Geodesy is the science of determining the shape of the Earth and its gravity field and provides the basis for many applications in mapping, engineering, navigation and monitoring of the Earth system. Integral to these activities, geodetic reference frames basically consist of a list of coordinates of selected reference stations to which all subsequent measurements can be referred to, ensuring consistency over long distances and time periods. It allows, e.g., continuous monitoring of sea-level rise or quantifying mass transport in the Earth’s hydrological cycle, including melting of polar ice sheets and glaciers.
Of specific interest for studying sea- level rise and mass distributions are the reference frames for height and gravity. For more than 10 years, NMBU and BAdW cooperate on theory of regional geoid modelling. In the initial phase (2010-2011), the cooperation was supported by DAAD-PPP. The current proposal aims at strengthening the existing cooperation taking advantage of newly funded PhD and postdoctoral positions at NMBU. Additional networking activities will strengthen existing connections to the Norwegian Water Resources and Energy Directorate (NVE) on questions of hydrological modelling and glacier monitoring.
When realizing reference frames, temporal variations caused by mass transport in the earth system, e.g., caused by continental hydrology or glacial isostatic adjustment must be accounted for.
NMBU’s current PhD student (Mr. Bramanto) is working on time-variable effects in time series of terrestrial absolute gravimetry, with focus on contributions from continental hydrology. The cooperation with BAdW will allow an extension from terrestrial to areal observations by means of satellite gravimetry. The new postdoctoral and PhD projects are related to realization of a seamless height reference frame for land and ocean areas, thus exploiting NMBU’s expertise in satellite altimetry and BAdW’s expertise in combined regional geoid modelling.