\begin{table}
\caption{\label{tab1}The observed and best-fitting parameters of the 2001
October 31 discontinuity event.}
%\centerline
{
\par
\begin{tabular}{lcccc}
\hline\hline
\multicolumn{1}{c}{Parameter}&~~~~Observed values$^{a}$&~~~~& Best-fit values\\
\hline
$\vec{B}_{1}(nT)$ &~~~~~~~~~~~(--3.65, --0.12, --1.09) &~~~~& (--3.91, --0.17, --1.57) \\
$\vec{B}_{2}    $ &~~~~~~~~~~(--4.58, 3.73, 0.40)  &~~~~& (--4.48, 3.30 0.67)  \\
$N_{1},N_{2} ({\rm cm}^{-3})$ &~~~~~~~~~~ 3.55, 10.24        &~~~~~&   3.75, 10.04       \\
$\vec{V}_{1}    $ &~~~~~~~~~~(--340.8, 25.7, 2.1)  &~~~~& (--343.9, 23.9, 4.4)  \\
$\vec{V}_{2}    $ &~~~~~~~~~~(--396.5, --4.1, --24.0)  &~~~~& (--393.4, --2.3, --26.3)  \\
$\beta_{1},\beta_{2}$ &~~~~~~~~~~0.657, 2.852  &~~~~&  0.551, 2.709\\
$\vec{n}$     &~~~~~~~~~~(--0.943, --0.107, --0.316) &~~~~&  (--0.947,    0.050,    --0.316) \\
$\vec{s}$     &~~~~~~~~~~(--0.222,  0.909, 0.352) &~~~~&  (--0.135,  0.833,  0.537) \\
$\vec{t}$     &~~~~~~~~~~( 0.250, 0.402, --0.881) &~~~~&  ( 0.290, 0.551, --0.782) \\
$M_{\rm AN1},M_{\rm AN2}$ &~~~~~~~~~~1.836, 1.080       &~~~~&     1.518, 0.928 \\
$M_{\rm F1},M_{\rm F2}$ &~~~~~~~~~~ 1.829, 0.514      &~~~~&   1.509, 0.529       \\
$\theta_{\rm BN1}$ &~~~~~~~~~~$4.82^{\circ}$   &~~~~& $6.26^{\circ}$   \\
\hline
\end{tabular}}
\medskip
\par
$^{a}$ The SD of $\vec{B}_{1}$ is (0.30, 0.66, 0.62), the SD of
$\vec{B}_{2}$ is (0.66, 0.74, 0.64), the SD of $N_{1}$ and
$N_{2}$ are 0.25 and 0.49, the SD of $\vec{V}_{1}$ and
$\vec{V}_{2}$ are (3.0, 5.8, 7.6) and (6.9, 4.8, 4.0), the SD of
$\beta_{1}$, and $\beta_{2}$ are 0.087 and 0.117, the error cone on
the axes of the shock coordinate system is about $13^{o}$, the SD of
$M_{\rm AN1}, M_{\rm AN2}$ 0.384 and 0.169, the SD of $M_{\rm F1},M_{\rm F2}$ are
0.373 and 0.127, the SD of $\theta_{\rm BN1}$ is $6.42^{\circ}$.
\end{table}