ORCID Profile
0000-0001-8183-0310
Current Organisations
Indiana University Bloomington
,
Consejo Nacional de Investigaciones Científicas y Técnicas
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Publisher: Springer Science and Business Media LLC
Date: 21-07-1997
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TA90280C
Publisher: Springer Science and Business Media LLC
Date: 30-11-2017
Publisher: Springer Science and Business Media LLC
Date: 30-03-2014
DOI: 10.1038/NCLIMATE2174
Publisher: Springer Science and Business Media LLC
Date: 21-04-2013
DOI: 10.1038/NGEO1797
Publisher: Springer Science and Business Media LLC
Date: 28-10-2012
DOI: 10.1038/NGEO1613
Publisher: Springer Science and Business Media LLC
Date: 04-03-1998
Publisher: Wiley
Date: 09-2017
DOI: 10.1002/ECS2.1932
Publisher: Springer Science and Business Media LLC
Date: 17-12-2018
DOI: 10.1038/S41467-018-07636-6
Abstract: The original version of this Article contained an error in the Data Availability section, which incorrectly read ‘All data will be freely available via www.ams.ethz.ch/research.html .’ The correct version states ‘ www.ams.ethz.ch/research ublished-data.html ’ in place of ‘ www.ams.ethz.ch/research.html ’. This has been corrected in both the PDF and HTML versions of the Article.
Publisher: Springer Science and Business Media LLC
Date: 06-09-2018
DOI: 10.1038/S41467-018-06036-0
Abstract: Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14 C content in 484 in idual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct 14 C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved 14 C measurements are needed.
Publisher: SAGE Publications
Date: 2009
Abstract: This review of late-Holocene palaeoclimatology represents the results from a PAGES/CLIVAR Intersection Panel meeting that took place in June 2006. The review is in three parts: the principal high-resolution proxy disciplines (trees, corals, ice cores and documentary evidence), emphasizing current issues in their use for climate reconstruction the various approaches that have been adopted to combine multiple climate proxy records to provide estimates of past annual-to-decadal timescale Northern Hemisphere surface temperatures and other climate variables, such as large-scale circulation indices and the forcing histories used in climate model simulations of the past millennium. We discuss the need to develop a framework through which current and new approaches to interpreting these proxy data may be rigorously assessed using pseudo-proxies derived from climate model runs, where the `answer' is known. The article concludes with a list of recommendations. First, more raw proxy data are required from the erse disciplines and from more locations, as well as replication, for all proxy sources, of the basic raw measurements to improve absolute dating, and to better distinguish the proxy climate signal from noise. Second, more effort is required to improve the understanding of what in idual proxies respond to, supported by more site measurements and process studies. These activities should also be mindful of the correlation structure of instrumental data, indicating which adjacent proxy records ought to be in agreement and which not. Third, large-scale climate reconstructions should be attempted using a wide variety of techniques, emphasizing those for which quantified errors can be estimated at specified timescales. Fourth, a greater use of climate model simulations is needed to guide the choice of reconstruction techniques (the pseudo-proxy concept) and possibly help determine where, given limited resources, future s ling should be concentrated.
Publisher: Elsevier BV
Date: 04-2018
Location: United States of America
Location: United States of America
Location: Argentina
No related grants have been discovered for Ricardo Villalba.