13 december 2024
New Rock Glacier Velocity (RGV) Working Group kicks off!
Developing a method-specific best practice documents associated with Rock Glacier Inventories and Kinematics
In 2022, Rock Glacier Velocity (RGV) was added as a new quantity of the ECV Permafrost (WMO, 2022). RGV documents permafrost changes in mountains, in complement to Permafrost Temperature (PT) and Active Layer Thickness (ALT) observations. RGV is a time series of annualised surface velocity values expressed in m/y and measured/computed on a rock glacier unit or a part of it, following the definition of the Rock Glacier Inventories and Kinematics (RGIK) IPA Standing Committee (RGIK, 2023a; 2023b).
Key documents relating to rock glacier kinematics generated vis the Permafrost_cci project are available.
In 2024, partners from the Permafrost_cci and the SwissUniversities Orodapt projects kicked off a RGV inter-comparison working group aiming to
- simultaneously generate RGV on similar landforms
- inter-compare results using various methods and
- identify concrete issues occurring during the production.
The final objectives are to agree on common workflows and compile best practice documents to enable the systematic production of RGV, as well as promote the development of long-term monitoring strategies and further the use of RGV as climate change indicator. The working group participants were divided into three methodological subgroups (in-situ differential GNSS, optical remote sensing based on images from manned or unmanned aircrafts and Interferometric Synthetic Aperture Radar using Sentinel-1 images). All participants worked independently to produce RGV following similar instructions and using the same datasets on three rock glaciers in the French, Italian and Swiss Alps.
In November 2024, a workshop was held in Fribourg (Switzerland) gathering 19 participants (16 on-site) who performed the intercomparison exercise. Fruitful discussions both within three subgroups as well as in plenary contributed to agreeing on principles for standardised workflows for RGV production and planning the future steps. The working group will continue its activities in the coming years with the objective to release method-specific best practice documents associated to the generic RGIK guidelines.
References
RGIK (2023a) Rock Glacier Velocity as an associated parameter of ECV Permafrost: Baseline concepts (Version 3.2). Rock glacier inventories and Kinematics, 12 pp. RGV_BCv3.2. https://www.rgik.org.
RGIK (2023b) Rock Glacier Velocity as associated product of ECV Permafrost: practical concepts (version 1.2). Rock glacier Inventories and Kinematics, 17 pp. RGV_PCv1.2. https://www.rgik.org.
WMO (2022) The 2022 GCOS ECVs Requirements. GCOS – 245. World Meteorological Organization https://library.wmo.int/idurl/4/58111.