Impact of GOCE on Regional Geoid Modelling: Finnish Territory

The gravity satellite mission "Gravity field and steady-state Ocean Circulation Explorer" (GOCE, Fig. 1) made its final observations in the fall of 2013. By then it had exceeded its expected lifespan of 20 months with additional 35 months and observed the Earth's gravitational field from a lower orbit as originally planned during the last 6 months of its mission lifetime. Thus, the mission collected more data from the Earth's gravitational field than expected, and more comprehensive global geoid models have been derived ever since. We've combined the latest GOCE global gravity field models with the terrestrial gravity data of Finland and surrounding areas for calculating a new enhanced quasi-geoid model for Finland. Additionally the high resolution global gravity field model EIGEN-6C4 (which includes the full cycle of GOCE data) was used for modelling the higher degrees and orders. Altogether 249 geoid models with different modifications were calculated using the GOCE DIR5 models up to spherical harmonic degree and order 240 and 300 and the EIGEN-6C4 up to degree and order 1000 and 2190.