The NASA/Goddard Space Flight Center video tape, "Glacier Bay, Alaska, from the Ground, Air and Space," is an assemblage of live-captured and remotely-sensed computer images of glaciers at Glacier Bay, Alaska. Dr. James P. Strong/ Scientific Visualization Studio (SVS) at GSFC's Earth and Space Data Computing Division and Cindy Starr/HSTX/SVS produced this narrated video under the direction and guidance of Dr. Dorothy K. Hall/Code 974, Laboratory for Hydrospheric Processes at GSFC's Hydrological Sciences Branch.
Hand-drawn maps
Dr. Hall, along with other scientists, has studied the movement of some of the glaciers in Glacier Bay, Alaska, as well as glaciers in other parts of the world. For her studies of Glacier Bay, Dr. Hall obtained material from colleagues and historical collections including explorers' hand-drawn maps of these glaciers from as far back as 1794.
Satellite image of Glacier Bay, Alaska
Dr. Hall has also studied satellite imagery from NASA's Landsat series of satellites, which has acquired images since 1972. Landsat enables study of the movement of glaciers from the MultiSpectral Scanner, with a spatial resolution of 79 m, and the more advanced Thematic Mapper, with a spatial resolution of 28.5 m.
Recent and historical slides
and photographs.
(119K) An animated glacier diagram.
The video's producers used their combined visualization and scientific expertise to weave the historical records, including photographs from the early part of this century, more recent slides, and graphic images, with live action video segments and computer animation of satellite imagery. The result is a video that provides a lively historical perspective of glacier changes in the region.
Scientists use special computer techniques to study glaciers. Here, a satellite image is registered to a map drawn by early explorers.
Pushing forward scientific analysis of these glaciers, the Laboratory for Hydrospheric Processes used special computer techniques to combine historical records of Glacier Bay with satellite data "... providing a wealth of information about the deglaciation at Glacier Bay" according to Dr. Hall. Scientists are able to measure changes in glacier terminus position for periods over the past two centuries by registering satellite images to maps drawn by early explorers.
The video shows how scientists can relate the movement of glaciers to regional climate change, where applicable. Because tidewater glaciers (click to see Java Applet) follow their own cycles of advance and retreat, their movement cannot be directly tied to short-term climate. Thus the tidewater glaciers in Glacier Bay are not good indicators of short-term regional climate change. However, the non-tidewater glaciers (click to see Java Applet) of Glacier Bay, which have shown some evidence of retreat over the last 40 years or so, most likely can be tied to regional climate change. Non-tidewater retreat is probably a result of amelioration of regional climate as evidenced by a tendency toward increasing air temperatures measured at nearby meteorological stations.
(1MB) Quicktime animation showing computer techniques used to create glacier
fly-bys.
Starr produced a host of special effects for the video using images created by Janet Chien/GSFC/Laboratory for Hydrospheric Processes. Starr created nine spectacular "fly-bys" of scenic rides over the glaciers using the SVS's Advanced Visualizer from Wavefront Inc.
(952K) Quicktime animation of live video footage of ice calving from the
Johns Hopkins Glacier.
In addition, the video contains dramatic, live footage of ice fronts calving into the sea, as well as other video footage shot on location by David Affens/Code 480.
For more information contact Judy Laue, laue@gsfc.nasa.gov.