Global Land Ice Velocity Extraction from Landsat 8 (GoLIVE), Version 1

This data set is a compilation of ice velocity mappings generated from pairs of Landsat 8 panchromatic images acquired from May 2013 to present covering all terrestrial permanent ice within the latitude range 82°S to 82°N that is larger than 5 km2 in area. The data are updated monthly with new images acquired by Landsat 8 that are then paired with older images acquired within 400 days of the new acquisition for the Antarctic ice sheet, 112 days for the Greenland ice sheet, and 96 days for all other glacierized areas. The data are generated by an image correlation algorithm that produces grids of ice displacement referenced to in-image rock outcrops, slow moving ice, or if lacking that, using the satellite's geo-positioning (accurate to +/- 5 m). Velocity vector grids are generated at a sample spacing of 300 m from small sub-images that are either 300 m or 600 m on a side, depending on the region. For example, ice sheet areas are mapped with 600 m x 600 m sub-images, and mountain glaciers are mapped with 300 m x 300 m sub-images. Accuracy of the velocity data varies depending on the time separation between the images, ranging between ~1 m/d per day to 0.02 m/d per day.

本数据集为2013年5月至今获取的陆地卫星8号（Landsat 8）全色影像（panchromatic images）对生成的冰速制图（ice velocity mappings）合集，覆盖南纬82°至北纬82°范围内面积大于5平方千米的所有陆地永久冰体。该数据集每月更新一次，更新时采用新获取的Landsat 8影像，针对南极冰盖、格陵兰冰盖及其他冰川覆盖区，分别选取新影像获取前400天、112天及96天内的旧影像与新影像配对。本数据集通过图像相关算法（image correlation algorithm）生成冰位移网格，以影像内的岩石露头（rock outcrops）、慢速移动冰体作为参考基准；若缺乏上述参考物，则采用卫星地理定位数据（精度为±5米）。速度矢量网格（velocity vector grids）的采样间距为300米，其生成所用的子图像（sub-images）边长根据区域差异分为300米或600米：例如冰盖区域采用600米×600米的子图像，山地冰川则采用300米×300米的子图像。冰速数据的精度随影像拍摄间隔时长变化，精度范围约为1米/天至0.02米/天。