  Spectral energy distribution (SED) in protostellar disks is determined by the
disks'internal dissipation and reprocessing of irradiation from their host
stars. Around T Tauri stars, most mid-infrared (MIR) radiation (in a few to a
few ten {\mu}m wavelength range) emerge from regions around a fraction to a few
AU's. This region is interesting because it contains both the habitable zone
and the snow line. Recent observations reveal that SED variations, in the MIR
wavelength range. These variations are puzzling because they occur on time
scale (a few days) which is much shorter than the dynamical (months to years)
time scale at 1AU to a few AU's. They are probably caused by shadows casted by
inner onto outer disk regions. Interaction between disks and their misaligned
magnetized host stars can lead to warped structure and periodic SED
modulations. Rapid aperiodic SED variations may also be induced by observed
X-ray flares from T Tauri stars. These flares can significantly modulate the
ionization fraction of the gas and the net charge carried by the grains near
the surface of the inner disk. The newly charged grains may be accelerated by
the stellar or disk magnetic field and adjust their distances from the
midplane. Shadows casted by these grains attenuates the flux of stellar photons
irradiated onto regions at several AU's from the central stars. We use this
model to account for the observed rapid aperiodic SED variabilities. We suggest
regular monitoring of SED variations will not only provide valuable information
on the distribution of the disk aspect ratio near the habitable zone but also
provide a probe on the interaction between the inner regions of the disk with
the magnetosphere of their host stars.
