Highlights

Recently NASA study says that the Earth Mass has deviated in August 2020 as compared to that of 2004-09 and the sea level increase may be due to the change in earth mass.

NASA Study

NASA study says that the change in earth mass is mainly caused due to land movement relative to sea, changes in land movement was more in snow and ice-covered area. This is because, here the ice cover is disappearing. Especially, here the surface mass of the earth is being lost.

NASA formally released maps showing how several factors affect the sea level increase.

Land Motion

  • The natural drivers such as shifting of tectonic plates, compression of buried ocean sediments produce gradual motion.
  • The human driven factors such as ground water extraction, oil production and drying of peat soils also cause land motion.
  • NASA’s GNSS (Global Navigation Satellite System) helped analyse land movement.
  • NASA Says oil production and ground water extraction can produce subsidence at the rate of centimeter in a single year as compared to mm per year as caused by natural processes.

Ocean Altimetry missions

The missions are used to study about ocean topography. The Radar Altimeter send out pulses of radio waves that bounce the surface of ocean and reflect back towards the satellite. The satellite calculates the time taken for the signal to return. Using this, the scientists can determine the height of the sea.

Reasons for change in earth masses

The changes were mainly because changes in amount of ice, water and snow. These changes were calculated by GRACE Mission. GRACE are Known as Gravity Recovery and Climate Experiment. The jointly mission was launched by NASA and German Aerospace Center. The Joint mission found that there were mass losses of Greenland ice sheet between 2002 and 2016. Also, the GRACE mission found that between 2002 and 2017, there were mass losses of 1.2 mm in a single year.

Greenland

It is a world’s largest island and it losses ice masses. The ice masses are more than that of Antarctica. Greenland lost around 200 Gigatonnes of ice in a single year from its coastal glaciers alone.

GRACE Mission

GRACE means Gravity Recovery and Climate Experiment. The mission was a jointly developed by German space agency (German Aerospace Center) and NASA. The Twin satellites took detailed measurements of Earth’s gravity field anomalies. GRACE Mission was launched in March 2002 and to the end of its science mission in October 2017. Earth Surface Mass has deviated Earth Surface Mass has deviated