Tracking Polar Ice Loss: Insights from the GRACE and GRACE-FO Satellites

In the notably warm Arctic summer of 2019, Greenland shed 600 billion tons of ice — sufficient to elevate global sea levels by almost a tenth of an inch (2.2 millimeters) within just two months, according to a recent research.

Conducted by researchers at NASA’s Jet Propulsion Laboratory and the University of California, Irvine, the study also indicates that Antarctica continues to lose mass, especially in the Amundsen Sea Embayment and the Antarctic Peninsula in the western region of the continent; nonetheless, these losses have been somewhat tempered by gains from increased snowfall in the northeast.

“We were aware that the previous summer was notably warm in Greenland, melting every section of the ice sheet,” remarked lead author Isabella Velicogna, senior project scientist at JPL and a professor at UCI. “However, the figures are truly staggering.”

For reference, last summer’s losses are more than twice Greenland’s annual average from 2002 to 2019.

“In Antarctica, the mass loss in the western region is ongoing, which will contribute to an even greater rise in sea level,” Velicogna stated. “Additionally, we observe a mass gain in the Atlantic sector of East Antarctica attributed to an increase in snowfall, which mitigates the substantial mass loss observed in other areas of the continent over the past two decades.”

She along with her colleagues arrived at these findings while establishing data consistency between the recently retired Gravity Recovery and Climate Experiment (GRACE) satellite mission and its successor, GRACE Follow-On.

As collaborative missions between NASA and the German Aerospace Center, as well as NASA and the German Research Centre for Geosciences respectively, the GRACE and GRACE-FO satellites were created to record alterations to Earth’s gravitational force that come from changes in mass, such as water. As water circulates across the globe — moving ocean currents, melting ice, falling rain, etc. — it slightly alters the gravitational pull. Researchers utilize the precise assessments of these fluctuations to track Earth’s water resources, which include polar ice, overall sea levels, and groundwater availability.

The inaugural GRACE mission debuted in 2002 and was decommissioned in October 2017. GRACE-FO, which is based on similar technology and intended to sustain the data record of its predecessor, was launched in May 2018. Due to this short interval, the study team employed independent data to test and confirm that the data from GRACE and GRACE-FO over Greenland and Antarctica were aligned. Velicogna expressed satisfaction with the findings.

“It is wonderful to see how effectively the data align in both Greenland and Antarctica, even on a regional scale,” she stated. “It reflects the immense effort by the project, engineering, and science teams to ensure the mission’s success.”

The study titled “Continuity of Ice Sheet Mass Loss in Greenland and Antarctica From the GRACE and GRACE Follow-On Missions” was published on March 18 in Geophysical Research Letters. Alongside scientists from JPL and UCI, the GRACE and GRACE-FO data continuity project included researchers from the University of Grenoble in France, the University of Utrecht in the Netherlands, and the Polar Ice Center at the University of Washington in Seattle.

JPL oversaw the GRACE mission and currently manages the GRACE-FO mission for NASA’s Earth Science Division in the Science Mission Directorate at NASA Headquarters in Washington. Caltech in Pasadena, California, supervises JPL for NASA.

Further information regarding GRACE and GRACE-FO can be located here:

Jane J. Lee
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307
jane.j.lee@jpl.nasa.gov

Brian Bell
University of California, Irvine
949-824-8249
bpbell@uci.edu

Authored by Brian Bell, UCI, and Esprit Smith, NASA’s Earth Science News Team

2020-052