  A unique challenge for data analysis with the Laser Interferometer Space
Antenna (LISA) is that the noise backgrounds from instrumental noise and
astrophysical sources will change significantly over both the year and the
entire mission. Variations in the noise levels will be on time scales
comparable to, or shorter than, the time most signals spend in the detector's
sensitive band. The variation in the amplitude of the galactic stochastic GW
background from galactic binaries as the antenna pattern rotates relative to
the galactic center is a particularly significant component of the noise
variation. LISA's sensitivity to different source classes will therefore vary
as a function of sky location and time. The variation will impact both overall
signal-to-noise and the efficiency of alerts to EM observers to search for
multi-messenger counterparts.
