Amery Ice Shelf Grounding Zone defined as interpreted slope break in MODIS images

Grounding Zone of the Amery Ice Shelf, East Antarctica defined by break of surface slope as determined through interpretation of MODIS images. It defines the landward edge of the grounding zone and therefore the maximum extent of the ice shelf.The MODIS data from the 250 m Channel 2 were processed to a reflectance product and remapped to a Polar Stereographic Projection. The image contrast was stretched so that subtle variations in reflectance could be perceived. The variation in reflectance was used as an indicator of variation in slope. The break of slope of the snow surface was picked interactively on an image display at a frequency sufficient to define the shape of the grounding zone margin. The series of points are provided as a Point shapefile file as well as a set of arcs connecting the points. The point positions are given in geographic coordinates.This work was completed as part of ASAC projects 2224 and 3067 (ASAC_2224, ASAC_3067).

本数据集为南极东部埃默里冰架（Amery Ice Shelf）的接地带（Grounding Zone），通过解译中分辨率成像光谱仪（MODIS）影像确定的地表坡度转折处完成划定。该边界为接地带的陆侧边界，同时也是冰架的最大分布范围。本数据集所用的MODIS 250米2波段数据经处理生成反射率产品，并重投影至极方位投影（Polar Stereographic Projection）。通过拉伸影像对比度以凸显反射率的细微变化，将反射率变化作为地表坡度变化的指示因子。研究人员通过交互式影像显示界面手动拾取雪面坡度转折处，采样频率足以准确刻画接地带边缘的形态。数据集以点形状文件（Point shapefile）形式提供一系列点位，同时附带连接这些点位的弧段数据；所有点位均采用地理坐标给出。本研究作为ASAC项目2224与3067（ASAC_2224、ASAC_3067）的一部分完成。