Chiara Levoni,
Marco Cervino,
Rodolfo Guzzi,
and Francesca Torricella
The authors are with the Istituto per lo studio delle Metodologie Geofisiche Ambientali, Consiglio Nazionale delle Ricerche, Via Piero Gobetti 101, I-40129 Bologna, Italy.
Chiara Levoni, Marco Cervino, Rodolfo Guzzi, and Francesca Torricella, "Atmospheric aerosol optical properties: a database of radiative characteristics for different components and classes," Appl. Opt. 36, 8031-8041 (1997)
A database management system has been realized that, by taking physical
and chemical properties (the complex refractive index and the size
distribution) of basic components as its starting point, allows the user to
obtain optical properties of default as well as user-defined aerosol classes.
Default classes are defined in accordance with the most widely known and used
aerosol models. We obtain user-defined classes by varying the mixing ratio of
components, creating new mixtures of default components, or by defining user
components, thereby supplying the size distribution and the refractive index.
The effect of relative humidity (RH) on the refractive index and the size
distribution is properly accounted for up to RH = 99%. The two
known mechanisms of obtaining classes from components are allowed (internal or
external mixing).
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Entries in the third and the fourth
columns refer to the publications listed at the end of this paper from which
the values of size-distribution parameters and wet-mode radii can be obtained.
The label regarding the wet-mode radius is set to n if
data are not available, while indep. means that the aerosol component is not
hygroscopic. Refractive-index types refer to chemical composition as reported
in the cited sources (last column).
The nucl and acc
are, respectively, nucleation and accumulation modes.
Values from Shettle and Fenn,2 ch are different from those applied to oceanic
and sea-salt components.
Data sources, components, and number
density mixing ratios for default classes are specified. Entries in the second
column refer to the publications listed in the references at the end of this
paper.
The nucl and acc are, respectively,
nucleation and accumulation modes.
The total number of tested cases is the
product of the number of computed aerosol optical parameters times the number
of tested wavelengths, RH levels, and aerosol classes.
Table 4
Parameters of Size Distributions and Aerosol
Abundances Employed in Fitting Measurements by Villevalde
et al.18
Mode
Parameter
WCP-112
SF
VILL
Fine
rm (μm)
0.005
0.03
0.08
σ
0.476
0.350
0.2304
Af (μm-2)
161.2
6.48
1.69
Coarse
rm (μm)
0.3
0.3
1.0
σ
0.400
0.400
0.0792
Ac (μm-2)
0.007
0.010
0.003
Table 5
Spectral Refractive Indices of the Examined Aerosol
Componentsa
Water Soluble 1
Dustlike 1
Soot
Oceanic
Wl (nm)
Real
Imaginary (×10-3)
Real
Imaginary (×10-3)
Real
Imaginary (×10-1)
Real
Imaginary
300.0
1.530
-8.00
1.530
-8.00
1.740
-4.70
1.395
-5.83 × 10-7
400.0
1.530
-5.00
1.530
-8.00
1.750
-4.60
1.385
-9.90 × 10-9
550.0
1.530
-6.00
1.530
-8.00
1.750
-4.40
1.381
-4.26 × 10-9
694.0
1.530
-7.00
1.530
-8.00
1.750
-4.30
1.376
-5.04 × 10-8
Water soluble 2 and water soluble 1 do
not differ in spectral refractive indices.
Table 6
Spectral Refractive Indices for Examined Internally
Mixed Aerosol Classes
Clean Continental
Urban
Maritime
Wl (nm)
Real
Imaginary (×10-3)
Real
Imaginary (×10-2)
Real
Imaginary (×10-4)
300.0
1.530
-8.00
1.535
-1.82
1.402
-4.01
400.0
1.530
-6.56
1.535
-1.50
1.392
-2.50
550.0
1.530
-7.04
1.535
-1.56
1.388
-3.00
694.0
1.530
-7.52
1.535
-1.63
1.384
-3.50
Table 7
Examined Aerosol-Class Input Data
Size-Distribution Parameters
Class
Component
Mixing Ratio by Volume
Mixing Ratio by Number
rm (μm)
σ
Clean continental
Water soluble 1
0.48
0.9999
0.0285
0.350
Dustlike 1
0.52
1.0 × 10-4
0.471
0.400
Urban
Water soluble 1
0.975
0.5945
0.0285
0.350
Dustlike 1
0.003
1.67 × 10-7
0.471
0.400
Soot
0.022
0.4055
0.0118
0.301
Maritime
Water soluble 2
0.05
0.99958
0.005
0.476
Oceanic
0.95
0.00042
0.3
0.400
Tables (7)
Table 1
Relevant Information on Aerosol Component Size
Distributions and Refractive Indicesa
Entries in the third and the fourth
columns refer to the publications listed at the end of this paper from which
the values of size-distribution parameters and wet-mode radii can be obtained.
The label regarding the wet-mode radius is set to n if
data are not available, while indep. means that the aerosol component is not
hygroscopic. Refractive-index types refer to chemical composition as reported
in the cited sources (last column).
The nucl and acc
are, respectively, nucleation and accumulation modes.
Values from Shettle and Fenn,2 ch are different from those applied to oceanic
and sea-salt components.
Data sources, components, and number
density mixing ratios for default classes are specified. Entries in the second
column refer to the publications listed in the references at the end of this
paper.
The nucl and acc are, respectively,
nucleation and accumulation modes.
The total number of tested cases is the
product of the number of computed aerosol optical parameters times the number
of tested wavelengths, RH levels, and aerosol classes.
Table 4
Parameters of Size Distributions and Aerosol
Abundances Employed in Fitting Measurements by Villevalde
et al.18
Mode
Parameter
WCP-112
SF
VILL
Fine
rm (μm)
0.005
0.03
0.08
σ
0.476
0.350
0.2304
Af (μm-2)
161.2
6.48
1.69
Coarse
rm (μm)
0.3
0.3
1.0
σ
0.400
0.400
0.0792
Ac (μm-2)
0.007
0.010
0.003
Table 5
Spectral Refractive Indices of the Examined Aerosol
Componentsa
Water Soluble 1
Dustlike 1
Soot
Oceanic
Wl (nm)
Real
Imaginary (×10-3)
Real
Imaginary (×10-3)
Real
Imaginary (×10-1)
Real
Imaginary
300.0
1.530
-8.00
1.530
-8.00
1.740
-4.70
1.395
-5.83 × 10-7
400.0
1.530
-5.00
1.530
-8.00
1.750
-4.60
1.385
-9.90 × 10-9
550.0
1.530
-6.00
1.530
-8.00
1.750
-4.40
1.381
-4.26 × 10-9
694.0
1.530
-7.00
1.530
-8.00
1.750
-4.30
1.376
-5.04 × 10-8
Water soluble 2 and water soluble 1 do
not differ in spectral refractive indices.
Table 6
Spectral Refractive Indices for Examined Internally
Mixed Aerosol Classes