• → European Space Agency

      • Space for Europe
      • Space News
      • Space in Images
      • Space in Videos
    • About Us

      • Welcome to ESA
      • DG’s blog
      • For Member State Delegations
      • Business with ESA
      • Law at ESA
      • ESA Exhibitions
      • ESA Publications
      • Careers at ESA
      • ESAshop
    • Our Activities

      • Space News
      • Observing the Earth
      • Human and Robotic Exploration
      • Space Transportation
      • Navigation
      • Space Science
      • Space Engineering & Technology
      • Operations
      • Telecommunications & Integrated Applications
      • Preparing for the Future
    • Careers at ESA

    • For Media

      • Media
      • ESA TV
      • Videos for professionals
      • Photos
    • For Educators

    • For Kids

    • ESA

    • Observing the Earth

    • CryoSat

    • ESA's ice mission
    • Introducing CryoSat
    • Science in focus
    • Sea ice
    • Ice sheets
    • Surpassing expectations
    • About the mission
    • Facts and figures
    • Satellite
    • Instruments
    • About the launch
    • Operations and data
    • Data flow
    • Data products
    • Essential groundwork
    • Multimedia
    • Image gallery
    • Video gallery
    • Downloads
    • Documents & publications

    ESA > Our Activities > Observing the Earth > CryoSat

    CryoSat unveils secrets of the deep

    Gravity reveals seafloor
    3 October 2014

    ESA’s ice mission has been used to create a new gravity map, exposing thousands of previously unchartered ‘seamounts’, ridges and deep ocean structures. This vivid new picture of the least-explored part of the ocean offers fresh clues about how continents form and breakup.

    Carrying a radar altimeter, CryoSat’s main role is to provide detailed measurements of the height of the world’s ice. This allows us to see how the thickness of the ice changes, seasonally and in response to climate change.

    However, CryoSat works continuously, whether there is ice below or not. This means that the satellite can also measure the height of the surface of the sea. These measurements can be used to create global marine gravity models and, from them, maps of the seafloor.

    CryoSat

    Although invisible to the eye, the sea surface has ridges and valleys that echo the topography of the ocean floor, but on a greatly reduced scale.

    The effect of the slight increase in gravity caused by the mass of rock in an undersea mountain is to attract a mound of water several metres high over the seamount. Deep ocean trenches have the reverse effect.

    These features can only be detected by using radar altimetry from space.

    Scientists from Scripps Institute of Oceanography at University California San Diego in the US and colleagues tapped into two new streams of satellite data to create a new gravity map mirroring features of the ocean floor – twice as accurate as the previous version produced nearly 20 years ago.

    Atlantic bed imprinted in gravity

    They used measurements that CryoSat has captured over the oceans during the last four years as well as measurements from the French–US Jason-1 satellite, which was retasked to map the gravity field during the last year of its 12-year mission.

    Combined with existing data, the new map, described in the journal Science, reveals details of thousands of undersea mountains rising a kilometre or more from the bottom of the ocean.

    The new map offers geophysics new tools to investigate little-studied remote ocean basins and processes such as seafloor spreading.

    “The kinds of things you can see very clearly now are abyssal hills, which are the most common land form on the planet,” said David Sandwell, lead scientist of the paper and a geophysics professor at Scripps.

    The authors of the study say the map provides a new window into the tectonics of the deep oceans.

    Previously unseen features in the map include newly exposed continental connections across South America and Africa, and new evidence for seafloor spreading ridges at the Gulf of Mexico that were active 150 million years ago and are now buried by layers of sediment more than a kilometre thick.

    Indian Ocean bed imprinted in gravity

    One of the most important uses of this new marine gravity field will be to improve the estimates of seafloor depth in the 80% of the oceans that remains uncharted or is buried beneath thick sediment.

    The new map will also provide the foundation for the upcoming new version of Google’s ocean maps to fill large voids between shipboard depth profiles.

    ESA’s Richard Francis, co-author and project manager for the development of CryoSat, said, “Although CryoSat’s primary mission is in the cryosphere, we knew as soon as we selected its orbit that it would be invaluable for marine geodesy, and this work proves the point.”

    Rate this

    Views

    Share

    • Currently 5 out of 5 Stars.
    • 1
    • 2
    • 3
    • 4
    • 5
    Rating: 4.9/5 (101 votes cast)

    Thank you for rating!

    You have already rated this page, you can only rate it once!

    Your rating has been changed, thanks for rating!

    11226
    Tweet

    Related articles

    Ice sheet highs, lows and loss20 August 2014

    Ice sheet highs, lows and loss20 August 2014 Measurements from ESA’s CryoSat mission have been used to map the height of the huge ice sheets that blanket Greenland and Antarctica and show how they are changing. New results reveal combined ice volume loss at an unprecedented rate of 500 cubic kil...

    Special delivery from CryoSat11 June 2014

    Special delivery from CryoSat11 June 2014 New data products from ESA’s ice mission open new doors for scientists studying oceans.

    CryoSat hits land21 December 2012

    CryoSat hits land21 December 2012 ESA’s ice mission is now giving scientists a closer look at oceans, coastal areas, inland water bodies and even land, reaching above and beyond its original objectives.

    • Access CryoSat data
    • Related links
    • Science: New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure
    • Scripps Institution of Oceanography
    • Jason-1
    • App Store
    • Subscribe
    • mobile version
    • ESA Observing the Earth Twitter

    @ESA_EO

    • FAQ

    • Site Map

    • Contacts

    • Terms and conditions