Continued decline of South Pole neutron monitor counting rate

被引:13
作者
Bieber, John [1 ]
Clem, John [1 ]
Evenson, Paul [1 ]
Oh, Suyeon [2 ]
Pyle, Roger [1 ]
机构
[1] Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA
[2] Chungnam Natl Univ, Dept Astron & Space Sci, Taejon, South Korea
基金
美国国家科学基金会; 新加坡国家研究基金会;
关键词
Neutron Monitor; Cosmic Ray; Geomagnetic Cutoff; Solar Modulation; Radiation Background; MODULATION;
D O I
10.1002/2013JA018915
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The counting rate of a neutron monitor at South Pole, Antarctica, displays a long-term decline over the 49year span from March 1964 to the present. The counting rate follows an 11year cycle with maxima at times of low solar activity. However, after adjusting for the unusually high overall cosmic ray fluxes in 2009, we find that the 2009 peak rate (based on 27 day averages) was approximately 10% lower than the 1965 peak rate. This change is much larger than that recorded by any other neutron monitor. We suggest that the South Pole monitor, owing to its unique position at both high latitude and high altitude may have a hitherto unsuspected sensitivity to secular changes in the magnetic field of the Earth.
引用
收藏
页码:6847 / 6851
页数:5
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