An Integrated View of Greenland Ice Sheet Mass Changes Based on Models and Satellite Observations

• Published in: Remote Sensing
• Main Authors: Ruth Mottram, Sebastian B. Simonsen, Synne Høyer Svendsen, Valentina R. Barletta, Louise Sandberg Sørensen, Thomas Nagler, Jan Wuite, Andreas Groh, Martin Horwath, Job Rosier, Anne Solgaard, Christine S. Hvidberg, Rene Forsberg
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2019
• Subjects: Climate Change Initiative (CCI); Greenland ice sheet; mass budget; cryosphere; sea level rise; altimetry; mass balance; ice sheet modelling; Science; Q; Greenland; Ice Sheet; Ice Shelves
• Online Access: https://doi.org/10.3390/rs11121407; https://doaj.org/article/aa5a96bb62e04d1bbd34e325e8bbc2f8

The Greenland ice sheet is a major contributor to sea level rise, adding on average 0.47 ± 0.23 mm year <math display="inline"> <semantics> <msup> <mrow></mrow> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </semantics> </math> to global mean sea level between 1991 and 2015. The cryosphere as a whole has contributed around 45% of observed global sea level rise since 1993. Understanding the present-day state of the Greenland ice sheet is therefore vital for understanding the processes controlling the modern-day rates of sea level change and for making projections of sea level rise into the future. Here, we provide an overview of the current state of the mass budget of Greenland based on a diverse range of remote sensing observations to produce the essential climate variables (ECVs) of ice velocity, surface elevation change, grounding line location, calving front location, and gravimetric mass balance as well as numerical modelling that together build a consistent picture of a shrinking ice sheet. We also combine these observations with output from a regional climate model and from an ice sheet model to gain insight into existing biases in ice sheet dynamics and surface mass balance processes. Observations show surface lowering across virtually all regions of the ice sheet and at some locations up to −2.65 m year <math display="inline"> <semantics> <msup> <mrow></mrow> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </semantics> </math> between 1995 and 2017 based on radar altimetry analysis. In addition, calving fronts at 28 study sites, representing a sample of typical glaciers, have retreated all around Greenland since the 1990s and in only two out of 28 study locations have they remained stable. During the same period, two of five floating ice shelves have collapsed while the locations of grounding lines at the remaining three floating ice shelves ...