Skip to Main content Skip to Navigation
Journal articles

Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano

Abstract : 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 (∅>20 µm) is observed, in association with oscillations of stable isotope records (δD, δ18O). 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.
Document type :
Journal articles
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-03706457
Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Tuesday, June 28, 2022 - 2:34:39 PM
Last modification on : Wednesday, June 29, 2022 - 10:49:11 AM

File

tc-15-1383-2021.pdf
Publisher files allowed on an open archive

Licence


Distributed under a Creative Commons Attribution 4.0 International License

Identifiers

Collections

IRD | INSU | UGA | CNRS | IGE

Citation

Filipe G. L. Lindau, Jefferson C. Simões, Barbara Delmonte, Patrick Ginot, Giovanni Baccolo, et al.. Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano. The Cryosphere, Copernicus 2021, 15, pp.1383-1397. ⟨10.5194/tc-15-1383-2021⟩. ⟨insu-03706457⟩

Share

Metrics

Record views

0

Files downloads

0