\begin{table}%t1
%\centering
\par
\caption{Definitions of variables.\label{T1}}
  \begin{tabular}[]{cl}
 \hline\hline
 $A_{\rm V}$  &   Ring particle bolometric Bond albedo \\
 $A_{\rm S}$  &   Saturn bolometric Bond albedo =0.342\\
$B$  &   Earth elevation above the ring plane\\
 $B'$  &  Solar elevation above the ring plane\\
 $C_{\rm H}$ & Specific heat (\uheatc) \\
$C(B'$,~$\tau $) & Particle fractional lit area \\
$C(B$,~$\tau $) & Particle fractional visible area \\
$D_{\rm AU}$ & Sun-Saturn distance in astronomical units \\
$\epsilon_{\rm ir}$ & Infrared emissivity of ring particles, $\epsilon_{\rm ir}=1$ \\
$F_1$ & Direct sunlight \\
$F_2$ & Sunlight reflected by Saturn \\
$F_3$ & Thermal radiation from Saturn \\
$F_4$ & Sunlight scattered by nearby particles \\
$\Gamma$ & Thermal inertia (\uthi) \\
$K$ & Thermal conductivity (\uthc)\\
$\mu$ & sin(B)\\
$\Omega_{\rm P}$ & Solid angle of the lit planet hemisphere\\
$\Omega^{'}_{\rm P}$ & Solid angle of the planet hemisphere\\
$\Omega_R$ & Solid angle subtended by all nearby particles\\
$p$ & Porosity of the particle regolith\\
$z$ & Depth in particle \\
$\rho_0, \rho$ & Volume density of the regolith ($\rho_0=918$ ${\rm kg~m^{-3}}$) \\
$S,~\sigma $ & Solar constant =1370 ${\rm W~m^{-2}}$, Stefan constant \\
$\tau $ & Ring optical depth \\
$T_{\rm B}$ & Ring brightness temperature\\
$T_{\rm S}$ & Particle surface temperature\\
$T_{\rm P}$ & Saturn planet effective temperature, $T_{\rm P}=95$~K \\
$\omega$ & Particle mean motion\\
\hline
\end{tabular}
\end{table}