10Be in last deglacial climate simulated by ECHAM5-HAM – Part I: climatological influences on 10Be deposition

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dc.contributor.authorHeikkilä, UEen_AU
dc.contributor.authorPhipps, SJen_AU
dc.contributor.authorSmith, AMen_AU
dc.date.accessioned2020-06-11T23:49:02Zen_AU
dc.date.available2020-06-11T23:49:02Zen_AU
dc.date.issued2013-11-25en_AU
dc.date.statistics220-06-01en_AU
dc.description.abstractReconstruction of solar irradiance has only been possible for the Holocene so far. During the last deglaciation, two solar proxies (10Be and 14C) deviate strongly, both of them being influenced by climatic changes in a different way. This work addresses the climate influence on 10Be deposition by means of ECHAM5-HAM atmospheric aerosol–climate model simulations, forced by sea surface temperatures and sea ice extent created by the CSIRO Mk3L coupled climate system model. Three time slice simulations were performed during the last deglaciation: 10 000 BP ("10k"), 11 000 BP ("11k") and 12 000 BP ("12k"), each 30 yr long. The same, theoretical, 10Be production rate was used in each simulation to isolate the impact of climate on 10Be deposition. The changes are found to follow roughly the reduction in the greenhouse gas concentrations within the simulations. The 10k and 11k simulations produce a surface cooling which is symmetrically amplified in the 12k simulation. The precipitation rate is only slightly reduced at high latitudes, but there is a northward shift in the polar jet in the Northern Hemisphere, and the stratospheric westerly winds are significantly weakened. These changes occur where the sea ice change is largest in the deglaciation simulations. This leads to a longer residence time of 10Be in the stratosphere by 30 (10k and 11k) to 80 (12k) days, increasing the atmospheric concentrations (25–30% in 10k and 11k and 100% in 12k). Furthermore the shift of westerlies in the troposphere leads to an increase of tropospheric 10Be concentrations, especially at high latitudes. The contribution of dry deposition generally increases, but decreases where sea ice changes are largest. In total, the 10Be deposition rate changes by no more than 20% at mid- to high latitudes, but by up to 50% in the tropics. We conclude that on "long" time scales (a year to a few years), climatic influences on 10Be deposition remain small (less than 50%) even though atmospheric concentrations can vary significantly. Averaged over a longer period, all 10Be produced has to be deposited by mass conservation. This dominates over any climatic influences on 10Be deposition. Snow concentrations, however, do not follow mass conservation and can potentially be impacted more by climate due to precipitation changes. Quantifying the impact of deglacial climate modulation on 10Be in terms of preserving the solar signal locally is analysed in an accompanying paper (Heikkilä et al., 10Be in late deglacial climate simulated by ECHAM5-HAM – Part 2: Isolating the solar signal from 10Be deposition). © Author(s) 2013.en_AU
dc.identifier.citationHeikkilä, U., Phipps, S. J., and Smith, A. M. (2013). 10Be in late deglacial climate simulated by ECHAM5-HAM – Part 1: climatological influences on 10Be deposition. Climate of the Past, 9(6), 2641-2649. doi:10.5194/cp-9-2641-2013, 2013.en_AU
dc.identifier.govdoc9679en_AU
dc.identifier.issn1814-9332en_AU
dc.identifier.issue6en_AU
dc.identifier.journaltitleClimate of the Pasten_AU
dc.identifier.pagination2641-2649en_AU
dc.identifier.urihttps://doi.org/10.5194/cp-9-2641-2013en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/9598en_AU
dc.identifier.volume9en_AU
dc.language.isoenen_AU
dc.publisherCopernicus Publicationsen_AU
dc.subjectClimatesen_AU
dc.subjectAntarcticaen_AU
dc.subjectQuaternary perioden_AU
dc.subjectGlaciersen_AU
dc.subjectBeryllium 10en_AU
dc.subjectAerosolsen_AU
dc.subjectSimulationen_AU
dc.subjectIceen_AU
dc.subjectIce capsen_AU
dc.subjectGreenhouse gasesen_AU
dc.subjectPolar regionsen_AU
dc.subjectStratosphereen_AU
dc.title10Be in last deglacial climate simulated by ECHAM5-HAM – Part I: climatological influences on 10Be depositionen_AU
dc.typeJournal Articleen_AU
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