files only): Reach IDs of the downstream neighboring reaches. swot_obs (reach files only): The maximum number of SWOT passes to intersect each reach during the 21 day orbit cycle. swot_orbits (reach files only): A list of the SWOT orbit tracks that intersect each reach during the 21 day orbit cycle. river_name: All river names associated with a node or reach. If there are multiple names for a node or reach they are listed in alphabetical order and separated by a semicolon. edit_flag: Numerical flag indicating the type of update applied to SWORD nodes or reaches from the previous version. Flag descriptions are listed in the Product Description Documentation included with the file downloads. trib_flag: Binary flag indicating if a large tributary not represented in SWORD is entering a node or reach. 0 - no tributary, 1 - tributary. 4. References: Allen, G. H., & Pavelsky, T. M. (2018). Global extent of rivers and streams. Science, 361(6402), 585-588. Altenau, E. H., Pavelsky, T. M., Durand, M. T., Yang X., Frasson, R. P. d. M., & Bendezu, L. (2021). The Surface Water and Ocean Topography (SWOT) Mission River Database (SWORD): A global river network for satellite data products". Water Resources Research. Biancamaria, S., Lettenmaier, D. P., & Pavelsky, T. M. (2016). The SWOT mission and its capabilities for land hydrology. In Remote Sensing and Water Resources (pp. 117-147). Springer, Cham. JPL Internal Document (2020b). Surface Water and Ocean Topography Mission Level 2 KaRIn high rate river single pass vector product, JPL D-56413, Rev. A, https://podaac-tools.jpl.nasa.gov/drive/files/misc/web/misc/swot_mission_docs/pdd/D-56413_SWOT_Product_Description_L2_HR_RiverSP_20200825a.pdf Lehner, B., Grill G. (2013): Global river hydrography and network routing: baseline data and new approaches to study the world's large river systems. Hydrological Processes, 27(15): 2171–2186. Data is available at www.hydrosheds.org. Tessler, Z. D., Vörösmarty, C. J., Grossberg, M., Gladkova, I., Aizenman, H., Syvitski, J. P. M., & Foufoula-Georgiou, E. (2015). Profiling risk and sustainability in coastal deltas of the world. Science, 349(6248), 638-643. Whittemore, A., Ross, M. R., Dolan, W., Langhorst, T., Yang, X., Pawar, S., Jorissen, M., Lawton, E., Januchowski-Hartley, S., & Pavelsky, T. (2020). A Participatory Science Approach to Expanding Instream Infrastructure Inventories. Earth's Future, 8(11), e2020EF001558. Yamazaki, D., Ikeshima, D., Sosa, J., Bates, P. D., Allen, G., & Pavelsky, T. (2019). MERIT Hydro: A high-resolution global hydrography map based on latest topography datasets. Water Resources Research. https://doi.org/10.1029/2019WR024873. Yang, X., Pavelsky, T. M., Allen, G. H. (2019). The past and future of global river ice. Nature. SWOT Orbits: https://www.aviso.altimetry.fr/en/missions/future-missions/swot/orbit.html HydroFALLS: http://wp.geog.mcgill.ca/hydrolab/hydrofalls/版本说明： v17与v17b对比 全球范围内1662个河段（reach）及其关联节点（node）的"Type"字段已完成修改，请参考《产品说明文档》以了解"Type"标识符的定义。 