Solar cosmic ray events for the period 1561-1994, 2, The Gleissberg periodicity
Abstract. The geophysical significance of the thin nitrate-rich layers that have been found in both Arctic and Antarctic firn and ice cores, dating from the period 1561-1991, is examined in detail. It is shown that variations of meteorological origin dominate the record until the snow has consolidat...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.637.147 http://www.leif.org/EOS/Nitrate2.pdf |
| Summary: | Abstract. The geophysical significance of the thin nitrate-rich layers that have been found in both Arctic and Antarctic firn and ice cores, dating from the period 1561-1991, is examined in detail. It is shown that variations of meteorological origin dominate the record until the snow has consolidated to high-density firn some 30 years after deposition. The thin nitrate layers have a characteristic short timescale (<6 weeks) and are highly correlated with periods of major solar-terrestrial disturbance, the probability of chance correlation being less than 10-9. A one-to-one correlation is demonstrated between the seven largest solar proton fluence events that have been observed since continuous recording of the cosmic radiation started in 1936, and the corresponding thin nitrate layers for the event date. The probability of this occurring by chance is <10-ø. This high degree of statistical correlation, together with the modeling studies of Jackman, Vitt, and coworkers, is interpreted as establishing that the impulsive nitrate events are causally related to the generation of energetic particles by solar activity. The timescale of the nitrate events is too short to be understood in terms of transport mechanisms in the gaseous phase and indicates that the nitrate must be precipitated to the polar caps by the |
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