A new working group on the Regional Assessments of Glacier MAss Change (RAGMAC)

Retreating and thinning glaciers are icons of climate change and impact the local hazard situation, regional runoff as well as global sea level. For past IPCC reports, regional glacier change assessments were challenged by the small number and heterogeneous spatio-temporal distribution of in situ measurement series and uncertain representativeness for the respective mountain range as well as by spatial limitations of current satellite altimetry (only point data) and gravimetry (coarse resolution). Towards IPCC SROCC, there have been considerable improvements with respect to available geodetic datasets. Geodetic volume change assessments for entire mountain ranges have become possible thanks to recently available and comparably accurate DEMs. At the same time, advances have been made in processing methods for radar altimetry (CryoSat-2 swath processing), as well as new spaceborne laser altimetry (ICESat-2) and gravimetry (GRACE-FO) missions are in orbit and about to release data products to the science community. This opens new opportunities for regional evaluations of results from different methods as well as for truly global assessments of glacier mass changes and related contributions to sea-level rise. At the same time, the glacier research and monitoring community is facing new challenges related to data size, formats, and availability as well as new questions with regard to best practises for data processing chains and for related uncertainty assessments.

In this PICO presentation, we introduce a new working group of the International Association of Cryospheric Sciences (IACS) on Regional Assessments of Glacier Mass Change (RAGMAC; https://cryosphericsciences.org/activities/wg-ragmac/). The overall goal of this working group (WG) is bringing together the research community that is assessing regional glacier mass changes from various observation technologies and to come up with a new consensus estimate of global glacier mass changes and related uncertainties. The WG is organized in three work packages, two related to different remote sensing technologies (WG1: glaciological and geodetic DEM-differencing methods, WG2: altimetry and gravimetry) and a third that aims at regional comparisons of corresponding results. Participation is open to everybody who is willing to actively contribute to one or several of these work packages.