Category: Oceans

Mapping the Ocean Floor by 2030

Published on by Jonathan Crowe

Newsweek looks at efforts by a group of scientists and mariners to map most of the ocean floor by the year 2030. The objective was endorsed by a meeting of GEBCO, the General Bathymetric Chart of the Oceans, last June. The scale of the project is vast:

To date, more than 85 percent of the seafloor has not been mapped using modern methods. Since 70 percent of the Earth is covered in oceans, this means that we quite literally don’t know our own planet. “We know the surface of Mars better than we do the seafloor,” says Martin Jakobsson, a researcher at Stockholm University.

[Leventhal/MAPS-L]

Marie Tharp: Continental Drift as ‘Girl Talk’

Published on by Jonathan Crowe

tharp-heezenAnother profile of ocean cartographer Marie Tharp, this time from Smithsonian.com’s Erin Blakemore. As Blakemore recounts, Tharp crunched and mapped the sonar sounding data collected by her collaborator, Bruce Heezen; her calculations revealed a huge valley in the middle of a ridge in the North Atlantic seafloor.

“When I showed what I found to Bruce,” she recalled, “he groaned and said ‘It cannot be. It looks too much like continental drift.’ … Bruce initially dismissed my interpretation of the profiles as ‘girl talk’.” It took almost a year for Heezen to believe her, despite a growing amount of evidence and her meticulous checking and re-checking of her work. He only changed his mind when evidence of earthquakes beneath the rift valley she had found was discovered—and when it became clear that the rift extended up and down the entire Atlantic. Today, it is considered Earth’s largest physical feature.

When Heezen—who published the work and took credit for it—announced his findings in 1956, it was no less than a seismic event in geology. But Tharp, like many other women scientists of her day, was shunted to the background.

I really ought to get to Hali Felt’s 2012 biography of Tharp, Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor, at some point. Amazon (Kindle), iBooks.

Previously: Marie Tharp Profile; Soundings: A Biography of Marie Tharp; Marie Tharp and Plate Tectonics; Marie Tharp.

Canada Maps the Arctic Seafloor

Published on by Jonathan Crowe

CBC News reports on the Canadian Coast Guard’s project to map the continental shelf under the Arctic Ocean, now in its third and final year. This is part of Canada’s attempt to stake a claim to the continental shelf (and seas above it) beyond the 200-mile nautical limit, which other Arctic countries (hello, Russia) are also trying to do.

Previously: Arctic Maritime Jurisdiction Map.

Canada’s Arctic Waters Are ‘Dangerously Unmapped’

Published on by Jonathan Crowe

Climate change has made the Arctic increasingly open to shipping, and more ships travel the Canadian Arctic every year. But as Claire Eamer argues in Hakai magazine, the lack of mapping makes such voyages a dangerous proposition. “[J]ust because the ice is melting it doesn’t mean the waterways are safe. The federal Canadian Hydrographic Service (CHS) is responsible for mapping Canada’s waters. So far, they’ve only managed to map roughly 10 percent of Arctic waterways in accordance with international standards.” [CCA]

Monterey Bay Area Seafloor Maps Released

Published on by Jonathan Crowe

New seafloor maps of the Monterey Bay area have been released as part of the California Seafloor Mapping Program. The maps “reveal the diverse and complex range of seafloor habitats along 130 kilometers (80 miles) of the central California coast from the Monterey Peninsula north to Pigeon Point.” [Leventhal Map Center]

Previously: Mapping the California Sea Floor.

Mapping Global Sea Surface Height

Published on by Jonathan Crowe
jason3-20160315
Credit: NASA/JPL Ocean Surface Topography Team.

Jason-3 is the latest earth observation satellite tasked with measuring global sea surface height; its data will be used in weather and climate research (e.g., El Niño, climate change). Launched on January 17, it’s now in its six-month checkout phase and has produced its first complete map, which corresponds well with the map produced by the still-operational Jason-2 satellite, so that’s a good sign. [via]

Seafloor Gravity Map

Published on by Jonathan Crowe
seafloor
NASA Earth Observatory map by Joshua Stevens

The ocean floor is still very much terra incognita: only 5 to 15 percent of it has been mapped via bathymetry. But using military satellite measurements of the Earth’s shape and gravity field, a new map of the ocean floor has been created. “The result of their efforts is a global data set that tells where the ridges and valleys are by showing where the planet’s gravity field varies. […] Shades of orange and red represent areas where seafloor gravity is stronger (in milligals) than the global average, a phenomenon that mostly coincides with the location of underwater ridges, seamounts, and the edges of Earth’s tectonic plates. Shades of blue represent areas of lower gravity, corresponding largely with the deepest troughs in the ocean.”

 

Soundings: A Biography of Marie Tharp

Published on by Jonathan Crowe

Book cover: Soundings A review in Maclean’s brought to my attention a book that came out two months ago: Hali Felt’s Soundings, a biography of Marie Tharp (1920-2006), who with her partner, Bruce Heezen, created the first global map of the ocean floor, discovered the Mid-Atlantic Ridge’s rift valley, and helped provide the evidence for plate tectonics. She’s a major figure in cartography and among women in science, so I thought I should bring this book to your attention, too. Another one to add to the to-read pile.

Previously (on The Map Room): Marie Tharp; Marie Tharp and Plate Tectonics.

Buy at Amazon | author’s page | publisher’s page

Perpetual Ocean

Published on by Jonathan Crowe

Perpetual Ocean - Gulf Stream
You may have seen this already: a beautiful, painting-like visualization of the world’s surface ocean currents between June 2005 and November 2007, which NASA posted last month. The visualization is based on model data from the ECCO2 project. See also this short video on Flickr (Flash required). Image credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.