AEROSOL SIZE DISTRIBUTIONS PROPERTIES AND VERTICAL PROFILES OVER

AEROSOL SIZE DISTRIBUTIONS, PROPERTIES AND VERTICAL PROFILES OVER THE PACIFIC: TOWARDS AN AEROSOL CLIMATOLOGY A. D. Clarke, V. N. Kapustin School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, USA

TOWARDS AN AEROSOL CLIMATOLOGY: It’s all about LAYERS , baby!!!

REGIONAL AEROSOL AND LONG RANGE TRANSPORT OVER THE PACIFIC A. D. Clarke, K. G. Moore, V. N. Kapustin School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, USA

FOCUS l Contribute to the understanding of the climatology and variability of aerosol over the remote oceans (Pacific) and the processes that establish its characteristics (size, concentration, chemistry, optical properties)

STUDY REGIONS l Various research programs have explored the aerosol fields in the Central Pacific remote marine boundary layer (MBL) and free troposphere (FT) - PEM-Tropics A&B, ACE -1, GLOBE 1&2, CPACE, SAGA 1, 2&3, RITS 88, 93&94. . .

EXPERIMENTS AND LOCATIONS PROJECT GLOBE_1 GLOBE_2 ACE_1 PEMT_A PEMT_B 35 INDOEX Time Year #Flights #Profiles 11/07 -11/30 1989 18 48 05/01 -06/05 1990 15 37 10/31 -11/22 1995 33 96 08/24 -09/26 1996 21 54 03/04 -04/10 1999 19 02/04 -03/08 1999 17 38

WE HAVE OBSERVED l l l In regions free of continental influence the marine boundary layer (MBL) aerosol mass and optical properties are dominated by seasalt (e. g. ACE-1 Tasmania ) with some natural sulfate. Continental aerosol can influence or dominate (MBL) aerosol and optical properties over extensive regions until depleted by removal processes in MBL. Lofting of continental aerosol above 2 km often creates structured rivers of aerosol (dust, pollution) that is advected over global scales before re-entrainment into the surface boundary layer.

(CONT. ) l l l Deep convection and precipitation removes MBL aerosol mass and number and vents cleaned surface air aloft. Can provide favorable region for natural nucleation with enhanced “new” aerosol number but with little mass. Cloud venting aloft and larger scale subsidence and entrainment will couple free troposphere (FT) aerosol and MBL aerosol cycles including their evolution and properties. Column aerosol properties (satellite) will reflect the above processes and a mix of natural and anthropogenically influenced aerosol. In general – surface based in-situ measurements will provide uncertain assessments of column aerosol properties.

Aerosol Size Distributions - Basics and Interpretation

Size Distributions and Volatility as a Tool to Study Particles Composition

Size Distributions and Volatility as a Tool to Study Particles Composition (cont. )

RCN Ratio - an Indicator of Clean vs. Polluted Air Aloft J. Spinhirne GSFC

Structure of Aerosol Plumes over Oceans India Pollution (INDOEX)

Structure of Aerosol Plumes over Pacific African Biomass Burning (PEMT-A) NASA PEMT-A E. Browell

CONCLUSIONS l l l The evaporating regions of ITCZ cloud outflow layers [4 to >12 km] are sources of new particles (nucleation) that could populate extensive regions of the tropical free troposphere. Nucleation is linked to elevated sulfuric acid derived from oceanic DMS for these nearcloud environments and appeared consistent with classical binary nucleation theory. Particle concentrations often decreased from aloft toward the surface in this region. This, and no observed near-surface nucleation, suggests that boundary layer concentrations are sustained against precipitation removal through subsidence and entrainment of "new" particles formed aloft.