IRIS: ICESat-2 River Surface Slope

ICESat-2 River Surface Slope (IRIS) When using this data please cite Scherer D., Schwatke C., Dettmering D., Seitz F. : ICESat-2 Based River Surface Slope and Its Impact on Water Level Time Series From Satellite Altimetry. Water Resources Research, 10.1029/2022WR032842, 2022. 1. Summary The unique multibeam lidar altimeter of ICESat-2 is used to measure reach-scale water surface slope (WSS) every time the spacecraft’s orbit crosses a reach. The method of deriving WSS from simultaneous ICESat-2 ATL13 (Jasinski et al., 2021) observations is described in detail and validated in Scherer et al. (2022). In this ICESat-2 River Surface Slope (IRIS) dataset, we provide the minimum, average, and maximum slope derived with three different approaches (across, along, and combined) per reach. Additionally, we give the standard deviation and epochs of the derived WSS data. The reaches are defined by the SWOT River Database (SWORD, Altenau et al., 2021). Note that Version v0 only includes the reaches studied in Scherer et al. (2022) and uses SWORD Version v1. Following Versions of IRIS have global coverage (limited by ICESat-2 data availability and cloud cover) and use SWORD Version v2. 2. Data Format and Variable Description The IRIS data is stored in a single NetCDF4 file which is structured in a single group containing the following variables: reach_id: The SWORD reach identifier [-] lon: Approx. centroid longitude of the SWORD reach [degrees east] lat: Approx. centroid latitude of the SWORD reach [degrees north] across_flag, along_flag, combined_flag: Flags indicating whether ICESat-2 [across/along/combined] slope is available (1) for the reach or not (0) [-] avg_across_slope, avg_along_slope, avg_combined_slope: Average ICESat-2 [across/along/combined] slope for the reach [mm/km] min_across_slope, min_along_slope, min_combined_slope: Minimum ICESat-2 [across/along/combined] slope for the reach [mm/km] max_across_slope, max_along_slope, max_combined_slope: Maximum ICESat-2 [across/along/combined] slope for the reach [mm/km] std_across_slope, std_along_slope, std_combined_slope: ICESat-2 [across/along/combined] slope standard deviation for the reach [mm/km] n_across_slope, n_along_slope, n_combined_slope: Number of days with ICESat-2 [across/along/combined] slope observations for the reach [-] min_date_across_slope, min_date_along_slope:, min_date_combined_slope: First date of ICESat-2 [across/along/combined] slope observations for the reach [days since 2000-01-01] max_date_across_slope, max_date_along_slope:, max_date_combined_slope: Latest date of ICESat-2 [across/along/combined] slope observations for the reach [days since 2000-01-01] 3. References Scherer D., Schwatke C., Dettmering D., Seitz F. (2022): ICESat-2 Based River Surface Slope and Its Impact on Water Level Time Series From Satellite Altimetry, Water Resources Research, https://doi.org/10.1029/2022WR032842 Jasinski M., Stoll J., Hancock D., Robbins J., Nattala J., Morison J., Jones B., Ondrusek M., Pavelsky T.M., Parrish C. and the ICESat-2-Science-Team (2021). ATLAS/ICESat-2 L3A Inland Water Surface Height, Version 5. [Dataset] Altenau E.H., Pavelsky T.M., Durand, M.T., Yang X., Frasson, R.P.d.M., Bendezu, L. (2021): SWOT River Database (SWORD) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.3898569

ICESat-2 河流表面坡度（ICESat-2 River Surface Slope, IRIS）数据集。使用本数据集时，请引用如下文献：Scherer D., Schwatke C., Dettmering D., Seitz F.：《基于ICESat-2的河流表面坡度及其对卫星测高水位时间序列的影响》，《水资源研究》，10.1029/2022WR032842，2022年。

1. 概述
ICESat-2搭载的独特多波束激光雷达高度计，可在航天器轨道穿过河道河段时，逐河段测量河道尺度的水面坡度（Water Surface Slope, WSS）。从同步ICESat-2 ATL13（Jasinski等，2021）观测数据中推导水面坡度的方法已在Scherer等（2022）中详细阐述并验证。在本ICESat-2河流表面坡度（IRIS）数据集中，我们提供了针对每个河段，通过三种不同方法（横向、纵向及组合方法）推导得到的坡度最小值、平均值与最大值。此外，我们还提供了推导得到的水面坡度数据的标准差与观测历元。河段由SWOT河流数据库（SWOT River Database, SWORD，Altenau等，2021）定义。请注意，v0版本仅包含Scherer等（2022）中研究的河段，且采用SWORD v1版本。后续版本的IRIS数据集将实现全球覆盖（受限于ICESat-2数据可用性与云量影响），并采用SWORD v2版本。

2. 数据格式与变量说明
IRIS数据集存储于单个NetCDF4文件中，该文件包含单个组，组内包含以下变量：
reach_id：SWORD河段标识符 [-]
lon：SWORD河段近似质心经度 [东经度数]
lat：SWORD河段近似质心纬度 [北纬度数]
across_flag, along_flag, combined_flag：标记字段，用于指示该河段是否可获取ICESat-2的[横向/纵向/组合]坡度数据（可获取为1，不可获取为0） [-]
avg_across_slope, avg_along_slope, avg_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度的平均值 [毫米/千米]
min_across_slope, min_along_slope, min_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度的最小值 [毫米/千米]
max_across_slope, max_along_slope, max_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度的最大值 [毫米/千米]
std_across_slope, std_along_slope, std_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度的标准差 [毫米/千米]
n_across_slope, n_along_slope, n_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度观测的有效天数 [-]
min_date_across_slope, min_date_along_slope, min_date_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度观测的首个日期 [距2000-01-01的天数]
max_date_across_slope, max_date_along_slope, max_date_combined_slope：该河段ICESat-2[横向/纵向/组合]坡度观测的最新日期 [距2000-01-01的天数]

3. 参考文献
Scherer D., Schwatke C., Dettmering D., Seitz F. (2022): 《基于ICESat-2的河流表面坡度及其对卫星测高水位时间序列的影响》，《水资源研究》，https://doi.org/10.1029/2022WR032842
Jasinski M., Stoll J., Hancock D., Robbins J., Nattala J., Morison J., Jones B., Ondrusek M., Pavelsky T.M., Parrish C. 以及ICESat-2科学团队 (2021). ATLAS/ICESat-2 L3A内陆水域表面高度，版本5. [数据集]
Altenau E.H., Pavelsky T.M., Durand, M.T., Yang X., Frasson, R.P.d.M., Bendezu, L. (2021): SWOT河流数据库（SWORD）[数据集]. Zenodo. https://doi.org/10.5281/zenodo.3898569

搜集汇总

背景与挑战

背景概述

该数据集利用ICESat-2卫星数据测量河流表面坡度，提供每个河段的坡度统计信息，数据格式为NetCDF4，适用于水文和卫星测高研究。