\begin{table}  %T3 
      \caption{ \label{SimParamSens}Sensitivity of $\psi$ to a 1\% perturbation
in some simulation parameters under standard conditions.}
   
         \begin{tabular}{llll}
            \hline\hline
            \noalign{\smallskip}
            Name of perturbed variable  &  {\rm Symbol}  & $\psi$~{\rm change\ (\%)} \\
             \hline
           Mesospheric laser irradiance        & $I$		& \ \ ~ 0.025	\\
Geomagnetic field in mesosphere     & $B$		& -0.33 \\
Average mesospheric temperature     & $T_{\rm Na}$	& -0.48 \\
Beam atom exchange rate			  & $\gamma_{\rm ex}$ 	& \ \ ~ 0.0025 \\
Weighted v.c.c.\tablefootmark{\ast} rate 				& $\gamma_{{\rm vcc}}$ & \ \ ~ 0.15 \\
Weighted spin-exchange rate at $T_{\rm Na}$	& $\gamma_S$	& \ \ ~ 0.013 \\
Recoil frequency (50~kHz)		& 		& -0.24	\\
            \hline
         \end{tabular} 
\tablefoot{
\tablefoottext{\ast}{v.c.c. = velocity-changing collision.}}
   \end{table}