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Transcript of The Impact of Transport on the Physico-Chemical Properties of Caribbean Aerosols during RICO:...
The Impact of Transport on the Physico-Chemical
Properties of Caribbean Aerosols during RICO: African
Dust and Pollution from North America
Olga L. Mayol-Bracero Institute for Tropical Ecosystem Studies
University of Puerto Rico, Río Piedras Campus
AFRICAN DUST WORKSHOP NASA & HU – UPR-M, Parguera, Lajas
21.June.2011
Introduction Objectives Experimental
• Sampling Locations• Measurements and Analyses
Results• Origin of the Air Masses• Aerosol Physical Properties • Chemical Composition and the Contribution of
Particulate Organic Matter Summary Acknowledgments
Outline
a better knowledge of the physical, chemical, and radiative properties of fine aerosols (especially of organics and mineral dust) and clouds.
a better understanding of the effects of aerosols on clouds and their interactions.
measurements in a globally representative range of natural/background and anthropogenically perturbed environments (background conditions, the Caribbean… PR!!!).
studies in the tropics• occupy ca. 50% of the surface of the globe• most photochemically active region of the atmosphere (highest
OH concentrations worldwide)• contribute significantly to the budget of gases and aerosols within
the Earth’s atmosphere• driving force for the Earth’s atmosphere circulation
To reduce the uncertainties in radiative forcing due to aerosols we need:
Rain In Cumulus over the Ocean experiment (RICO) - www.joss.ucar.edu/rico/
The RICO core objective was to characterize and understand the properties of trade wind cumulus clouds, with particular emphasis on determining the importance of precipitation.
Location: Caribbean - Antigua, Barbuda, and Puerto Rico 3 aircrafts (NCAR C-130, UK BAe-146, UW King Air), 1
research vessel (NSF Seward Johnson), and 4 ground-based stations (2 in Puerto Rico, 1 in Antigua, and 1 in Barbuda)
Sampling Period: November 2004 to January 2005 PRACS (2004) and PRADACS (2010 – 2012)
Two Fundamental RICO Questions: What is the spatial and temporal variability of
aerosol chemical and physical properties in the trade wind environment?
How do aerosols impact the microphysics of trade wind cumuli?
Aerosol Ground-Based Stations: Objectives
To determine the:
origin of the air masses sampled
physical and chemical properties of the atmospheric particles sampled:
• size, cloud condensation nuclei (CCN), mass concentration, and chemical composition
contribution of particulate organic matter (POM) to the total aerosol mass
BBaarrbbuuddaa
AAnnttiigguuaa
Caribbean Sea
Atlantic Ocean
Sampling Locations
Instrumentation: Dian Point (DP), Antigua (17.03 N, 61.48 W)
UPR-RP DLPI SFUs Weather Station
Meteo-France Condensation particle
counter (CPC) CCN counter SMPS
University of Leeds, UK Volatility system PCASP-X
Arizona State University Filter system (surface
analysis) University of Warsaw
and Scripps Institute Vaisala ceilometer Whole sky camera
Antigua
PCASP, CCN counter, SMPS, volatility system
DLPI
SFUs
Ceilometer
Sky Camer
a
DP, Antigua
Instrumentation: Cape San Juan (CSJ), Puerto Rico (18' 15 N, 66' 30 W)
UPR-RP DLPI MOUDI SFUs High-volume sampler Aethalometer Nephelometer Condensation particle
counter Weather Station
UNAM, Mexico OPC PMS LasAir
Max Planck Institute for Chemistry, Mainz, Germany
CCN counters (2) SMPS
University of Manchester, UK
Aerosol mass spectrometer
HTDMA Condensation particle
counter
University
East Peak1000 m
CSJ
S-Band weather radar
Puerto Rico
*CSJ is supported by NOAA/ESRL since 2004, it is part of the NASA AERONET, and it is one of the GAW regional stations.
