Stéphane Alfaro

Prof. Dr. Stéphane Alfaro


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2014 in Aeolian Research
Verified
Journal Article
Closed access
SLSandra Lafon
Sandra Lafon
SAStéphane Alfaro
Stéphane Alfaro
SCServanne Chevaillier
Servanne Chevaillier
JRJean Louis RAJOT
Jean Louis RAJOT


2 October 2018 in Journal of Geophysical Research: Atmospheres
Verified
Journal Article
Open access
PDF file
GBG. Bergametti
G. Bergametti
BMB. Marticorena
B. Marticorena
JRJean Louis RAJOT
Jean Louis RAJOT
GFG. Foret
G. Foret
SAStéphane Alfaro
Stéphane Alfaro
BLB. Laurent
B. Laurent
Bulk and size‐resolved particle concentrations were measured at 2.1 and 6.5 m above the soil surface during an intense dust deposition event that occurred in June 2006 in Niger. Bulk concentration measurements were performed using two tapered element oscillating microbalance instruments, and the size‐resolved particle concentrations (from 0.3 to 20 μm) using two optical particle counters. The deposition fluxes derived from the bulk concentrations and those derived from the size‐resolved ones are in very good agreement. The largest deposition fluxes are recorded when the dust concentrations are maximal. The temporal evolution of the dust deposition flux follows that of the dust concentration. This is not the case of the dry deposition velocities that are most of the time controlled by the wind friction velocity. The results also show that large particles are strongly sensible to rebound when the wind friction velocity is the highest. Size‐resolved dry deposition velocities are compared with the rare measurements of dust deposition velocities over bare sandy soils and are confronted to existing parameterizations of the dry deposition velocity. The parameterization of Zhang and Shao (2014, https://doi.org/10.5194/acp‐14‐12429‐2014) appears to be the only one able to reproduce satisfyingly the measured dry deposition velocities on sandy soils in the 1‐ to 10‐μm particle size range. Indeed, unlike others, this scheme considers the desert sandy surfaces as rough surfaces, allowing the interception of dust particles by the sand grains and/or by the small roughness elements present on the surface.

20 November 2023 in Meteorology and Atmospheric Physics
Verified
Journal Article
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M. H. ElTaweelM. H. ElTaweel
M. H. ElTaweel
SAStéphane Alfaro
Stéphane Alfaro
GSGuillaume Siour
Guillaume Siour
ACA. Coman
A. Coman
Prof. El Sayed M. RobaaProf. El Sayed M. Robaa
Prof. El Sayed M. Robaa
MAMagdy Abdelwahab
Magdy Abdelwahab

23 March 2023 in Atmosphere
Verified
Journal Article
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CFCarolina Loreto Gómez Fontealba
Carolina Loreto Gómez Fontealba
VFValentina Flores-Aqueveque
Valentina Flores-Aqueveque
SAStéphane Alfaro
Stéphane Alfaro
The Southern Westerly Wind (SWW) belt is one of the most important atmospheric features of the Southern Hemisphere (SH). In Patagonia, these winds control the precipitation rates at the windward side of the southern Andes, and rainfall is very sensitive to any change (strength and/or latitudinal position) in the wind belt. The present-day behavior of the SWW, also known as westerlies, is characterized by remarkable seasonality. This wind belt also varies at interannual-to-decadal time scales, associated with the influence of atmospheric phenomena such as the El Niño–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), respectively. Moreover, during the past few decades, the westerlies have shown an increase in their core strength influenced by changes in the Southern Annular Mode (SAM). However, what controls the long-term variability of the SWW at the high latitudes of the SH is still a matter of debate. This work statistically analyzes the influence of large-scale modes of variability, such as ENSO and PDO on the SAM and the frequency of the strong SWW from ERA5 reanalysis data of southwestern Patagonia (~51°S), where the current core of this belt is located. Our results confirm the relation between strong wind anomalies and the SAM. In addition, the temporal variations of strong winds are also significantly affected by the PDO, but there is no detectable influence of the ENSO on their frequency. This shows that future studies focused on reconstructing wind history from aeolian particles of lake sediments from southwestern Patagonia could also provide information about the modes of variability that influence strong wind frequency.

27 January 2022 in Atmosphere
Verified
Journal Article
Open access
PDF file
CFCarolina Loreto Gómez Fontealba
Carolina Loreto Gómez Fontealba
VFValentina Flores-Aqueveque
Valentina Flores-Aqueveque
SAStéphane Alfaro
Stéphane Alfaro
The Southern Hemisphere Westerly Winds (SWW) control the amount and latitudinal distribution of rainfall in southwestern Patagonia. Recent studies have shown that SWW has intensified in the last decades, but their past behavior is not yet well understood. To understand this behavior, it is necessary to analyze climatic data from meteorological stations and reconstruct their variability through paleoclimatic evidence, such as lake cores. Nevertheless, Patagonia is an austral region characterized by its complex topography and quasi lack of a meteorological network. In this work, three reanalyses are studied (MERRA-2, ERA5, and GLDAS) and compared with the Cerro Castillo and Teniente Gallardo stations (~51°S), with the aim of simulating the winds in the past. The results indicate that ERA5 and MERRA-2 simulate well the wind variability in the study region, while GLDAS is less reliable. Therefore, the first two reanalyses could be used to extend the time series of the meteorological station and calibrate a new wind proxy based on the abundance and size of the aeolian particles, reconstructing in a direct way the intensity of the SWW in the past over southwestern Patagonia.