Nadir photographs taken during low-altitude transects of the Arctic Network of national park units and Selawik National Wildlife Refuge, Alaska, July 2013

Nadir images taken by automatic time-lapse from a Drift HD-170 (focal length 5.00 mm) and a GoPro Hero3 Black Edition (focal length 2.77 mm) of the arctic landscape during low altitude transects at five second intervals. Transects were conducted from small aircraft over the National Park Service’s Arctic Network (Bering Land Bridge National Preserve, Cape Krusenstern National Monument, Gates of the Arctic National Park and Preserve, Kobuk Valley National Park, and Noatak National Preserve) and the U.S. Fish and Wildlife Service’s Selawik National Wildlife Refuge in northwest Alaska.本数据集收录了由Drift HD-170（焦距5.00 mm）与GoPro Hero3 Black Edition（焦距2.77 mm）两款运动相机，以5秒为间隔的自动延时摄影模式，在低空勘察航线中拍摄的北极地貌天底影像（nadir images）。本次勘察航线由小型航空器执行，飞行范围覆盖美国国家公园管理局（National Park Service）北极网络下辖的白令陆桥国家保留地（Bering Land Bridge National Preserve）、克森斯滕角国家纪念地（Cape Krusenstern National Monument）、北极之门国家公园及保留地（Gates of the Arctic National Park and Preserve）、科伯克谷国家公园（Kobuk Valley National Park）与诺阿塔克国家保留地（Noatak National Preserve），以及美国鱼类及野生动物管理局（U.S. Fish and Wildlife Service）所辖的阿拉斯加西北部瑟拉威克国家野生动物保护区（Selawik National Wildlife Refuge）。