Open AccessNew Insights on Cosmic Ray Modulation through a Joint Use of Nonstationary Data-Processing Methods
Author(s) -
A. Vecchio,
Monica Laurenza,
M. Storini,
V. Carbone
Publication year - 2012
Publication title -
advances in astronomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 34
eISSN - 1687-7977
pISSN - 1687-7969
DOI - 10.1155/2012/834247
Subject(s) - physics , heliosphere , neutron monitor , cosmic ray , astrophysics , sunspot number , sunspot , solar cycle , modulation (music) , maxima , polarity symbols , atmospheric sciences , nuclear physics , solar wind , magnetic field , plasma , art , quantum mechanics , acoustics , performance art , art history , breakdown voltage , voltage
The time variability of the cosmic ray (CR) intensity, recorded by the Climax neutron monitor and covering the period 1953–2004, has been analyzed by the joint application of the wavelet and the empirical mode decomposition (EMD) analyses. Dominant time scales of variability are found at ~11 yr, ~22 yr, ~6 yr and in the range of the quasi-biennial oscillations (QBOs). The combination of the 11 yr cycle and QBOs explains the Gnevychev Gap (GG) phenomenon and many step-like decreases characterizing the CR modulation. The additional scales of variability at ~22 yr and ~6 yr are responsible for other features of the long-term CR trend, such as the intensity flat-topped profile, following the maxima of even-numbered cycles during positive polarity state of the heliosphere (). Comparison with basic time scales of variability derived from the sunspot area (SA) allows the association of the 11 yr cycle and QBOs with solar activity variations, whereas the other two modes with the drift effects govern the CR entrance inthe heliosphere
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom