Sentences with phrase «radionuclide reconstructions»

Not exact matches

The radionuclide signal reflects mainly production (Berggren et al. 2009), making them a useful tool of solar variability reconstructions in the past (Usoskin 2013).

Therefore, these variations are likely dominated by solar influence, as e.g. known for the last 500 years where a series of solar minima leads to erroneous low dipole field reconstructions using the radionuclide data.

The somewhat contradictory results for the similarity of radionuclide - based dipole reconstructions and geomagnetic field models on these time scales point out that geomagnetic field models have to be improved further before they can provide a truly robust means to eliminate the influence of geomagnetic variability in cosmogenic radionuclide production studies.

The variations of solar activity over long time intervals using a solar activity reconstruction based on the cosmogenic radionuclide 10Be measured in polar ice cores are studied.

The cosmogenic radionuclide records have been low - pass filtered by a rectangular function in the frequency domain with different cut - off frequencies in order to minimise the solar influence and to investigate the time scales on which we see common changes in the radionuclide production rates and the geomagnetic field intensity reconstructions.

The geomagnetic reconstructions shown in Figure 5 are also smoothed by their modelling methods, but with different filter characteristics than the radionuclide curves.

We used the higher resolution CALS3k.3 and CALS3k.4 dipole estimates for comparisons using the same filters on the geomagnetic and the radionuclide dipole reconstructions for the past 3 kyrs (Fig. 6), and computed the correlation coefficients among all four records for the time series with low - pass filters between 1/200 and 1/1000 yrs.

Figure 5 shows comparisons of the 1/1000 yr (a) and 1/3000 yr (b) low - pass filtered radionuclide records to the dipole moment reconstructions of CALS10k.1 b and the VADMs by Knudsen et al. (2008).

As seen in Figure 6, particularly the higher - frequency variations in the two radionuclide estimates agree rather well in phase and show higher amplitudes than the geomagnetic reconstructions, confirming the results by Snowball et al. (2007) that variations in radionuclide production rates on up to multi-centennial time scales are dominated by solar magnetic field variations.

Here we use a 9400 year solar activity reconstruction derived from cosmogenic radionuclides to test this hypothesis.