Open AccessPersistence in recurrent geomagnetic activity and its connection with Space Climate
Author(s) -
Diego P.,
Storini M.,
Laurenza M.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014716
Subject(s) - earth's magnetic field , autocorrelation , interplanetary spaceflight , space weather , physics , solar cycle , solar wind , series (stratigraphy) , solar cycle 23 , atmospheric sciences , astrophysics , meteorology , geology , mathematics , statistics , magnetic field , quantum mechanics , paleontology
Recurrent geomagnetic activity is mainly linked to the passage of interplanetary corotating solar wind structures in the near‐Earth space. We studied geomagnetic recurrences for which an enhanced value of the autocorrelation coefficient exists between the data of two adjacent Bartels rotations in aa, Kp, Dst, AE time series, for the period 1954–2007, covering about 5 solar cycles (from cycle 19 to cycle 23). A new index ( P ), based on autocorrelation analysis, has been introduced to estimate also the duration up to seven Bartels rotations of each solar structure (or group of structures) producing geomagnetic recurrences with high autocorrelation (correlation coefficient ≥ 0.3). We could infer whether recurrent geomagnetic activity is due to successive short‐lived (at least 2 Bartels rotations) or to long‐lasting corotating structures (up to 7 or more Bartels rotations). Generally, time periods characterized by recurrent geomagnetic activity are longer during the descending phase of even‐numbered cycles (20, 22). Nevertheless, we found that recurrences determined by long‐lived interplanetary structures are detected mainly in the descending phase of cycles 19 and 23. Finally, we point out that the average levels of the computed indices during the descending phase of each solar cycle show a significant anticorrelation with the sunspot area integrated over the subsequent cycle, giving new insights for Space Climate forecast.