CSJ, Puerto Rico
Instrumentation: East Peak, Puerto Rico (18o 16' N, 65o 45' W, 1051 m asl)
UPR-RP MOUDIs SFUs Cloud collector
UNAM, Mexico OPC PMS LasAir II Condensation particle
counter CCN counter FSSP-100, 2D-C, 2D-P Nephelometer Rain water collector Weather Station
Institute of Tropospheric Research, Leipzig, Germany
Condensation particle counter
PSAP
Max Planck Institute for Chemistry, Mainz, Germany
Aerosol mass spectrometer
East Peak, Puerto Rico
Cloud water collector
Darrel Baumgardner (UNAM) and Stephan Borrmann (MPIC)
Trailer
View looking upwind to CSJ, pointed to by the arrow.
2D-C and 2D-P
Online Measurements: Condensation particle counter Cloud condensation nuclei
counter PCASP, SMPS ASASP-X Volatility system
Analyses: Ion Chromatography (Na+, NH4
+, Ca2+, K+, Mg2+, Cl-, NO3
- SO42-,
acetate, formate, oxalate, and MSA)
Thermal/optical analysis (Total Carbon (TC), organic carbon (OC), and elemental carbon (EC).
Samplers: Aerosols – Stacked-filter units
and Dekati low-pressure impactor
Meteorological data
Daily Aerosol Optical Thickness Satellite Images from NOAA’s AVHRR / NESDIS
Air Mass Backward Trajectories NOAA ARL HYSPLIT model
(HYbrid Single-Particle Lagrangian Integrated Trajectory)
Measurements and Analyses
(1) Origin of the Air Masses
Clean Air Masses
African Dust
Anthropogenic Pollution from North America
http://www.arl.noaa.gov/ready.html
Air Masses Origin: Dian Point (DP) January 2006
http://www.arl.noaa.gov/ready.html
Air Masses Origin: Cape San Juan (CSJ)January 2006
(2) Aerosol Physical Properties
PCASP - Mean Particle Size Distribution - DPEnhancement due to anthropogenic pollution - Jan 20-21 (black line).
Enhancement in the accumulation and coarse modes, most likely due to dust particles - Jan 14-16 (blue line).
PCASP = Passive Cavity Aerosol Spectrometer Probe
SMPS + PCASP - Particle Size Distribution - Clean Air
Jan 19-20
SMPS = Scanning Mobility Particle Sizer
SMPS + PCASP - Particle Size Distribution - African Dust
Jan 14-16
Enhancement in the accumulation and coarse modes.
SMPS + PCASP - Particle Size Distribution Anthropogenic Pollution from North America
Jan 20-21
Significant enhancement in the accumulation mode (0.2-0.4 mm), some enhancement also in the coarse mode.
Aged pollution (North America and African Dust) changes size distributions in the accumulation and coarse modes, therefore, affecting also the CCN concentrations.
CCN Spectra
0
50
100
150
200
250
300
350
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Supersaturation, %
CC
N c
on
cen
tra
tion
, cm
-3
Clean
African Dust
Pollution North America (USA)
The increase in the coarse mode particles (African dust and NA pollution) seen before can also lead to higher concentrations of so-called giant CCN, and these can have an impact on precipitation formation, and thus affect the precipitation efficiency and cloud life-time.
DLPI Size-Resolved Mass Concentrations: Clean vs African Dust – Dian Point
0
5
10
15
20
25
30
0.01 0.1 1 10 100
Diameter, mm
dM
/dlo
gD
p, m g
m-3
Clean
African Dust
Filter Sampling – Mass Concentrations – Fine Fraction
Average total mass concentrations (Dp < 2 mm) are 1.4 mg m-3 for DP and 1.9 mg m-3 for CSJ, typical of remote marine areas. The highest concentrations were at CSJ and during the dust period. On average fine mass concentrations were ~1.6 mg m-3.
