  The ionosphere introduces chromatic distortions on low frequency radio waves,
and thus poses a hurdle for 21-cm cosmology. In this paper we introduce
time-varying chromatic ionospheric effects on simulated antenna temperature
data of a global 21-cm data analysis pipeline, and try to detect the injected
global signal. We demonstrate that given turbulent ionospheric conditions, more
than 5\% error in our knowledge of the ionospheric parameters could lead to
comparatively low evidence and high root-mean-square error (RMSE), suggesting a
false or null detection. When using a constant antenna beam for cases that
include data at different times, the significance of the detection lowers as
the number of time samples increases. It is also shown that for observations
that include data at different times, readjusting beam configurations according
to the time-varying ionospheric conditions should greatly improve the
significance of a detection, yielding higher evidences and lower RMSE, and that
it is a necessary procedure for a successful detection when the ionospheric
conditions are not ideal.
