Faglige nøgleord: Height systems,Climate change, Earth System Sciences, Geodesy
Oplæg tilgængeligt på: Engelsk, norsk og dansk
DTU Space is world-leading in measuring and modelling the Earth’s gravity field. At DTU Space we conduct measurements of gravity with sensors on land, at sea, and in the air using different instruments. Since 1996 DTU Space has made campaigns across almost all continents supporting development of global models and establishment of national height systems. One among these projects was the computation of a new and updated height system in Nepal leading to the increase of Mount Everest with almost 1 meter.
Have you often been wondering about what the height above sea level for a specific point is, then you should have rather been wondering about: “What is the height above the geoid?” The “Geoid”, you might say. The geoid is the equipotential surface which best fits the undisturbed global sea-level and is used as the reference surface for height systems. In the gravity group at DTU Space we care about computing the geoid forming basis for physical height systems.
Did you know that 99,9995% of the Earth’s gravity field can be considered as known, and hence be accurately modelled mathematically? At DTU Space we conduct research on the remaining 0,0005%. In addition to define height systems with cm-accuracy, measurements of variation in the Earth’s gravity field plays a fundamental role in earth system sciences. Measuring the remaining tiny variations is necessary to compute height systems with cm-level accuracy, but also in order to monitor mass-changes caused by climate change.
Did you know that if heights were only determined using GNSS without accounting for gravity, then water could flow upwards on a map?
These examples and different tasks of a geodesist in the gravity group at DTU Space will be presented in the lecture.