[Todos] [Coloquios] ***HOY*** Coloquios DCAO/CIMA - VIERNES (14/04/2023) 10:30hs: PRESENCIAL

[coloquios en cima.fcen.uba.ar]

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Coloquios del Departamento de Ciencias de la Atmósfera y los Océanos 
(DCAO)/
Centro de Investigaciones del Mar y la Atmósfera (CIMA)
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Bienvenidos a la temporada 2023 de los Coloquios CIMA/DCAO. En el marco 
del proyecto ClimatAmSud "Andean Dust from sources to Sink" liderado por 
F. De Vleeschouwer en el IFAECI nos visitan 3 científicos especialistas 
en transporte, medición y modelización del polvo atmosférico pasado, 
presente y futuro. Aprovechamos esta oportunidad para invitarlos a una 
mañana extraordinaria de tres seminarios!

VIERNES 14/04, a las 10:30hs:

***Presencial: Aula 8 (CIMA, Pab II, 2do piso)******
*** Estaremos sirviendo café recién hecho - les invitamos a traer su 
taza ***

Para los que no pueden acercarse, el link de zoom correcto es el 
siguiente:
https://cnrs.zoom.us/j/92279615904?pwd=cXcwVWlXYkRxOWNUM09Gc3dieGp4Zz09
ID de reunión: 922 7961 5904
Código de acceso: 9E10ja

“Dust modeling since the Last Glacial Maximum" - Dr Fabrice Lambert 
(Pontificia Universidad Católica de Chile)

Abstract: Mineral dust aerosols scatter and absorb solar and thermal 
radiation, act as ice and cloud condensation nuclei, darken snowy 
surfaces after deposition, and play an important role in biogeochemical 
cycles both on land and in the ocean. Emitted in deserts and semi-arid 
regions, dust particles are entrained in the atmosphere by surface winds 
and reach the higher levels of the troposphere through ascending air 
currents, from there they can be transported across the globe. Dust 
particles are removed from the air by both dry (gravitational settling) 
and wet (washout through precipitation) deposition processes. Unlike 
well-mixed greenhouse gases, the climatic effects of dust vary 
seasonally and regionally and are not well represented by global 
averages.
Paleoclimate model simulations of dust emissions, load, direct radiative 
effects, and impacts on the carbon cycle through iron fertilization are 
accompanied by a large uncertainty. The large spread in model results 
can mainly be attributed to differences in the representation of dust 
emission and deposition mechanisms, differences in boundary conditions 
(including vegetation), inclusion of glaciogenic (formed by glacier 
abrasion) dust sources, different aerosol size ranges and optical 
properties, and assumptions about dustborne iron solubility and 
bioavailability. In this talk we will go through the lates advances in 
paleodust modeling and the main uncertainties that still impede 
paleoclimatic simulations of atmospheric dust, and how to address some 
of them.

Fabrice Lambert es académico del Instituto de Geografía de la Pontificia 
Universidad Católica de Chile. Doctor en física climática en la 
Universidad de Berna, Suiza, utiliza herramientas estadísticas avanzadas 
para investigar la variabilidad climática anual a milenial del 
hemisferio sur sobre la base de registros de alta resolución 
provenientes de diversos archivos paleoclimáticos. Sus intereses de 
investigación incluyen la evolución espacial y temporal de las 
concentraciones de polvo en la atmósfera durante la última transición 
glacial-interglacial y las estimaciones de forzamiento radiativo del 
polvo y fertilización de hierro del océano durante este intervalo de 
tiempo. Su investigación incluye trabajos de terreno, de laboratorio, y 
de simulaciones con modelos.

