ENAC Seminar Series by Dr. Poul Christoffersen
Event details
| Date | 22.11.2018 |
| Hour | 09:00 › 10:00 |
| Speaker | Dr. Poul Christoffersen |
| Location | |
| Category | Conferences - Seminars |
9:00 – 10:00 – Dr. Poul Christoffersen
Reader in Glaciology, Scott Polar Research Institute, University of Cambridge
Glaciers in the 21st century: fast decline or complex response?
With global temperatures rising by 0.2 °C per decade, glacial ice is increasingly lost in both alpine and polar environments. At present, 665 km3 of glacial ice is lost annually, exposing more than a billion people to increased flood risk. While the contemporary decline of glacial ice masses is relatively well understood through satellite-derived measurements, there is a paucity of observations, especially from the base of glaciers, which makes the theoretical approximation of their flow uncertain. Predictions of future changes in glacial ice masses are consequently ambiguous.
In this talk, I will present outcomes from the ERC-funded RESPONDER research programme, which addresses this knowledge gap with a series of unique scientific experiments on Store Glacier in West Greenland. We have discovered that UAV photogrammetry can identify basal hydrology through uplift and velocity changes at the glacier’s surface, and that stationary radar systems can capture ice deformation rates from to the daily displacements of internal layers in the glacier. We have established daily records of basal melt rates, which have never previously been measured on glaciers, and these rates were far higher than what energy balance calculations predict. Complementary to these experi-ments are time series of data generated by installing sensors in boreholes drilled to the base of the glacier, confirming that warm basal conditions prevail beneath very cold ice, and pointing to a source of energy so far unaccounted for.
The data collected at Store Glacier are revealing processes not included in the current genera-tion of numerical ice sheet models, and we are using this information to establish improved physical-ly-based formulations of glacial processes, thereby making numerical simulations of glacial ice masses more realistic. The latter is essential for accurate prediction of future rates of global sea level rise in a warming world.
Reader in Glaciology, Scott Polar Research Institute, University of Cambridge
Glaciers in the 21st century: fast decline or complex response?
With global temperatures rising by 0.2 °C per decade, glacial ice is increasingly lost in both alpine and polar environments. At present, 665 km3 of glacial ice is lost annually, exposing more than a billion people to increased flood risk. While the contemporary decline of glacial ice masses is relatively well understood through satellite-derived measurements, there is a paucity of observations, especially from the base of glaciers, which makes the theoretical approximation of their flow uncertain. Predictions of future changes in glacial ice masses are consequently ambiguous.
In this talk, I will present outcomes from the ERC-funded RESPONDER research programme, which addresses this knowledge gap with a series of unique scientific experiments on Store Glacier in West Greenland. We have discovered that UAV photogrammetry can identify basal hydrology through uplift and velocity changes at the glacier’s surface, and that stationary radar systems can capture ice deformation rates from to the daily displacements of internal layers in the glacier. We have established daily records of basal melt rates, which have never previously been measured on glaciers, and these rates were far higher than what energy balance calculations predict. Complementary to these experi-ments are time series of data generated by installing sensors in boreholes drilled to the base of the glacier, confirming that warm basal conditions prevail beneath very cold ice, and pointing to a source of energy so far unaccounted for.
The data collected at Store Glacier are revealing processes not included in the current genera-tion of numerical ice sheet models, and we are using this information to establish improved physical-ly-based formulations of glacial processes, thereby making numerical simulations of glacial ice masses more realistic. The latter is essential for accurate prediction of future rates of global sea level rise in a warming world.
Practical information
- General public
- Free
Organizer
- ENAC
Contact
- Cristina Perez