| 1. |
- Benella, Simone, et al.
(författare)
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Kramers-Moyal analysis of interplanetary magnetic field fluctuations at sub-ion scales
- 2022
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Ingår i: Rendiconti Lincei SCIENZE FISICHE E NATURALI. - : Springer Nature. - 2037-4631 .- 1720-0776. ; 33:4, s. 721-728
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of statistical time series analysis of complex dynamics, we present a multiscale characterization of solar wind turbulence in the near-earth environment. The data analysis, based on the Markov process theory, is meant to estimate the Kramers-Moyal coefficients associated with the measured magnetic field fluctuations. In fact, when the scale-to-scale dynamics can be successfully described as a Markov process, first- and second-order Kramers-Moyal coefficients provide a complete description of the dynamics in terms of Langevin stochastic process. The analysis is carried out using high-resolution magnetic field measurements gathered by Cluster during a fast solar wind period on January 20, 2007. This analysis extends recent findings in the near-Sun environment with the aim of testing the universality of the Markovian nature of the magnetic field fluctuations in the sub-ion/kinetic domain.
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| 2. |
- Raffi, Isabella, et al.
(författare)
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The role of calcareous nannofossils in building age models for Cenozoic marine sediments : a review
- 2022
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Ingår i: Rendiconti Lincei SCIENZE FISICHE E NATURALI. - : Springer Science and Business Media LLC. - 2037-4631 .- 1720-0776. ; 33:1, s. 25-38
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Forskningsöversikt (refereegranskat)abstract
- This review paper has been thought to emphasize the role of Biostratigraphy in Geosciences and, specifically, of calcareous nannofossils as dating tool. This group of calcareous plankton occurs in Mesozoic and Cenozoic carbonate-bearing marine sediments in all depositional settings and is routinely used for stratigraphic purposes. The importance of calcareous nannofossils in relative dating of marine sediments is due to their abundance, taxonomic diversity, rapid evolution and wide distribution in marine environments. Nannofossil biostratigraphy improved over the last few decades due to the use of accurate methods for data gathering, including acquisition of semiquantitative census data on high-resolution samples. These microfossils contribute to obtain reliable biostratigraphic classification in various time-intervals in the last 66 m.y. and often provide the key to the interpretation of other stratigraphic records. Nannofossil biohorizons can be used as control points for constructing cyclostratigraphic composite sections, and for identification of magnetostratigraphic intervals, and have provided a basis for age models subsequently developed into orbitally tuned cyclostratigraphies or used for chronological revision of polarity timescale.
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