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On the Reduced Geoeffectiveness of Solar Cycle 24: A Moderate Storm PerspectiveThe moderate and intense geomagnetic storms are identified for the first 77 months of solar cycles 23 and 24. The solar sources responsible for the moderate geomagnetic storms are indentified during the same epoch for both the cycles. Solar cycle 24 has shown nearly 80% reduction in the occurrence of intense storms whereas it is only 40% in case of moderate storms when compared to previous cycle. The solar and interplanetary characteristics of the moderate storms driven by coronal mass ejection (CME) are compared for solar cycles 23 and 24 in order to see reduction in geoeffectiveness has anything to do with the occurrence of moderate storm. Though there is reduction in the occurrence of moderate storms, the Dst distribution does not show much difference. Similarly, the solar source parameters like CME speed, mass, and width did not show any significant variation in the average values as well as the distribution. The correlation between VBz and Dst is determined, and it is found to be moderate with value of 0.68 for cycle 23 and 0.61 for cycle 24. The magnetospheric energy flux parameter epsilon (epsilon) is estimated during the main phase of all moderate storms during solar cycles 23 and 24. The energy transfer decreased in solar cycle 24 when compared to cycle 23. These results are significantly different when all geomagnetic storms are taken into consideration for both the solar cycles.
Document ID
20170003095
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Selvakumaran, R. (Indian Inst. of Geomagnetism New Panvel, India)
Veenadhari, B. (Indian Inst. of Geomagnetism New Panvel, India)
Akiyama, S. (Catholic Univ. of America Washington, DC, United States)
Pandya, Megha (Indian Inst. of Geomagnetism New Panvel, India)
Gopalswamy, N, (NASA Goddard Space Flight Center Greenbelt, MD United States)
Yashiro, S. (Catholic Univ. of America Washington, DC, United States)
Kumar, Sandeep (Indian Inst. of Geomagnetism New Panvel, India)
Makela, P. (Catholic Univ. of America Washington, DC, United States)
Xie, H. (Catholic Univ. of America Washington, DC, United States)
Date Acquired
April 6, 2017
Publication Date
September 17, 2016
Publication Information
Publication: Journal of Geophysical Research: Space Physics
Volume: 121
Issue: 9
ISSN: 2169-9380
Subject Category
Solar Physics
Report/Patent Number
GSFC-E-DAA-TN40769
Funding Number(s)
CONTRACT_GRANT: NNG11PL10A
Distribution Limits
Public
Copyright
Other