0
500
1000
1500
2000
2500
3000
3500
Clean African Dust Antropogenic Pollution
aver
age
mas
s co
ncen
trat
ion,
ng
m -3
Dian Point
CSJ
(3) Aerosol Chemical Composition and the
Contribution of Particulate Organic Matter)
TC Concentrations in Front and Back Quartz Filters (Positive Artifact)
0
50
100
150
200
250
300
350
400
Clean African Dust Antropogenic Pollution
TC
mas
s co
ncen
trat
ions
, ng
m -3
FQ-DP BQ-DPFQ-CSJ BQ-CSJ
The % of the positive artifact was on average 57%; therefore, not correcting for this will contribute to a significant overestimation of TC concentrations.
Positive artifact - adsorption of organic vapors on the quartz filters
TC and EC after Correction for the Positive Artifact
Uncorrected concentrations were on average 50 and 260 ng m-3 for the DP and CSJ, respectively. Corrected concentrations were 18 ng m-3 (DP) and 118 ng m-3 (CSJ). EC concentrations were at low-to-non detectable levels.
0
50
100
150
200
Clean African Dust Antropogenic Pollution
mas
s co
ncen
trat
ions
, n
g m
-3
TC-DP
EC-DP
TC-CSJ
EC-CSJ
ASASP-X: Particle Size Distribution-Volatility Spectra: African Dust
150˚C / SVOC 570˚C / OC
730˚C / NaCl270˚C / AMS
SVOC = semivolatile OC AMS = (NH4)2SO4
Small decrease in particle number due to the loss of SO4
2-. Little contribution by OC aerosol. Volatilization of NaCl. Significant amount of residual
refractory material (silicates, soot,..).
Average Particle Size Distribution-Volatility Spectra Anthropogenic Pollution from NA
150˚C / SVOC 570˚C / OC
730˚C / NaCl270˚C / AMS
• Significant loss of SO42- particles.
• Evidence of OC particles, due to a slight reduction in particle number from 270°C to 570°C.
• At 730°C, almost all particles >0.3 mm are volatilized.
SVOC = semivolatile OC AMS = (NH4)2SO4
Size-Resolved Mass Concentrations of Ca2+ and Mg2+: Clean vs African Dust
0
100
200
300
400
500
600
0.01 0.1 1 10 100
Diameter, mm
dM
/dlo
gD
p,
ng
m-3
Mg++ Clean Ca++ Clean Mg++ African Dust Ca++ African Dust
African Dust
Clean
Chemical Composition – Fine FractionClean Air, Dian Point
Cl/Na = 1.45 SO4/Na = 0.77 Ca/Na = 0.077 EC was not detected. nss-sulfate = 74 ng m-3
residual mass = 40%
Date: Jan 5-7, 2005
POM = particulate organic matter (OC’ * 1.8)
Marine Aerosol (Warneck, 1988)Cl/Na = 1.590SO4/Na = 0.885
Ca/Na = 0.058
nss-sulfate in remote/clean areas is about 200 ng m-3.
24.0%
2.9%
1.4%
3.0%
1.8%
0.4%
0.1%
0.0%34.7%
3.1%
0.3%
18.3%
8.8%
0.6%
0.5%0.0% Na+
NH4+ K+ Mg++ Ca++ AcetateFormateNO2- Cl- NO3- MalonateSO4= Oxalate MSAEC POM
Na+
Cl-
SO4=
POM
Chemical Composition – Fine Fraction African Dust, Dian Point
Cl/Na = 1.63 SO4/Na = 0.70 Ca/Na = 0.17 EC was detected. nss-sulfate = 128 ng m-3
higher Ca2+, lower POM residual mass = 62%
Date: Jan 11-14, 2005
24.8%
1.4%
1.7%
3.2%
4.1%
0.2%
0.1%
0.0%40.5%
3.6%
0.1%
17.5%
0.5% 0.3% 1.0%1.0% Na+
NH4+ K+ Mg++ Ca++ AcetateFormateNO2- Cl- NO3- MalonateSO4= Oxalate MSAEC POM
SO4=
Cl- Ca2+
Na+
Marine Aerosol (Warneck, 1988)Cl/Na = 1.590SO4/Na = 0.885
Ca/Na = 0.058
nss-sulfate in remote/clean areas is about 200 ng m-3.
