  The brightness and height of the sodium laser guide star of adaptive optics
could vary significantly due to the temporal dynamics of sodium column density
and the mean height of sodium layer. To measure these dynamics, an independent
sodium Lidar is a necessity. Without such an instrument, it is almost
impossible to discern the cause of the brightness variation of laser guide star
from the sodium layer's dynamics or other factors from the laser itself. For
applications such as characterizing the performance of sodium laser for sodium
laser guide star generation, minutes scale short term statistics of the sodium
layers' abundance and height is extremely helpful for estimating the
contribution of sodium layer's variation to the variation of laser guide star's
brightness. In this paper, we analyzed our previous measurement of sodium layer
dynamics that has been gathered in two winters, and presented the temporal
variation statistics of sodium column density and mean height within minute
time scale based on our measurements.
