59 research outputs found
Large-scale strain-rates in Europe derived from observations in the European geodetic VLBI network
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Dissociation of lipotoxicity and glucotoxicity in a mouse model of obesity associated diabetes: role of forkhead box O1 (FOXO1) in glucose-induced beta cell failure
Astrometry and geodesy with radio interferometry: experiments, models, results
Summarizes current status of radio interferometry at radio frequencies
between Earth-based receivers, for astrometric and geodetic applications.
Emphasizes theoretical models of VLBI observables that are required to extract
results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the
achievements of VLBI during the past two decades in reference frames, Earth
orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys.,
Vol. 70, Oct. 199
Crustal motion results derived from observations in the European geodetic VLBI network
European multicenter study on LOH of APOC3 at 11q23 in 766 breast cancer patients: relation to clinical variables
The influence of 5000 year-old and younger glacial mass variability on present-day crustal rebound in the Antarctic Peninsula
Observed secular gravity trend at Onsala station with the FG5 gravimeter from Hannover
Annual absolute gravity measurements with a
FG5 instrument were performed in Onsala Space Observatory
by the Institute of Geodesy of the Leibniz Universität
Hannover from 2003 to 2011 and have been continued with
the upgraded meter FG5X in 2014. Lantmäteriet, Gävle,
with their FG5 absolute gravimeter have visited Onsala
since 2007. Because small systematic errors may be inherent
in each absolute gravimeter, their measuring level and
a resulting bias (offset) between the instruments must be
controlled over time by means of inter-comparison. From
2007 to 2014, 8 direct comparisons took place well distributed
over the time span. A complete re-processing of
the absolute gravity observations with the Hannover instrument
has been conducted to improve the reduction of
unwanted gravity effects. A new tidal model is based on
continuous time series recorded with the GWR superconducting
gravimeter at Onsala since 2009. The loading effect
of the Kattegat is described with a varying sea bottom
pressure (water and air mass load) and has been validated
with the continuous gravity measurements. For the
land uplift,which is a result of the still ongoing glacial isostatic
adjustment in Fennoscandia, a secular gravity trend
of −0.22 μGal/yr was obtained with a standard deviation
of 0.17 μGal/yr. That indicates a slight uplift but is still not
significantly different from zero
Analysis of atmospheric loading computations
Modeling computations show that atmospheric loading can cause vertical displacements with a amplitude of 2-5 mm. The uncertainty associated to these computations can also be in the order of a few mm. There are, in fact, errors and artifacts in the surface pressure data, in the inverted barometer assumption and discrepancies on how the data are treated by the different softwares. These effects, for different reasons, limit the accuracy of loading predictions both in the long and short-term. Additionally, there is the problem of the reference frame in which the displacements must be presented: a
frame fixed to the solid Earth or one fixed to the centre of mass of the combined solid Earth/atmosphere system.
Although, at the moment, the GPS noise level on the estimate of the vertical component is still at the level of a few to several mm for daily solutions, it is important to improve the atmospheric loading computations in view of future GPS noise level reductions. In particular, efforts shall be undertaken to compare the results of different software packages. Examples are the atmospheric pressure loading time series available at the IERS Special Bureau for Loading, those provided by the NASA Goddard VLBI group and the time series obtained with the software packages OLFG and
CARGA. The differences will be quantified and, where possible, the source of the discrepancies will be identified
Ocean tide loading displacements in western Europe: 2. GPS‐observed anelastic dispersion in the asthenosphere
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