Envisaging a new era of gravity field research

Abstract

The investigation of the Earth’s gravity field will enter a new era at the turn of the forthcoming millenium. Despite the fact that a remarkable improvement of our knowledge of the gravity field has been achieved during the past decades the coming years promise another giant step in better understanding the system earth. The surprising success of the Global Positioning System, the breathtaking development of microcomputer technology but also the availability of highly sophisticated sensor components for reasonable prices enable to envisage some promising space borne concepts of gravity field missions. Various gravity sensors with complementary sensitivity characteristics will have the potential of measuring the various spectral parts of the static gravity field with high precision. The snapshots of the gravity field in monthly intervals should allow to detect time dependencies of the gravity field in certain parts of the spectrum.

In a first part the need of an improved gravity field is pointed out and a short overview of the scientific arguments is given. It is shown that the expected results will provide insight into the behavior of important features of the system earth. The improvement of accuracy and resolution can be achieved only by new space-borne gravity measurement techniques. The basic principles are sketched and the development of various mission concepts of three decades are reviewed. All three basic concepts discussed extensively during that time, high-low SST, low-low SST and SGG have a good chance to become realized within the coming years. CHAMP and GRACE will be launched at the turn of the millenium. GOCE will (hopefully) follow some years later. One should be aware of the fact that the coming years will represent an enormous challenge for the geo-sciences, not only with respect to the measurement and processing procedures, but also with respect to the interpretation and inversion of the data.