Data supporting 'Empirical correction of systematic orthorectification error in Sentinel-2 velocity fields for Greenlandic outlet glaciers'

Note: An updated dataset covering the majority of Greenland's marine-terminating glaciers is available as part of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) project through the National Snow and Ice Data Center (NSIDC) at https://doi.org/10.5067/B28FM2QVVYWY. Data supporting the paper: Chudley, T. R., Howat, I. M., Yadav, B. N., & Noh, M. J. (2022). Empirical correction of systematic orthorectification error in Sentinel-2 velocity fields for Greenlandic outlet glaciers. The Cryosphere. 16, 2629–2642, https://doi.org/10.5194/tc-16-2629-2022 Dataset consists of four netCDF files containing stacked Sentinel-2 velocity data of four Greenlandic outlet glaciers (Helheim Glacier, Jakobshavn Isbræ, Store Glacier, and Kangerlussuaq) between 2017 and 2021. Velocity data are derived and corrected following the methods outlined in Chudley et al. (2022). NetCDF files are created by, and tested to be readable by, Python's xarray package. The dimensions of the netCDF file are as follows: X - x coordinates in NSDIC Sea Ice Polar Stereographic North (EPSG:3413). Y - y coordinates in NSDIC Sea Ice Polar Stereographic North (EPSG:3413). time - temporal midpoint of velocity field. The variables of the netCDF file are as follows: dmag - the absolute magnitude of the velocity, in metres per day. dx - the velocity in the x direction, in metres per day. dy - the velocity in the y direction, in metres per day. date1 - the date and time of the first scene acquisition. date2 - the date and time of the second scene acquisition. baseline - the temporal baseline, in days, between scene acquisitions. orbit_pair - the combination of orbital pathways in the string format 'RXXX_RYYY', where XXX is relative orbit number of the first scene and YYY the relative orbit number of the second scene. mag_rmse - the root mean square error of the absolute velocity of the off-ice area. dx_mean - the mean velocity of the off-ice area in the x direction. dx_sd - the standard deviation of the velocity of the off-ice area in the x direction. dy_mean - the mean velocity of the off-ice area in the x direction. dy_sd - the standard deviation of the velocity of the off-ice area in the y direction.

备注：涵盖格陵兰岛绝大多数入海冰川的更新版数据集，可通过美国国家航空航天局（National Aeronautics and Space Administration, NASA）「地球系统数据记录用于研究环境」项目（Making Earth System Data Records for Use in Research Environments, MEaSUREs），由国家冰雪数据中心（National Snow and Ice Data Center, NSIDC）提供，访问链接：https://doi.org/10.5067/B28FM2QVVYWY。
本数据集支撑的论文为：Chudley, T. R.、Howat, I. M.、Yadav, B. N. 与 Noh, M. J.（2022）发表于《冰冻圈（The Cryosphere）》的《Empirical correction of systematic orthorectification error in Sentinel-2 velocity fields for Greenlandic outlet glaciers》，刊载于第16卷，页码2629–2642，访问链接：https://doi.org/10.5194/tc-16-2629-2022。
本数据集包含4个净CDF（netCDF）文件，存储了2017年至2021年间4条格陵兰流出冰川（黑尔海姆冰川（Helheim Glacier）、雅各布港冰川（Jakobshavn Isbræ）、斯托尔冰川（Store Glacier）与康克鲁斯瓦格冰川（Kangerlussuaq））的堆叠式哨兵-2号（Sentinel-2）速度场数据。
本数据集的速度场数据按照Chudley等人（2022）提出的方法进行提取与校正。
净CDF文件由Python的xarray库生成，且经测试可通过该库正常读取。
净CDF文件的维度信息如下：X - 国家冰雪数据中心（NSIDC）海冰北极极面立体投影坐标系（EPSG:3413）下的x坐标；Y - 国家冰雪数据中心（NSIDC）海冰北极极面立体投影坐标系（EPSG:3413）下的y坐标；time - 速度场的时间中点。
净CDF文件包含的变量信息如下：
dmag - 速度绝对幅值，单位为米/天；
dx - x方向速度分量，单位为米/天；
dy - y方向速度分量，单位为米/天；
date1 - 首个影像的获取日期与时间；
date2 - 第二个影像的获取日期与时间；
baseline - 两次影像获取之间的时间基线，单位为天；
orbit_pair - 以'RXXX_RYYY'字符串格式表示的轨道路径组合，其中XXX为首个影像的相对轨道号，YYY为第二个影像的相对轨道号；
mag_rmse - 非冰区域绝对速度的均方根误差；
dx_mean - 非冰区域x方向的平均速度；
dx_sd - 非冰区域x方向速度的标准差；
dy_mean - 非冰区域y方向的平均速度；
dy_sd - 非冰区域y方向速度的标准差。