It is an exponent that expresses the spectral
dependence of aerosol optical thickness (τ) with the wavelength of
incident light (λ).
The spectral dependence of aerosol optical thickness can be
approximated (depending on size distribution) by,
τ
a = β λ
α
where α is Angstrom exponent (β = aerosol
optical thickness at 1 μm)
Angstrom exponent (computed from τ measurements on two different
wavelengths) can be used to find τ on another wavelength using the
relation.
The Angstrom exponent provides additional information on the particle
size(larger the exponent, the smaller the particle size), aerosol
phase function and the relative magnitude of aerosol radiances at
different wavelengths.
Atmos Composition
