Search Results (2)

The quantum technology absolute gravimeters, gradiometers, and clocks are at the forefront of the instrumentation to be exploited in a future gravity mission (the QSG mission concept). Apart from the quantum payload, the mission design defines the choice of the number of satellites and the satellite orbit constellation, with the goal of optimizing the observation of the earth’s gravity field and reducing aliasing phenomena. Our goal is to define the realistic gravity field changes generated by glaciers and lakes and define the sensitivity of the quantum gravity mission for the detection of hydrologic and cryospheric mass changes. The analysis focuses on mass changes in the high mountains of Asia and the South American continent. The mass changes are based on terrestrial and satellite observations and are of a climatic origin. We show that compared to the existing GRACE-FO mission, a quantum gravity mission significantly improves the detection of the climatic mass gain of lakes and mass loss of glaciers, allowing for smaller mass features to be distinguished, and smaller mass losses to be detected. The greater signal is the seasonal signal with a yearly period, which would be detected at the 10 Gt level for areas > 8000 km². The yearly mass loss of the Patagonian glaciers can be detected at the 5 Gt/yr level, an improvement from the 10 Gt/yr detectable by GRACE-FO. Spatial resolution would also be improved, with an increase of about 50% in spatial frequency for the detection of the mass change rate of lakes and glaciers in Tibet. The improved spatial resolution enables an improved localization of the lakes and glaciers affected by climatic mass change. The results will contribute to defining the user requirements of the future QSG missions. Full article

Atom-interferometry gravity gradiometry has been developed as a promising technique for future gravity gradiometric missions after GOCE due to its greater sensitivity in micro-gravity environments and constant performance over the measurement bandwidth. In this paper, a feasible method of spaceborne atom-interferometry gravity gradiometry is proposed by utilizing the free-fall condition of the cold atoms in space. Compared with GOCE, which shows an in-orbit noise performance of 10~20 mE/Hz^1/2, the scheme described in this paper would achieve a high sensitivity of 1.9 mE/Hz^1/2 for gravity gradients measurement by reducing the orbital altitude and optimizing the interrogation time for atom interferometry. The results show that the proposed scheme could significantly augment the spectral content of the gravity field in the degree and order of 280~316 and resolve the global gravity field with an improved accuracy of 0.2 cm@100 km and 0.85 cm@80 km in terms of geoid height, and 0.06 mGal@100 km and 0.3 mGal@80 km in terms of gravity anomaly after 1270 days of data collection. Full article