Chemical Composition – Fine Fraction Anthropogenic Pollution from North America,
Dian Point
Cl/Na = 1.11 (sea-spray acidification)
SO4/Na = 2.03 Ca/Na = 0.08 nss-sulfate = 193 ng m-3
Date: Jan 21-24, 2005
18.4%
6.5%
1.1%
2.3%
1.5%
0.4%
0.1%
0.0%20.5%
4.5%
0.3%
37.5%
1.4%0.9%
0.0%4.6%
Na+ NH4+ K+ Mg++ Ca++ AcetateFormateNO2- Cl- NO3- MalonateSO4= Oxalate MSAEC POM
Na+
NH4+
Cl-
NO3-
SO4=
POM
Marine Aerosol (Warneck, 1988)Cl/Na = 1.590SO4/Na = 0.885
Ca/Na = 0.058
nss-sulfate in remote/clean areas is about 200 ng m-3.
Fraction of Particulate Organic Matter (POM)
NSSM = non-sea-salt aerosol mass = [mass – (Na+ + Cl-)]
Summary
Aged pollution from African Dust and from North America: increases the number of particles in the accumulation and coarse modes causes higher CCN concentrations the increase in the coarse mode could lead to higher concentrations of the so-
called giant CCN, having an impact on precipitation formation, and thus cloud life-time.
The positive artifact in carbonaceous samples is significant (~50%). The predominant aerosol species in all cases (Dp < 2 mm) were Cl-, Na+, and
SO4=. SO4
= was in higher concentrations during the polluted case. POM is representing a fraction of the total mass that can go from ~ 1 to ~ 40%
(average: 10 ± 16 %) (avg POM = ~115 ng m-3). POM/NSSM from 1 to 70%. Most significant amounts of organic matter are seen during pollution events;
nevertheless, based on the concentrations of species such as EC, OC, and nss- SO4
=, the anthropogenic activity during the sampling periods was very low. Pollution from North America: increase in SO4
=, NH4+, NO3
-, and POM; sea-spray acidification; highest concentrations of nss- SO4
=; and partially reacted sea-salt particles.
Based on the concentrations of species such as EC, OC, and nss- SO4=, in
general, the anthropogenic activity at both sampling sites was very low.
Acknowledgements F. Morales, G. Santos – UPR ITES RICO-PRACS participants (M. Repollet, A. Kasper-Giebl, H. Puxbaum, L.
Gomes, J.D. Allan, J.J.N. Lingard, J.B. McQuaid, D. Baumgardner, G. B. Raga, A. Kasper-Giebl, H. Puxbaum, L. Gomes, G.P. Frank, U. Dusek, M.O. Andreae, S. Borrmann, J. Schneider, S. Mertes, S. Walter, M. Gysel, M. Krämer, D. Baumgardner, G. B. Raga, F. García-García)
T. Novakov, T. W. Kirchstetter – Lawrence Berkeley National Lab. J. A. Ogren, P. Sheridan, E. Andrews – NOAA ESRL S. Decesari - Institute of Atmospheric Science and Climate-C.N.R.,
Bologna, Italy R. J. Morales-De Jesús - Physical Sciences Department, UPR-RP R. Rauber - University of Illinois Conservation Trust of Puerto Rico, Cabezas de San Juan El Yunque National Forest, PR Government of Antigua and Barbuda, special thanks to Ms. M. Mikael,
Steven, and Mr. Errol – FBO! NSF – Physical and Dynamic Meteorology and Atmospheric Chemistry
Thanks for listening!