Geodesy is the science of measuring the Earth’s surface geometry, including ice and ocean surfaces, and of determining Earth’s gravity field. Measured changes of geometry and gravity in time inform us about Earth system processes such as those associated to climate change.
Geodetic measurements, primarily by satellites, allow us to monitor changes of the Greenland Ice Sheet and the Antarctic Ice Sheet. In combination with physical modeling, these measurements allow us to improve our understanding of how processes of ice sheet change, of sea-level change, and of the solid Earth are linked. For example, the solid Earth surface rises or subsides in reaction to past and present changes of the ice and water loads resting on it. Measuring present-day bedrock displacement therefore allows inferences on ice sheet changes over the past millennia.
Apart from using data from various satellite missions, we conduct our own ground-based and airplane-based measurements during frequent expeditions to the polar regions. The data analysis and interpretation typically combine several types of geodetic measurements with results from numerical modeling in neighboring disciplines like geophysics, glaciology, and climate science.
Research questions
- How can opportunities of new measurement techniques and analysis techniques be exploited to better determine processes of ice sheet change?
- How can numerical modeling (e.g. climate modeling, ice sheet modeling) best benefit from geodetic measurements? Conversely, how can the analysis and interpretation of geodetic measurements best benefit from numerical modeling?
- How can bedrock displacement, including at places where bedrock is hidden under ice or ocean, be determined from measurements? What can measured bedrock displacements tell us about glacial history and solid Earth properties?
Methods
- Measurements of Global Navigation Satellite Systems (GNSS) signals for the determination of coordinate changes of marked bedrock sites with accuracies on the millimeter level
- GNSS measurements on ice surfaces for the calibration and validation of satellite data
- Analysis of satellite altimetry data over ice sheets
- Analysis of results from satellite gravimetry, such as from the GRACE and GRACE-Follow-On missions
- Analysis of data from optical and radar remote sensing satellites for the determination of glacier flow velocities, surface deformations and glacier frontlines
- Combination of complementary geodetic techniques and results from numerical modeling for the separation of different processes of the ice sheets, the solid Earth, and the oceans
Responsible persons
Prof. Martin Horwath, Institut für Planetare Geodäsie, Technische Universität Dresden
Dr. Mirko Scheinert, Institut für Planetare Geodäsie, Technische Universität Dresden
Projects we participate in
BMBF GROCE – Greenland Ice Sheet Ocean Interaction
TP6 – Glacial isostasy, mass balance and ice dynamics
DFG SPP Sealevel (SPP1889) – Regional Sea Level Change and Society
Reconciling ocean mass change and GIA from satellite gravity and altimetry (OMCG)