本次更新修复了部分河段的节点长度计算错误，同步更新了河段、节点长度及距河口距离变量（全球范围内受影响河段占比不足2%）。 SWORD v17b是SWOT（Surface Water and Ocean Topography，水面与海洋地形任务）版本D RiverSP矢量产品的官方版本。 在2022年SWOT任务发射筹备期间，SWORD的项目版本与公开版本曾相互独立。随着SWOT任务正式启动，SWORD的项目版本现已作为公开版本发布，这也是v2之后版本号大幅跃升的原因。项目版本与公开版本的核心差异在于NetCDF（网络通用数据格式）中新增了用于计算流量的"填充变量"，若需了解填充变量的详细信息，请参考下载包附带的《产品说明文档》。 若您在研究中使用SWORD数据库，请引用：Altenau等人（2021）发表于《Water Resources Research》的《The Surface Water and Ocean Topography (SWOT) Mission River Database (SWORD): A Global River Network for Satellite Data Products》，DOI：10.1029/2021WR030054。 您也可在下载前访问www.swordexplorer.com，浏览SWORD的当前版本。 1. 总结 SWOT（Surface Water and Ocean Topography，水面与海洋地形任务）卫星任务极大拓展了河流水面高程（Water Surface Elevation, WSE）、宽度与坡度的观测覆盖范围。为支持灵活多样的新型分析，SWOT任务提供了一系列相关数据产品。其中一类产品为每个SWOT过境场景生成的shapefile（形状文件）格式河流矢量产品（JPL内部文档，2020b）。SWOT河流数据库（SWOt River Database, SWORD）整合了多套全球河流与卫星相关数据集，用于定义构成SWOT河流矢量产品的节点（node）与河段（reach）。SWORD以shapefile与NetCDF格式提供分辨率为200米的河道节点与约10公里的河段数据，附带水文变量（如WSE、宽度、坡度等），并为宽度≥30米的全球河流构建了统一的拓扑系统。 2. 数据格式 SWORD数据库提供NetCDF、geopackage与shapefile三种格式。所有文件名均以两位大陆标识符开头："af"——非洲，"as"——亚洲/西伯利亚，"eu"——欧洲/中东，"na"——北美洲，"oc"——大洋洲，"sa"——南美洲。文件名语法用于标识文件所属区域，NetCDF与shapefile格式的命名规则略有差异。 NetCDF文件分为3个组：中心线（centerlines）、节点（nodes）与河段（reaches）。中心线组包含原始GRWL（全球河道中心线数据集）30米中心线的位置信息及关联的河段与节点ID（Allen和Pavelsky，2018）。节点与河段组包含约200米分辨率节点和约10公里分辨率河段的水文属性（详见下文属性说明）。NetCDF文件按大陆尺度分发，命名规则为：[continent]_sword_v17.nc（例如na_sword_v17.nc）。 SWORD的shapefile包含4个核心文件：.dbf、.prj、.shp、.shx。节点与河段分别拥有独立的shapefile：节点为间距约200米的点要素，河段为多段线要素。所有shapefile均采用地理（纬度/经度）投影，基准面为WGS84。针对每个大陆，shapefile按HydroBASINS（Lehner和Grill，2013）的Pfafstetter二级流域（hbXX）拆分，命名规则为：[continent]_sword_[nodes/reaches]_hb[XX]_v17.shp（例如na_sword_nodes_hb74_v17.shp；na_sword_reaches_hb74_v17.shp）。 SWORD的geopackage文件按大陆区域拆分为节点与河段两个文件：节点为间距200米的点要素，河段为多段线要素。所有geopackage文件均采用地理（纬度/经度）投影，基准面为WGS84。geopackage文件按大陆尺度命名，由两位标识符定义（见表2），命名规则为：[continent]_sword_[nodes/reaches]_v17.gpkg（例如na_sword_nodes_v17.gpkg；na_sword_reaches_v17.gpkg）。 3. 属性说明 下表列出了SWORD数据库包含的核心属性。 x：节点或河段的经度，范围为180°E至180°W，单位为十进制度。 y：节点或河段的纬度，范围为90°S至90°N，单位为十进制度。 node_id：每个节点的ID，格式为CBBBBBRRRRNNNT，其中：C为大陆代码（Pfafstetter流域代码的首位数字）；B为剩余的Pfafstetter流域代码（最高至6级）；R为河段编号（在6级流域内从下游向上游依次编号）；N为节点编号（在河段内从下游向上游依次编号）；T为类型（1——河流，3——河道内湖泊，4——大坝或瀑布，5——不可靠拓扑，6——幽灵节点）。 node_length（仅节点文件包含）：沿GRWL中心线点测量的节点长度，单位为米。 reach_id：每个河段的ID，格式为CBBBBBRRRRT，其中：C为大陆代码（Pfafstetter流域代码的首位数字）；B为剩余的Pfafstetter流域代码（最高至6级）；R为河段编号（在6级流域内从下游向上游依次编号）；T为类型（1——河流，3——河道内湖泊，4——大坝或瀑布，5——不可靠拓扑，6——幽灵河段）。 