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The Impact of Transport on the Physico -Chemical Properties of Caribbean Aerosols during RICO: African Dust and Polluti

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

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The Impact of Transport on the Physico -Chemical Properties of Caribbean Aerosols during RICO: African Dust and Polluti

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  1. 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

  2. Outline • 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

  3. To reduce the uncertainties in radiative forcing due to aerosols we need: • 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

  4. Rain In Cumulusover theOceanexperiment (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)

  5. 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?

  6. 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

  7. Sampling Locations

  8. 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

  9. DP, Antigua SFUs Sky Camera DLPI PCASP, CCN counter, SMPS, volatility system Ceilometer

  10. 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 *CSJ is supported by NOAA/ESRL since 2004, it is part of the NASA AERONET, and it is one of the GAW regional stations.

  11. CSJ, Puerto Rico

  12. 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

  13. East Peak, Puerto Rico View looking upwind to CSJ, pointed to by the arrow. Darrel Baumgardner (UNAM) and Stephan Borrmann (MPIC) Cloud water collector 2D-C and 2D-P Trailer

  14. 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

  15. (1) Origin of the Air Masses

  16. Clean Air Masses

  17. African Dust

  18. Anthropogenic Pollution from North America

  19. Air Masses Origin: Dian Point (DP)January 2006 http://www.arl.noaa.gov/ready.html

  20. Air Masses Origin: Cape San Juan (CSJ) January 2006 http://www.arl.noaa.gov/ready.html

  21. (2) Aerosol Physical Properties

  22. PCASP - Mean Particle Size Distribution - DP Enhancement 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

  23. SMPS + PCASP - Particle Size Distribution - Clean Air Jan 19-20 SMPS = Scanning Mobility Particle Sizer

  24. SMPS + PCASP - Particle Size Distribution - African Dust Jan 14-16 Enhancement in the accumulation and coarse modes.

  25. 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.

  26. CCN Spectra 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.

  27. DLPI Size-Resolved Mass Concentrations: Clean vs African Dust – Dian Point

  28. 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.

  29. (3) Aerosol Chemical Composition and the Contribution of Particulate Organic Matter)

  30. TC Concentrations in Front and Back Quartz Filters (Positive Artifact) 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

  31. TC and EC after Correction for the Positive Artifact Uncorrected concentrations were on average 50 and 260 ngm-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.

  32. ASASP-X: Particle Size Distribution-Volatility Spectra: African Dust • Small decrease in particle number due to the lossof SO42-. • Little contribution by OC aerosol. • Volatilization of NaCl. • Significant amount of residual refractory material (silicates, soot,..). SVOC = semivolatile OC AMS = (NH4)2SO4

  33. Average Particle Size Distribution-Volatility Spectra Anthropogenic Pollution from NA • 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

  34. Size-Resolved Mass Concentrations of Ca2+ and Mg2+: Clean vs African Dust African Dust Clean

  35. 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% Marine Aerosol (Warneck, 1988) Cl/Na = 1.590 SO4/Na = 0.885 Ca/Na = 0.058 nss-sulfate in remote/clean areas is about 200 ng m-3. Date: Jan 5-7, 2005 POM = particulate organic matter (OC’ * 1.8)

  36. 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% Marine Aerosol (Warneck, 1988) Cl/Na = 1.590 SO4/Na = 0.885 Ca/Na = 0.058 nss-sulfate in remote/clean areas is about 200 ng m-3. Date: Jan 11-14, 2005

  37. 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 POM Na+ NH4+ SO4= Cl- Marine Aerosol (Warneck, 1988) Cl/Na = 1.590 SO4/Na = 0.885 Ca/Na = 0.058 nss-sulfate in remote/clean areas is about 200 ng m-3. NO3- Date: Jan 21-24, 2005

  38. Fraction of Particulate Organic Matter (POM) NSSM = non-sea-salt aerosol mass = [mass – (Na+ + Cl-)]

  39. 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.

  40. 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

  41. Thanks for listening!

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