A.D. Clarke, V.N. Kapustin

School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, USA

AEROSOL SIZE DISTRIBUTIONS, PROPERTIES AND VERTICAL PROFILES OVER THE PACIFIC: TOWARDS AN AEROSOL CLIMATOLOGY

TOWARDS AN AEROSOL CLIMATOLOGY:Its all about LAYERS , baby!!!

A.D. Clarke, K.G.Moore, V.N. Kapustin

School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, USA

REGIONAL AEROSOL AND LONG RANGE TRANSPORT OVER THE PACIFIC

FOCUS

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

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

PROJECTTimeYear #Flights #Profiles GLOBE_111/07-11/3019891848GLOBE_205/01-06/0519901537ACE_110/31-11/2219953396PEMT_A08/24-09/2619962154PEMT_B03/04-04/1019991935INDOEX02/04-03/0819991738

WE HAVE OBSERVED

In regions free of continental influence the marine boundary layer (MBL) aerosol mass and optical properties are dominated by sea-salt (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 2km often creates structured rivers of aerosol (dust, pollution) that is advected over global scales before re-entrainment into the surface boundary layer.

(CONT.)

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.SpinhirneGSFC

Structure of Aerosol Plumes over Oceans India Pollution (INDOEX)

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

CONCLUSIONS

The evaporating regions of ITCZ cloud outflow layers [4 to >12km] 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 near-cloud 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.

INDOEX99Pollution haze reducing cloud reflectivity

PEMT-BCumulus layers (photo), vertical profile of nuclei layers and nucleation from sulfuric acid at cloud edges

PEMT-B Flight 17 Vertical profiles of aerosol number concentration, light scattering and size distributions

PEMT-B Flight 18 Vertical profiles of SO2, aerosol number concentration, light scattering, absorbtion and size distributions

PEMT-B Flights 17 & 18 Vertical profiles of SO2, aerosol number concentration, light scattering, absorbtion and size distributions