**Table 4: Intensive aerosol properties derived
from CMDL network**

å | The Angstrom exponent, defined by the power-law s_{sp}
proportional to l^{-å}, describes the
wavelength-dependence of scattered light. In the figures below, a
is calculated from measurements at 550 and 500 nm wavelengths. Situations
where the scattering is dominated by submicrometer particles typically have
values around 2, while values close to 0 occur when the scattering is dominated
by particles larger than a few microns in diameter. |

w_{o} |
The aerosol single-scattering albedo, defined as s_{sp}/(s_{ap}
+ s_{sp}), describes the relative contributions
of scattering and absorption to the total light extinction. Strongly
absorbing aerosols (e.g., elemental carbon) have values around 0.3. |

g, b | Radiative transfer models commonly require one of two integral
properties of the angular distribution of scattered light (phase
function): the asymmetry factor g or the hemispheric backscatter fraction
b. The asymmetry factor is the cosine-weighted average of the phase function,
ranging from a value of -1 for entirely backscattered light to +1 for entirely
forward-scattered light. The hemispheric backscatter fraction b is s_{bsp}/s_{sp}. |

a_{i} |
The mass scattering efficiency for species i, defined
as the slope of the linear regression line relating ssp
and the mass concentration of the chemical species, is used in chemical
transport models to evaluate the radiative effects of each chemical species
prognosed by the model. This parameter has typical units of m^{2}g^{-1}. |