Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano
<p>A deeper understanding of past atmospheric circulation variability in the Central Andes is a high-priority topic in paleoclimatology mainly because of the necessity to validate climate models used to predict future precipitation trends and to develop mitigation and/or adaptation strategies...
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doaj-0156bfed01754ddeae55633869ba094b2021-03-16T10:16:13ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242021-03-01151383139710.5194/tc-15-1383-2021Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian AltiplanoF. G. L. Lindau0J. C. Simões1J. C. Simões2B. Delmonte3P. Ginot4G. Baccolo5C. I. Paleari6E. Di Stefano7E. Korotkikh8D. S. Introne9V. Maggi10E. Garzanti11S. Andò12Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501-970, BrazilCentro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501-970, BrazilClimate Change Institute, University of Maine, Orono, ME 04469, USADepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, ItalyUniv. Grenoble Alpes, CNRS, IRD, Grenoble INP, IGE, 38000 Grenoble, FranceDepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, ItalyDepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, ItalyDepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, ItalyClimate Change Institute, University of Maine, Orono, ME 04469, USAClimate Change Institute, University of Maine, Orono, ME 04469, USADepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, ItalyDepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, ItalyDepartment of Environmental and Earth Sciences, University of Milano-Bicocca, 20126 Milan, Italy<p>A deeper understanding of past atmospheric circulation variability in the Central Andes is a high-priority topic in paleoclimatology mainly because of the necessity to validate climate models used to predict future precipitation trends and to develop mitigation and/or adaptation strategies for future climate change scenarios in this region. Within this context, we here investigate an 18-year firn core drilled at Nevado Illimani in order to interpret its mineral dust record in relation to seasonal processes, in particular atmospheric circulation and deep convection. The core was dated by annual layer counting based on seasonal oscillations of dust, calcium, and stable isotopes. Geochemical and mineralogical data show that dust is regionally sourced in winter and summer. During austral summer (wet season), an increase in the relative proportion of giant dust particles (<span class="inline-formula"><i>∅</i>>20</span> <span class="inline-formula">µm</span>) is observed, in association with oscillations of stable isotope records (<span class="inline-formula"><i>δ</i></span>D, <span class="inline-formula"><i>δ</i><sup>18</sup></span>O). It seems that at Nevado Illimani both the deposition of dust and the isotopic signature of precipitation are influenced by atmospheric deep convection, which is also related to the total amount of precipitation in the area. This hypothesis is corroborated by regional meteorological data. The interpretation of giant particle and stable isotope records suggests that downdrafts due to convective activity promote turbulent conditions capable of suspending giant particles in the vicinity of Nevado Illimani. Giant particles and stable isotopes, when considered together, can be therefore used as a new proxy for obtaining information about deep convective activity in the past.</p>https://tc.copernicus.org/articles/15/1383/2021/tc-15-1383-2021.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
F. G. L. Lindau J. C. Simões J. C. Simões B. Delmonte P. Ginot G. Baccolo C. I. Paleari E. Di Stefano E. Korotkikh D. S. Introne V. Maggi E. Garzanti S. Andò |
spellingShingle |
F. G. L. Lindau J. C. Simões J. C. Simões B. Delmonte P. Ginot G. Baccolo C. I. Paleari E. Di Stefano E. Korotkikh D. S. Introne V. Maggi E. Garzanti S. Andò Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano The Cryosphere |
author_facet |
F. G. L. Lindau J. C. Simões J. C. Simões B. Delmonte P. Ginot G. Baccolo C. I. Paleari E. Di Stefano E. Korotkikh D. S. Introne V. Maggi E. Garzanti S. Andò |
author_sort |
F. G. L. Lindau |
title |
Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano |
title_short |
Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano |
title_full |
Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano |
title_fullStr |
Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano |
title_full_unstemmed |
Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano |
title_sort |
giant dust particles at nevado illimani: a proxy of summertime deep convection over the bolivian altiplano |
publisher |
Copernicus Publications |
series |
The Cryosphere |
issn |
1994-0416 1994-0424 |
publishDate |
2021-03-01 |
description |
<p>A deeper understanding of past atmospheric circulation variability in the Central Andes is a high-priority topic in paleoclimatology mainly because of the necessity to validate climate models used to predict future precipitation trends and to develop mitigation and/or adaptation strategies for future climate change scenarios in this region. Within this context, we here investigate an 18-year firn core drilled at Nevado Illimani in order to interpret its mineral dust record in relation to seasonal processes, in particular atmospheric circulation and deep convection. The core was dated by annual layer counting based on seasonal oscillations of dust, calcium, and stable isotopes. Geochemical and mineralogical data show that dust is regionally sourced in winter and summer. During austral summer (wet season), an increase in the relative proportion of giant dust particles (<span class="inline-formula"><i>∅</i>>20</span> <span class="inline-formula">µm</span>) is observed, in association with oscillations of stable isotope records (<span class="inline-formula"><i>δ</i></span>D, <span class="inline-formula"><i>δ</i><sup>18</sup></span>O). It seems that at Nevado Illimani both the deposition of dust and the isotopic signature of precipitation are influenced by atmospheric deep convection, which is also related to the total amount of precipitation in the area. This hypothesis is corroborated by regional meteorological data. The interpretation of giant particle and stable isotope records suggests that downdrafts due to convective activity promote turbulent conditions capable of suspending giant particles in the vicinity of Nevado Illimani. Giant particles and stable isotopes, when considered together, can be therefore used as a new proxy for obtaining information about deep convective activity in the past.</p> |
url |
https://tc.copernicus.org/articles/15/1383/2021/tc-15-1383-2021.pdf |
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