"Holocene mineral dust and ash deposition in the Western South Atlantic 
Ocean reconstructed from a Malvinas Island peat record" - Dr. Eleonore 
Resongles (IRD, Bolivia)

Abstract: Accurate reconstructions of past variations in long-range 
transport of dust and subsequent deposition to the remote Sub-Antarctic 
and Southern Oceans are central to our ability to understand the Earth 
system processes that drive changes of marine productivity and 
atmospheric carbon cycle in this region critical  for the global 
climate. In this talk, I will present a terrestrial record of volcanic 
ash and mineral dust deposition in the western South Atlantic Ocean 
using a 4 m-long peat core sampled in the Malvinas Islands covering the 
Late Glacial and Holocene periods. The main objectives of this study 
were to identify and quantify changes in dust sources and accumulation 
rates using geochemical fingerprinting.

Eléonore Resongles is a researcher at the French National Research 
Institute for Sustainable Development (IRD) at the laboratory 
HydroSciences Montpellier (France). She is currently hosted at the 
Instituto de Investigaciones Químicas (IIQ) at the University Mayor San 
Andres (La Paz, Bolivia). She has a PhD in Environmental Geochemistry 
from the University of Montpellier (France). Her research mainly focuses 
on assessing the impact of anthropogenic activities, in particular 
mining, on the cycling of metals and metalloids in the environment at 
different spatial (local and regional) and temporal scales (i.e. 
present, industrial era, Holocene) in different environmental 
compartments (rivers, atmosphere). She has a special interest in 
reconstructing atmospheric deposition of mineral dust and metal during 
the Holocene using environmental archives .

"Contributions to the study of southern hemisphere Late Pleistocene 
climatic variability through the characterization of South American dust 
sources and the related sedimentary deposits" - Dr Diego Gaiero 
(CICTERRA, Cordoba)

Abstract: The need to increase knowledge in aspects related to the 
climatic conditions prevailing over the southern hemisphere (SH) during 
the last glacial-interglacial periods, boosted the interest of the 
scientific community to investigate the physicochemical/isotopic 
characteristics of sediments deflated from southern South America (SSA) 
and to recognize them in key sedimentary deposits of the region (e.g., 
Pampas, Patagonian shelf, Southern Ocean; Antarctica). Due to its 
geographic position, SSA represents a key area that could help to 
unravel some questions related to past climatic changes. In particular, 
the region has the most significant loess deposits in the SH and, this 
proximal aeolian dust record witnesses the importance of wind erosion 
affecting different latitudinal and topographic areas in the "arid 
diagonal" of SSA, and could shed light on the past atmospheric 
circulation over the SH. Furthermore, a huge amount of this aeolian 
material has been atmospherically transported to remote areas, taking 
both essential micronutrients to the ocean and a fingerprint 
representing a particular SSA region, useful to trace back the origin of 
dust in paleo-climatic archives recovered from the Southern Ocean and 
Antarctica. During the last 20 years, we gained insight into aspects 
related to modern/past dust dynamics in the region, characterizing its 
textural, chemical/isotopic compositions and, contributing to the 
interpretation of how the atmospheric circulation over the region could 
have changed during the last climatic cycles. In this talk, I present a 
review of these research activities showing the main results obtained by 
our group and pointing out the futures perspectives that could help the 
international scientific community working on this issue to improve the 
state-of-the-art related to the role of the SH in the context of global 
future climate change scenarios.

Diego Gaiero s a full Professor at the University of Córdoba and a 
researcher at CONICET. He obtained a degree in Geology and then a Ph.D. 
degree at the same university. He is interested in low-temperature 
geochemistry processes and present/past atmospheric circulation. Since 
2003 he established a long-term dust monitoring program in southern 
South America. In 2014, he started a new research line dedicated to 
studying Argentinean loess as a geological archive.

¡¡Les esperamos!!

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Grupo Coloquios DCAO/CIMA
Departamento de Ciencias de la Atmósfera y los Océanos (FCEN-UBA)
Centro de Investigaciones del Mar y la Atmósfera (CONICET-UBA)
Ciudad Universitaria, Pabellón II, 2do piso.
email: coloquios en cima.fcen.uba.ar
http://www.at.fcen.uba.ar/charlas_not.php
http://www.cima.fcen.uba.ar/coloquios.php

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