Active remote sensing for atmospheric aerosol measurements: General presentation and UPC system description20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Variability of Mediterranean aerosols properties at three regional background sites in the western Mediterranean Basin
Michaël Sicard
Universitat Politècnica de Catalunya, Barcelona
msicard@tsc.upc.edu
Presented at SPIE Remote Sensing 2014
20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Co-authors
[IPSL/LSCE, Gif-sur-Yvette, France]
[RSLab/UPC, Barcelona, Spain]
[UGR/IISTA-CEAMA, Granada, Spain]
[LPCE, Orléans, France]
20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Objectives
SW–NE gradients
Provide some some inputs to ChArMEx questions on the:
Contribution of long range transport on the local air quality
Ageing of continental air masses above the Basin
WMB
20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Sites and instruments
AERONET: 6/11-1/12
AERONET: 2011-2013
AERONET: 2011-2013
20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
AOD at 440 nm and AE440-870
Ersa
Palma
Alborán
AOD marked annual cycle
The background AOD in winter/spring at Ersa is dominated by small particles located in the marine boundary layer, present throughout the year, while at Palma the predominance of the Atlantic advection meteorological scenario in winter/spring owns to the renovation of air masses at regional scale and to the cleaning of the atmosphere
AE no marked annual cycle, but a SW-NE gradient
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Size distribution & coarse mode fraction
SD - Seasonal variations
0,51
0,21
0,35
Coarse mode: clear SW-NE gradient
Coarse mode fraction: clear SW-NE gradient, especially in summer
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
AAOD
Ersa
Palma
Alborán
Summer means similar at Ersa and Alborán
It is double at Palma (→ pollutants from the nearby city of Palma de Mallorca?)
0,016
0,043
0,019
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Real and imaginary part of the RI
Ersa
Palma
Alborán
1,44
1,44
1,44
2,2
4,7
1,5
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
SSA and asymmetry factor
0,92<SSA440<0,98 → the 3 sites are moderately absorbing
SSA increases with increasing λ → behavior typical of mineral dust [Dubovik et al., JAS2002]
Ersa
Palma
Alborán
0,96
0,92
0,97
0,69
0,69
0,74
the SSA increases with increasing wavelengths. According to [15], this trend is a signature of mineral dust which allows us to conclude that the SSA in those three relatively clean sites is governed by mineral dust.
The high values found in Alborán are attributable to a marine environment according to
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Radiative forcing and forcing efficiency
Correction applied accordingly to García et al. (JGR2008) at the surface:
The relationship comes from systematic comparisons between AERONET estimations and ground-based meas. from solar databases.
the SSA increases with increasing wavelengths. According to [15], this trend is a signature of mineral dust which allows us to conclude that the SSA in those three relatively clean sites is governed by mineral dust.
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Radiative forcing and forcing efficiency
Solar RF – Monthly averages
Solar FE – Monthly averages
-36
-64
-136
-247
the presence of marine aerosols in Ersa all year round,
a smaller effect of dust outbreaks at Ersa than at Palma and
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
1 case study
MSG/SEVIRI-derived daily mean AOD at 550 nm (from http://www.icare.univ-lille1.fr/msg/browse ) illustrating the SW-NE transport pathway of African dust over the western Mediterranean
20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Context
Field campaign (10 June – 5 July 2013) in the framework of:
ChArMEx WP4 (radiative budget and climate impact)
ADRIMED (Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region)
2 supersites and 4 secondary sites
Sun-photometers
Ersa (Corsica) and Cap d’en Font (Menorca), among others
Lidars
Macinaggio (Corsica) and Cap d’en Font, among others
20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
AOD and AE
AOD440 and AE440-870
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Solar RF and FE
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Diameter
Number concentration
Meteorological balloons
Altitude [km]
Ø>6µm
Ø>6µm
MD
MD
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20 – 24 October, 2014 4th Intl. ChArMEx workshop, Trieste, Italy */18
Summary
AOD, particle size distribution, RF and FE show a clear annual cycle.
AE, coarse mode fraction, RF and FE show a SW-NE gradient.
Products such as AAOD, RRI, IRI, SSA and the asymmetry factor are subject to local sources and processes
The case study shows that those variations are highly dependent on the synoptic conditions
See also poster from Barragan et al.!
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