Optimized strategy for the calibration of superconducting gravimeters at the one per mille level
- Author(s)
- Michel van Camp, Bruno Meurers, Oliver de Viron, Thomas Forbriger
- Abstract
This paper reports on different sources of errors that occur in the calibration process of a superconducting gravimeter (SG), determined by comparison with a ballistic absolute gravimeter (AG); some of them have never been discussed in the literature. We then provide methods to mitigate the impact of those errors, to achieve a robust calibration estimate at the [InlineEquation not available: see fulltext.] level. We demonstrate that a standard deviation at the level of [InlineEquation not available: see fulltext.] can be reached within 48 h by measuring at spring tides and by increasing the AG sampling rate. This is much shorter than what is classically reported in previous empirical studies. Measuring more than 5 days around a tidal extreme does not improve the precision in the calibration factor significantly, as the variation in the error as a function of (Formula presented.) does not apply, considering the decrease in signal amplitude due to the tidal modulation. However, we investigate the precision improvement up to 120 days, which can be useful if an AG is run continuously: at mid-latitude it would require 21 days to ensure a calibration factor at the [InlineEquation not available: see fulltext.] level with a 99.7 % confidence interval. We also show that restricting the AG measurement periods to tidal extrema can reduce instrument demand, while this does not affect the precision on the calibration factor significantly. Then, we quantify the effect of high microseismic noise causing aliasing in the AG time series. We eventually discuss the attenuation bias that might be induced by noisy time series of the SG. When experiments are performed at the [InlineEquation not available: see fulltext.] level, 7 are needed to ensure that the error in the calibration estimate will be at the 1 per mille level with a 99 % confidence.
- Organisation(s)
- Department of Meteorology and Geophysics
- External organisation(s)
- Royal Observatory of Belgium, Université de Paris, Karlsruher Institut für Technologie
- Journal
- Journal of Geodesy
- Volume
- 90
- Pages
- 91-99
- No. of pages
- 9
- ISSN
- 0949-7714
- DOI
- https://doi.org/10.1007/s00190-015-0856-7
- Publication date
- 01-2016
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105106 Geodynamics, 105111 Gravimetry, 105102 General geophysics
- Keywords
- ASJC Scopus subject areas
- Computers in Earth Sciences, Geochemistry and Petrology, Geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/optimized-strategy-for-the-calibration-of-superconducting-gravimeters-at-the-one-per-mille-level(77f322fb-c87f-4610-9a63-8728945012e3).html