Extinction Optical Depth

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Extinction Optical Depth

As mentioned above, the optical efficiencies are the ratios between geometric cross sectional area of the particle and the particle's efficiency at attenuating light. Thus the optical depths $\tauxxx$ , per particle, are

$\begin{subequations} \begin{align} \tauabs(\rds,\wvl) & = \pi \rds^2 \fshabs(\rd... ...auext(\rds,\wvl) & = \pi \rds^2 \fshext(\rds,\wvl) \end{align}\end{subequations}$

The relationship between the optical depths is exactly analogous to the relationship between the optical efficiencies (102), so that

$\begin{displaymath}\tauext(\rds,\wvl) = \tauabs(\rds,\wvl) + \tausct(\rds,\wvl) \end{displaymath}$

(101)

Using (18) we see that a column of depth $\hgtdlt$ m with a homogeneous particle concentration of $\cncfnc(\rds)$ produces optical depths of

$\begin{subequations} \begin{align} \tauabs(\cncfnc(\rds),\wvl) & = \pi \rds^2 \f... ...pi \rds^2 \fshext(\rds,\wvl) \cncfnc(\rds) \hgtdlt \end{align}\end{subequations}$

Charlie Zender
2000-07-14