GEE数据集——全球SWOT 河流数据库（SWORD）河流水面高程、宽度和坡度测量数据集

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发布于 2024-06-12 08:21:26

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发布于 2024-06-12 08:21:26

SWOT 河流数据库（SWORD）地表水和海洋地形（SWOT）卫星任务于 2022 年 12 月成功发射，通过提供大量的河流水面高程、宽度和坡度测量数据集，彻底改变了我们观测河流的能力。为了最大限度地提高这些数据的实用性和灵活性，SWOT 任务提供了各种数据产品，包括每个 SWOT 立交桥的 shapefile 格式河流矢量数据。这些矢量产品为河流系统的多时分析提供了巨大的潜力，使研究人员能够跟踪河流特征随时间的变化。

为了能够进行此类分析，在 SWOT 启动之前定义一致的河流河段和节点至关重要。这可确保来自不同河段的数据能够准确分配和比较。SWOT 河流数据库（SWORD）将与河流和卫星观测有关的多个全球数据集结合在一起，从而发挥了这一关键作用。SWORD 以 shapefile 和 netCDF 两种格式提供了高分辨率河流节点（沿河流中心线每 200 米间隔）和河段（约 10 公里的河段）的标准化框架。这些节点和河段附有一系列相关的水文变量，如水面高程、宽度、坡度以及河流障碍物、流量累积等信息。这个全面的数据集涵盖了全球 30 米宽及以上的河流，使研究人员能够对河流系统进行深入分析，并充分利用 SWOT 数据的潜力。

SWORD 整合了多个现有全球水文地理数据集的数据，包括全球陆地卫星河宽（GRWL）、MERIT Hydro、HydroBASINS 和全球河流阻塞数据库（GROD）。它为每个节点和河段提供了丰富的属性，如

位置：纬度/经度坐标、河段边界。物理特征：水面高程、宽度、坡度、流量累积、渠道数量、障碍类型（水坝、瀑布等）。水文模型：各种排泄量估算模型（如 MetroMan、BAM、HiVDI）的参数及相关不确定性。 SWOT 观测信息：在 21 天的轨道周期内，SWOT 经过的次数以及与每个河段交汇的具体轨道轨迹。其他属性：河流名称、冰覆盖标志、支流标志以及表示潜在拓扑不一致或数据限制的质量标志。

数据属性

Attribute	Description	Units
x	Longitude of each node ranging from 180°E to 180°W	decimal degrees
y	Latitude of each node, ranging from 90°S to 90°N	decimal degrees
node_id	Unique identifier for each node, formatted as: CBBBBBRRRRNNNT (C: Continent, B: Pfafstetter basin codes, R: Reach ID, N: Node ID within reach, T: Type)	none
node_length	Length of the node measured along the high-resolution centerline points	meters
reach_id	ID of the reach associated with each node, formatted as: CBBBBBRRRRT (C: Continent, B: Pfafstetter basin codes, R: Reach ID, T: Type)	none
wse	Average water surface elevation of the node	meters
wse_var	Variance of water surface elevation along the high-resolution centerline points used to calculate the average water surface elevation for each node	meters^2
width	Average width of the node	meters
width_var	Variance of width along the high-resolution centerline points used to calculate the average width for each node	meters^2
n_chan_max	Maximum number of channels observed within the node	none
n_chan_mod	Mode (most frequent) number of channels observed within the node	none
obstr_type	Type of obstruction at the node based on GROD and HydroFALLS databases: 0 - No Dam, 1 - Dam, 2 - Lock, 3 - Low Permeable Dam, 4 - Waterfall	none
grod_id	Unique GROD ID for nodes with obstr_type values 1-3	none
hfalls_id	Unique HydroFALLS ID for nodes with obstr_type value 4	none
dist_out	Distance from the river outlet to the node	meters
type	Node type identifier: 1 - River, 3 - Lake on river, 4 - Dam/waterfall, 5 - Unreliable topology, 6 - Ghost node	none
facc	Maximum flow accumulation value for the node	kilometers^2
lakeflag	GRWL water body identifier: 0 - River, 1 - Lake/reservoir, 2 - Canal, 3 - Tidally influenced river	none
max_width	Maximum width across the channel for the node, including islands and bars	meters
river_name	All river names associated with the node (separated by semicolons if multiple)	none
sinuosity	Ratio of total reach length to the straight-line distance between reach endpoints, indicating the degree of meandering	none
meand_len	Average length of meanders the node belongs to	meters
manual_add	Binary flag indicating if the node was manually added to GRWL centerlines (1) or not (0)	none
trib_flag	Binary flag indicating if a large tributary not in SWORD enters the node (1) or not (0)	none