reach_length（仅河段文件包含）：沿GRWL中心线点测量的河段长度，单位为米。 wse：节点或河段的平均水面高程（Water Surface Elevation, WSE），数据取自MERIT Hydro数据集（Yamazaki等，2019），基准为EGM96大地水准面，单位为米。 wse_var：用于计算节点或河段平均WSE的GRWL中心线点的WSE方差，单位为平方米。 width：节点或河段的平均宽度，单位为米。 width_var：用于计算节点或河段平均宽度的GRWL中心线点的宽度方差，单位为平方米。 max_width：节点或河段的河道最大宽度（包含岛屿与沙洲区域），单位为米。 facc：节点或河段的最大汇流面积，数据取自MERIT Hydro数据集（Yamazaki等，2019），单位为平方千米。 n_chan_max：节点或河段的最大河道数量。 n_chan_mod：节点或河段河道数量的众数。 obstr_type：基于全球障碍物数据库（Globale Obstruction Database, GROD，Whittemore等，2020）与HydroFALLS数据（http://wp.geog.mcgill.ca/hydrolab/hydrofalls）定义的节点或河段障碍物类型，取值为：0——无大坝，1——大坝，2——河道型大坝，3——船闸，4——低渗透性大坝，5——瀑布。 grod_id：obstr_type取值为1-4的节点或河段的唯一GROD标识符。 hfalls_id：obstr_type取值为5的节点或河段的唯一HydroFALLS标识符。 dist_out：节点或河段距河流河口的距离，单位为米。 type：节点或河段的类型标识符：1——河流，2——河道外湖泊，3——河道内湖泊，4——大坝或瀑布，5——不可靠拓扑，6——幽灵河段/节点。 lakeflag：每个河段的GRWL水体标识符：0——河流，1——湖泊/水库，2——运河，3——受潮汐影响的河流。 manual_add（仅节点文件包含）：二进制标记，用于标识该节点是否为手动添加至公开GRWL中心线的节点（Allen和Pavelsky，2018）。此类节点最初被赋值宽度为1，后续已更新为对应河段的宽度值。 meand_len（仅节点文件包含）：节点所属河曲的长度，从河曲起点至终点的测量值，单位为米。若节点跨越多个河曲，则该值为节点所属所有河曲的平均长度，单位为米。 sinuosity（仅节点文件包含）：节点所属河段的总长度与河段端点间欧氏距离的比值。 slope（仅河段文件包含）：沿GRWL中心线点计算的河段平均坡度，采用线性回归方法求解，单位为米/千米。 n_nodes（仅河段文件包含）：每个河段关联的节点数量。 n_rch_up（仅河段文件包含）：每个河段的上游河段数量。 n_rch_down（仅河段文件包含）：每个河段的下游河段数量。 rch_id_up（仅河段文件包含）：上游相邻河段的ID。 rch_id_dn（仅河段文件包含）：下游相邻河段的ID。 swot_obs（仅河段文件包含）：21天轨道周期内，与每个河段相交的SWOT过境次数的最大值。 swot_orbits（仅河段文件包含）：21天轨道周期内，与每个河段相交的SWOT轨道轨迹列表。 river_name：与节点或河段关联的所有河流名称。若存在多个名称，则按字母顺序排列并以分号分隔。 edit_flag：数值标记，用于标识SWORD节点或河段相较于上一版本的更新类型。标记的详细说明请参考下载包附带的《产品说明文档》。 trib_flag：二进制标记，用于标识是否存在未在SWORD中体现的大型支流汇入节点或河段。0——无支流汇入，1——有支流汇入。 4. 参考文献 Allen, G. H. 与 Pavelsky, T. M.（2018）。全球河流与溪流分布范围。《Science》，361(6402)，585-588。 Altenau, E. H. 等（2021）。《水面与海洋地形（SWOT）任务河流数据库（SWORD）：面向卫星数据产品的全球河网》。《Water Resources Research》。 Biancamaria, S.、Lettenmaier, D. P. 与 Pavelsky, T. M.（2016）。SWOT任务及其在陆地水文学中的应用能力。收录于《Remote Sensing and Water Resources》（第117-147页）。Springer Cham出版社。 JPL内部文档（2020b）。《水面与海洋地形任务二级KaRIn高速河道单次过境矢量产品》，JPL D-56413，修订版A，链接：https://podaac-tools.jpl.nasa.gov/drive/files/misc/web/misc/swot_mission_docs/pdd/D-56413_SWOT_Product_Description_L2_HR_RiverSP_20200825a.pdf。 Lehner, B. 与 Grill, G.（2013）。全球河流水文与网络汇流：研究全球大型河系的基础数据与新方法。《Hydrological Processes》，27(15)：2171–2186。数据可从www.hydrosheds.org获取。 Tessler, Z. D. 等（2015）。全球沿海三角洲的风险与可持续性分析。《Science》，349(6248)，638-643。 Whittemore, A. 等（2020）。拓展河道基础设施清单的参与式科学方法。《Earth's Future》，8(11)，e2020EF001558。 Yamazaki, D. 等（2019）。MERIT Hydro：基于最新地形数据集的高分辨率全球水文地图。《Water Resources Research》，DOI：10.1029/2019WR024873。 Yang, X.、Pavelsky, T. M. 与 Allen, G. H.（2019）。全球河冰的过去与未来。《Nature》。 SWOT轨道：https://www.aviso.altimetry.fr/en/missions/future-missions/swot/orbit.html HydroFALLS：http://wp.geog.mcgill.ca/hydrolab/hydrofalls/