an annual cycle of size-resolved aerosol hygroscopicity at a forested site in colorado ezra levin...
DESCRIPTION
[Levin et al, 2009; Schichtel et al, 2008] Regional aerosol 21% 45% Modern C Fossil C We expect biogenic organics to be important, especially in the summerTRANSCRIPT
An annual cycle of size-resolved aerosol
hygroscopicity at a forested site in Colorado
Ezra LevinA.J. Prenni, S.M. Kreidenweis, M.D.
Petters, R.C. Sullivan, S.A. Atwood, J. Ortega, P.J. DeMott and J.N. Smith
Funded by: NSF (ATM-0919042)
AMS Annual Meeting 1/24/12
(Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen)
BEACHON
What are the impacts of biogenic emissions on aerosol hygroscopicity and CCN concentrations?
[Levin et al, 2009; Schichtel et al, 2008]
Regional aerosol
21% 45%
Modern C
Fossil C
We expect biogenic organics to be important, especially in the summer
Size resolved cloud condensation nuclei
Total NCCN
Dc
Hygroscopicity parameter: kappa
DRTM
DDDDDS
w
Was
d
d
/
33
33 4exp1
)(
κ = 0.1
κ = 0.6
[Petters and Kreidenweis, 2007]
SOA
Ammonium Sulfate
0.13 ± 0.04
0.14 ± 0.05
0.15 ± 0.05
0.17 ± 0.06
0.22 ± 0.12
48 ± 3
54 ± 5
66 ± 2
85 ± 3
147 ± 14
KappaActivation Diameter
Kappa timeline
Low kappa indicates large organic component
Kappa and CCN have a seasonal cycle
Why do kappa and CCN change with season and size?
Largest particles are more variable.
Smallest particles consistently low.
New particle formation
New particle formation
At larger diameters, New particles have lower hygroscopicity.
New particle formation
NPF affects aerosol hygroscopicity and CCN concentration.
SOA
Conclusions
The aerosol in Manitou Forest is highly organic dominated.
New particle formation appears to depress kappa but increase CCN.
It is likely that the new CCN have a large biogenic organic component, thus linking the biosphere, hydrosphere and atmosphere.