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. Author manuscript; available in PMC: 2020 Dec 2.
Published in final edited form as: Atmos Chem Phys. 2019 Jul 8;19(13):8591–8617. doi: 10.5194/acp-19-8591-2019

Table 1.

Hygroscopicity parameters used by the participating models for water uptake calculations.

Model SO4 OA SS DU BC NO3
CAM5-Chem-APM 0.9 0.1 1.28 0 0 0.9
CAM5-Chem-ATRAS2 0.61 0.1 1.16 0.001 1 × 10−6 0.61
CAM5_MAM3 0.507 0.1 1.16 0.068 0 N/A
CAM5_MAM4 0.507 0 1.16 0.068 N/A
CAM5.3-Oslo 0.507(1) 0.14 1.2 0.069 5 × 10−7 N/A
ECHAM5.5-HAM2-ELVOC_UH 0.6 0.06 1.12 0
ECHAM6-HAM2(2) 0.7 0 1.3 0 0 N/A
ECHAM6-HAM2-AP(2) 0.7 0 1.3 0 0 N/A
EMAC(3) 0.1 1.12 0 0 N/A
GEOS-Chem-APM 0.9 0.1 1.28 0 0 0.9
GEOS-Chem-TOMAS 1.0 0.1(4) 1.2 0.01 0 N/A
GISS-E2.1-MATRIX 0.507 0.141 1.335 0.14 5 × 10−7 0.507
GISS-E2-TOMAS 0.7 0.15(5) 1.3 0 0 N/A
TM4-ECPL 0.6 0.1 1.0 0 0 N/A
TM5 0.6 0.1 1.0(6) 0 0 0.6
1

In CAM5.3-Oslo the hygroscopicity parameters κ for pure ammonium sulfate or sulfuric acid are 0.507 and 0.534, respectively. For internal mixtures, κ is a mass-weighted average of the aerosol components, except for particles coated (> 2 nm) with SO4, OA and/or SS, where κ is a mass-weighted average of the components of the coating (Kirkevåg et al., 2018).

2

ECHAM6-HAM2 and ECHAM6-HAM2-AP use the Abdul-Razzak and Ghan (AR-G) activation scheme (Abdul Razzak and Ghan, 2000). The reported values are approximated using the number of ions and osmotic coefficients used in the AR-G scheme.

(3)

EMAC model simulates the effective hygroscopicity parameter κ of each aerosol size mode in order to describe the influence of chemical composition on the CCN activity of aerosol particles (Pringle et al., 2010). These values are the internally mixed κ calculated across the nucleation, Aitken, accumulation and coarse modes. The effective aerosol hygroscopicity parameter κ is calculated according to the simple mixing rule proposed by Petters and Kreideweis (2007) using the volume fraction and hygroscopicity parameter of each chemical component (23 salts from ISORROPIA-II and 4 bulk species) taken from Petters et al. (2007) and Sullivan et al. (2009)

(4)

for hydrophilic OA κ = 0.1, for hydrophobic OA κ = 0.01 and

(5)

for hydrophilic ORG (Lee et al., 2015). For hydrophobic, κ = 0.

(6)

for NaCl κ = 1, for Na2SO4 κ = 0.95. N/A: not considered in this study.