Attribute	Description	Units
x	Longitude of the reach center point (ranging from 180°E to 180°W)	decimal degrees
y	Latitude of the reach center point (ranging from 90°S to 90°N)	decimal degrees
reach_id	Unique identifier for each reach, formatted as: CBBBBBRRRRT (C: Continent, B: Pfafstetter basin codes, R: Reach ID, T: Type)	none
reach_length	Length of the reach measured along the high-resolution centerline points	meters
wse	Average water surface elevation of the reach	meters
wse_var	Variance of water surface elevation along the high-resolution centerline points used to calculate the average water surface elevation for each reach	meters^2
width	Average width of the reach	meters
width_var	Variance of width along the high-resolution centerline points used to calculate the average width for each reach	meters^2
n_nodes	Number of nodes associated with the reach	none
n_chan_max	Maximum number of channels observed within the reach	none
n_chan_mod	Mode (most frequent) number of channels observed within the reach	none
obstr_type	Type of obstruction within the reach based on GROD and HydroFALLS databases: 0 - No Dam, 1 - Dam, 2 - Lock, 3 - Low Permeable Dam, 4 - Waterfall	none
grod_id	Unique GROD ID for reaches with obstr_type values 1-3	none
hfalls_id	Unique HydroFALLS ID for reaches with obstr_type value 4	none
slope	Average slope of the reach calculated along the high-resolution centerline points	m/km
dist_out	Distance from the river outlet to the reach	meters
n_rch_up	Number of upstream reaches connected to this reach	none
n_rch_down	Number of downstream reaches connected to this reach	none
rch_id_up	IDs of the upstream reaches connected to this reach	none
rch_id_dn	IDs of the downstream reaches connected to this reach	none
lakeflag	GRWL water body identifier: 0 - River, 1 - Lake/reservoir, 2 - Canal, 3 - Tidally influenced river	none
max_width	Maximum width across the channel for the reach, including islands and bars	meters
type	Reach type identifier: 1 - River, 3 - Lake on river, 4 - Dam/waterfall, 5 - Unreliable topology, 6 - Ghost reach	none
facc	Maximum flow accumulation value for the reach	kilometers^2
swot_obs	Maximum number of SWOT passes intersecting the reach during the 21-day orbit cycle	none
swot_orbits	List of SWOT orbit track numbers that intersect the reach during the 21-day cycle	none
river_name	All river names associated with the reach (separated by semicolons if multiple)	none
trib_flag	Binary flag indicating if a large tributary not in SWORD enters the reach (1) or not (0)	none

数据处理

海域和节点形状文件数据集已下载压缩，并作为单独的形状文件上传。然后合并文件夹资产，创建单一的节点和河段文件。形状文件中的属性按原样保留。

数据引用

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

Elizabeth H. Altenau, Tamlin M. Pavelsky, Michael T. Durand, Xiao Yang, Renato P. d. M. Frasson, & Liam Bendezu. (2023). SWOT River Database (SWORD) (Version v16) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.10013982

代码

var nodes_merged = ee.FeatureCollection("projects/sat-io/open-datasets/SWORD/nodes_merged");
var reaches_merged = ee.FeatureCollection("projects/sat-io/open-datasets/SWORD/reaches_merged");

// Define different styles for each FeatureCollection
var nodeStyle = {
  color: 'red',
  width: 2
};

var reachStyle = {
  color: 'blue',
  width: 1
};

// Add each FeatureCollection with its own style
Map.addLayer(nodes_merged, nodeStyle, 'Nodes');
Map.addLayer(reaches_merged, reachStyle, 'Reaches');

代码链接

https://code.earthengine.google.com/?scriptPath=users/sat-io/awesome-gee-catalog-examples:hydrology/SWORD-NODES-REACHES-MERGED

单个节点和达到文件已被摄入供参考，用户可通过使用

var ee_nodes = ee.data.listAssets("projects/sat-io/open-datasets/SWORD/nodes");
var ee_reaches = ee.data.listAssets("projects/sat-io/open-datasets/SWORD/reaches");

print('Total of '+ee.List(ee_nodes.assets).size().getInfo()+ ' assets in nodes',ee_nodes.assets);
print('Total of '+ee.List(ee_reaches.assets).size().getInfo()+ ' reaches in nodes',ee_reaches.assets);