  The variability of the broad absorption lines is investigated for a broad
absorption line (BAL) QSO, SDSS J022844.09+000217.0 (z = 2.719), with 18
SDSS/BOSS spectra covering 4128 days in the observed frame. With the ratio of
the rms spectrum to the mean spectrum, the relative flux change of the
BAL-trough is larger than that of the emission lines and the continuum. Fitting
the power-law continuum and the emission line profiles of \civ $\lambda$1549
and \siiv$\lambda$1399, we calculate the equivalent width (EW) for different
epochs, as well as the continuum luminosity and the spectral index. It is found
that there is a strong correlation between the BAL-trough EW and the spectral
index, and a weak negative correlation between the BAL-trough EW and the
continuum luminosity. The strong correlation between the BAL-trough EW and the
spectral index for this one QSO suggests that dust is intrinsic to outflows.
The weak correlation between the BAL variability and the continuum luminosity
for this one QSO implies that the BAL-trough variation is not dominated by
photoionization.
