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Indian Journal of Radio & Space Physics (IJRSP) >
IJRSP Vol.39 [2010] >
IJRSP Vol.39(5) [October 2010] >
| Title: | Effect of solar wind speed variations on other interplanetary parameters |
| Authors: | Dwivedi, Vidya Charan
Pandey, V S
Tiwari, D P
Agrawal, S P |
| Keywords: | Solar wind
Interplanetary magnetic field
Geomagnetic field
Correlation study |
| Issue Date: | Oct-2010 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 96.60.Vg; 96.50.Bh |
| Abstract: | The daily values of interplanetary solar wind parameters as well as
that of the geomagnetic disturbance index (Ap) have been used for the years 1965-2006.
Long-term averages have been calculated for all those days when simultaneous
data is available for all these parameters (V, B, Bz and Ap). Earlier reports
have usually underlined the importance of V in producing terrestrial effects.
As such, individual days have been grouped, in accordance with the limited
range of V, in seven groups by the method of iteration using K-mean clustering
(data mining) technique. Having selected days in each of the seven groups
(ranges), the group averages, have been calculated for the entire period for V,
B, VB and Ap along with their standard errors. The method has been further
repeated for the individual solar cycles. These group averages have been used
to investigate the statistical relationships between V, B, VB and Ap in
different combinations. The results so obtained can be summarized as: (i) the
monotonic increase of group average V is almost similar to that of increasing
average values of Ap, and VB from groups 1 to 7; (ii) For each of the seven
groups, VB vs Ap and B vs Ap have been always found to be
better correlated (‘r’ larger) on a day-to-day basis, whereas V vs Ap has low values of ‘r’; (iii) the
direction of Bz when negative is very much effective in producing larger Ap as
compared to days when Bz is positive, in all the seven groups (more prominently
in the last four groups of larger V). The statistical results obtained signify
that the product VB is very effective in producing large scale geomagnetic
disturbances. |
| Page(s): | 252-256 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.39(5) [October 2010]
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