Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Most changes in Earth’s shape are due to changes in climate

10.01.2005


Scientists using NASA satellite data found the shape of the Earth appears to be influenced by big climate events that cause changes in the mass of water stored in oceans, continents and atmosphere.

The study’s principal researchers are Minkang Cheng and Byron D. Tapley, of the Center for Space Research, University of Texas at Austin. They reviewed climate events like El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) that affect the amount of water moving in the oceans, atmosphere and continents.

The study shows significant variations in the shape of the Earth, defined by the Earth’s gravity field, or geoid, during the past 28 years might be partially linked to climate events. The study examined Earth’s oblateness, how much its rounded shape flattens at the poles and widens at the equator. Scientists measured the distance from ground stations to satellites by using Satellite Laser Ranging (SLR) data that are accurate within one millimeter.



The data reflected mass changes as water redistributed in oceans, atmosphere, and in soil. The redistribution resulted in slight changes of the Earth’s gravity field, detectable with geodetic satellites, those that study of the size and shape of the Earth.

The researchers found over the past 28 years, two large variations in the Earth’s oblateness were connected to strong ENSO events. Variations in mass distribution, which caused the change in the gravity field, were predominantly over the continents, with a smaller contribution due to changes over the ocean. The cause of a variation in the Earth’s mass over the 21-year period between 1978 and 2001, however, still remains a mystery.

The scientists also found that another change in mass distribution may have started in late 2002, which coincides with the moderate El Niño that developed at that time. "The main idea, however, is that the Earth’s large scale transport of mass is related to the long-term global climate changes," said Cheng. Cheng and Tapley’s research relied on NASA’s SLR data to measure changes in the longest wavelengths of the Earth’s gravity field in order to see how the global-scale mass was redistributed around the world.

The Earth’s gravity is an invisible force of attraction that pulls masses together. The relative motion of a small lighter object, such as a spacecraft, to a large heavy object such as the Earth, depends on how much mass each object has and how that mass is distributed. Scientists can measure the changes in Earth’s gravitational pull using instruments on the ground to track satellites in space. So, water mass shifts on Earth and the changes in shape of the Earth can be detected.

The long-term history of the SLR measurements make it possible for scientists to see the changes over time in melting glaciers and polar ice sheets and the associated sea level change. The SLR data have also been used to detect the motion of global tectonic plates on which landmasses rest, the deformation of the Earth’s crusts near plate boundaries, and the orientation and rate of spin of the Earth.

In March 2002, NASA and the German Aerospace Center launched the Gravity Recovery and Climate Experiment (GRACE) to sense small-scale variations in Earth’s gravitational pull from local changes in Earth’s mass. GRACE data will assist with future studies similar to Cheng and Tapley’s research. The GRACE satellite, together with 18 other NASA research satellites, have opened new windows to exploring Earth and to understanding the intricate processes that support life.

The study was published in a recent issue of the Journal of Geophysical Research-Solid Earth.

Rob Gutro | EurekAlert!
Further information:
http://www.gsfc.nasa.gov

More articles from Earth Sciences:

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

nachricht Drones survey African wildlife
11.07.2018 | Schweizerischer Nationalfonds SNF

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>