Article thumbnail


By W. R. Webber and P. R. Higbie


Using new calculations of 10 Be production in the Earths atmosphere which are based on direct measurements of the 11-year solar modulation effects on galactic cosmic rays and spacecraft measurements of the cosmic ray energy spectrum, we have calculated the yearly average production of 10 Be in the Earths atmosphere by galactic and solar cosmic rays since 1939. During the last six 11-year cycles the average amplitude of these production changes is 36%. These predictions are compared with measurements of 10 Be concentration in polar ice cores in both the Northern and Southern hemisphere over the same time period. We find a large scatter between the predicted and measured yearly average data sets and a low cross correlation ~0.30. Also the normalized regression line slope between 10 Be production changes and 10 Be concentration changes is found to be only 0.4-0.6; much less than the value of 1.0 expected for a simple proportionality between these quantities, as is typically used for historical projections of the relationship between 10 Be concentration and solar activity. The distribution of yearly averages in the 10 Be concentration level in the data from the Dye-3 ice core in Greenland for the time period 1939-1985, contains a "spike " of high concentration one year averages which is not seen in the production calculations. These and other features suggest that galactic cosmic ray intensity changes which affect the production of 10 Be in the Earths atmosphere are not the sole source of the 10 Be concentration changes and confirm the importance of other effects, for example local and regional climatic effects, which could be of the same magnitude as the 10 Be production changes. 39 3 4

Year: 2013
OAI identifier: oai:CiteSeerX.psu:
Provided by: CiteSeerX
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • (external link)
  • (external link)
  • Suggested articles

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.