What do cosmogenic isotopes tell us about past solar forcing of climate?
What do cosmogenic isotopes tell us about past solar forcing of climate?
In paleoclimate studies, cosmogenic isotopes are frequently used as proxy indicators of past variations in solar irradiance on centennial and millennial timescales. These isotopes are spallation products of galactic cosmic rays (GCRs) impacting Earth's atmosphere, which are deposited and stored in terrestrial reservoirs such as ice sheets, ocean sediments and tree trunks. On timescales shorter than the variations in the geomagnetic field, they are modulated by the heliosphere and thus they are, strictly speaking, an index of heliospheric variability rather than one of solar variability. Strong evidence of climate variations associated with the production (as opposed to the deposition) of these isotopes is emerging. This raises a vital question: do cosmic rays have a direct influence on climate or are they a good proxy indicator for another factor that does (such as the total or spectral solar irradiance)? The former possibility raises further questions about the possible growth of air ions generated by cosmic rays into cloud condensation nuclei and/or the modulation of the global thunderstorm electric circuit. The latter possibility requires new understanding about the required relationship between the heliospheric magnetic fields that scatter cosmic rays and the photospheric magnetic fields which modulate solar irradiance.
galactic cosmic rays, total solar irradiance, cosmogenic isotopes, paleoclimate changes
95-109
Lockwood, M.
32917473-f7d9-4773-9162-6509baad09fa
April 2006
Lockwood, M.
32917473-f7d9-4773-9162-6509baad09fa
Lockwood, M.
(2006)
What do cosmogenic isotopes tell us about past solar forcing of climate?
Space Science Reviews, 125 (1-4), .
(doi:10.1007/s11214-006-9049-2).
Abstract
In paleoclimate studies, cosmogenic isotopes are frequently used as proxy indicators of past variations in solar irradiance on centennial and millennial timescales. These isotopes are spallation products of galactic cosmic rays (GCRs) impacting Earth's atmosphere, which are deposited and stored in terrestrial reservoirs such as ice sheets, ocean sediments and tree trunks. On timescales shorter than the variations in the geomagnetic field, they are modulated by the heliosphere and thus they are, strictly speaking, an index of heliospheric variability rather than one of solar variability. Strong evidence of climate variations associated with the production (as opposed to the deposition) of these isotopes is emerging. This raises a vital question: do cosmic rays have a direct influence on climate or are they a good proxy indicator for another factor that does (such as the total or spectral solar irradiance)? The former possibility raises further questions about the possible growth of air ions generated by cosmic rays into cloud condensation nuclei and/or the modulation of the global thunderstorm electric circuit. The latter possibility requires new understanding about the required relationship between the heliospheric magnetic fields that scatter cosmic rays and the photospheric magnetic fields which modulate solar irradiance.
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Published date: April 2006
Keywords:
galactic cosmic rays, total solar irradiance, cosmogenic isotopes, paleoclimate changes
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Local EPrints ID: 38350
URI: http://eprints.soton.ac.uk/id/eprint/38350
ISSN: 0038-6308
PURE UUID: 720a4799-73d0-4762-8b1e-1fa131b101c6
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Date deposited: 27 Apr 2007
Last modified: 15 Mar 2024 08:06
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Author:
M. Lockwood
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