Satellite imagery only goes back so far. To measure the rate of ice loss across the Himalayan glaciers, researchers turned to recently declassified spy satellite photos from 1975. The photos were used to create a digital elevation model (above) which was compared with more recent data. They concluded that the rate of ice loss was accelerating: it was twice as much from 2000 to 2016 than it was from 1975 to 2000. Columbia University, Science News. [Geography Realm]
Climate change means retreating glaciers, which exposes new islands, which means new maps. BBC News reports that five new islands off the northeast coast of Novaya Zemlya, an archipelago in the Russian Arctic that was the site of hundreds of nuclear tests, were mapped by a Russian expedition. The islands were discovered in satellite photos by then-student Marina Migunova, now a naval oceanographic engineer.
Previously: New Map of Greenland and the European Arctic.
This is a map of Antarctic surface ice velocity: the speed at which glaciers flow. It was produced by researchers at the University of California Irvine and the Jet Propulsion Laboratory, using radar interferometry and multiple satellite passes to produce a map 10 times more accurate than previous maps. More: UCI News, Geophysical Research Letters.
The British Antarctic Survey—which despite its name focuses its attention on both polar regions—has released a new one-sheet map of Greenland and the European Arctic. The 1:4,000,000-scale map covers a region from Baffin Island to Novaya Zemlya to Scotland: a region that’s usually on the edges of maps of the Arctic and Europe rather than getting its own map. More importantly, it’s a very recent snapshot of a rapidly changing region: the retreating ice sheet in Greenland is revealing new landscapes. The map costs £12 and is available either folded or rolled from Stanfords and the Scott Polar Research Institute. [BBC]
Nature: “Glaciologists will soon have a treasure trove of data for exploring how Antarctica’s underbelly has changed over nearly half a century. An international team of researchers has scanned and digitized 2 million records from pioneering aeroplane radar expeditions that criss-crossed the frozen continent in the 1960s and 1970s. […] The digitized data extend the record of changes at the bottom of the ice sheet, such as the formation of channels as Antarctica’s ice flows, by more than two decades.” (Modern radar mapping of Antarctica apparently only began in the 1990s.) [WMS]
NASA’s Jet Propulsion Laboratory: “New maps of Greenland’s coastal seafloor and bedrock beneath its massive ice sheet show that two to four times as many coastal glaciers are at risk of accelerated melting as previously thought. Researchers at the University of California at Irvine (UCI), NASA and 30 other institutions have published the most comprehensive, accurate and high-resolution relief maps ever made of Greenland’s bedrock and coastal seafloor. Among the many data sources incorporated into the new maps are data from NASA’s Ocean Melting Greenland (OMG) campaign.”
Using elevation data from stereo satellite observations, David Shean is mapping the retreat of some 1,200 mountain glaciers in the continental United States. “Until recently, glaciers in the United States have been measured in two ways: placing stakes in the snow, as federal scientists have done each year since 1957 at South Cascade Glacier in Washington state; or tracking glacier area using photographs from airplanes and satellites.” Shean’s method, which measures each glacier twice a year and uses automated software to track changes, seems to cover a lot more territory. [GIS and Science]