ATMO/OPTI 656b
Spring 2009
Scattering plane
z is the direction of the incident light propagation (p.61)
x-polarized light (BH p. 101)
recreate BH figures using matlab
What do we need for the solution
Scattering and absorption by the particle
Need the far field solution of the scattered wave
Need the solution for the internal wave as this is relevant to absorption by the particle
The scattered wave and internal wave solutions are written in term of the superposition of normal
modes of EM fields generated by the spherical particle
xQ
(4.61)
xQ
(4.62)
and Qabs follows from (3.25). All infinite series can be truncated after nmax terms. For
this number Bohren and Huffman (1983) proposed the value
24
3/1
++= xxn
(p.477)
and this value is used here as well.
max
Need the angular dependence
Forward scattering
Single versus multiple scattering
Radar backscatter r6.
Rainfall rate r4.
S-pol radar
Extinction paradox
Absorption dominates over scattering for sufficiently small absorbing particles
effect of same aerosol at visible and IR wavelengths
(as particle size become much smaller than wavelength, absorption dominates)
index of refraction depends on wavelength
1
ERK 4/28/09
ATMO/OPTI 656b
Spring 2009
when we see light scattered from a cloud, approximately how many times has that light
scattered?
2
ERK 4/28/09