SUPERSEDED: Pacific Walrus Coastal Haulout Occurrences Interpreted from Satellite Imagery, 2023

This data release contains maps, geospatial files, and a table of the satellite imagery types with the dates when they were collected and examined to interpret the presence of, and area occupied by, walruses at terrestrial haulouts. Estimates of the land area occupied by walruses are provided based on interpretation by experienced image reviewers. The images are from a variety of Earth observing satellite imagery sources collected over coastal areas of the Chukchi Sea (northwestern Alaska and northeastern Russia) in autumn when walruses come ashore in large numbers to rest in the absence of sea ice. Earth observing imagery sources used in this data release include (but are not limited to) optical imagery collections by: (1) the European Space Agency's Sentinel-2 mission and (2) the Plant Labs Planet Scope constellation, as well as synthetic aperture radar imagery collected by: (1) European Space Agency's Sentinel-1 mission; (2) the DLR (German Aerospace Agency) TerraSAR-X satellite (X-band), and (3) the Umbra Space satellite constellation (X-band).

本数据集包含地图、地理空间文件，以及一张卫星影像类型对照表，表中记录了各影像的采集与解译日期，用于解译楚科奇海沿岸海象陆上聚集点的海象存在情况与占据区域。本数据集提供了由资深影像解译人员通过目视解译得出的海象占据陆地面积估算值。

所用影像源自多种地球观测卫星数据源，采集于楚科奇海（阿拉斯加西北部与俄罗斯东北部）沿岸区域的秋季时段——此时海冰消融，海象会大规模登陆休憩。

本数据集所使用的地球观测影像数据源包括但不限于以下光学影像采集成果：(1) 欧洲空间局（European Space Agency）的Sentinel-2任务；(2) Plant Labs的Planet Scope卫星星座；此外还包含以下合成孔径雷达（Synthetic Aperture Radar，SAR）影像：(1) 欧洲空间局的Sentinel-1任务；(2) 德国航空航天中心（DLR）的TerraSAR-X卫星（X波段）；(3) Umbra Space卫星星座（X波段）。