This Landsat 8 scene was one of the many downloaded on September 16. It shows the area around Juneau, Alaska. Water is dark and includes Lynn Canal, the long water body in the middle of the image. Green is vegetation and forested mountain areas.
This image also provides a clear view of the Juneau Icefield. Several glaciers flow from this icefield, and glaciologists are using the 42-year Landsat archive to monitor the advance and retreat of the glaciers over time. Since Landsat 7 and Landsat 8 together provide an 8-day repeat cycle, Landsat can be an important supplement to ground-based glacier monitoring.
Scientists, students, city planners, environmental engineers, and many others have been able to use the vast archive of Landsat data free of charge to support and enhance their research. The free availability of Landsat data enables scientists to conduct large-scale global studies that would otherwise be too costly.
Safeguarding freshwater resources is crucial, and while scientists use a variety of ground-based techniques to gauge water quality, the Landsat program has provided water quality data from orbit for decades.