  We analyzed the full Stokes spectra using simultaneous measurements of the
photospheric (FeI 630.15 and 630.25 nm) and chromospheric (MgI b2 517.27 nm)
lines. The data were obtained with the HAO/NSO Advanced Stokes Polarimeter,
about a near disc center sunspot region, NOAA AR 9661. We compare the
characteristics of Stokes profiles in terms of Doppler shifts and asymmetries
among the three spectral lines, which helps us to better understand the
chromospheric lines and the magnetic and flow fields in different magnetic
regions. The main results are: (1) For penumbral area observed by the
photospheric FeI lines, Doppler velocities derived from Stokes I (Vi) are very
close to those derived from linear polarization profiles (Vlp) but
significantly different from those derived from Stokes V profiles (Vzc), which
provides direct and strong evidence that the penumbral Evershed flows are
magnetized and mainly carried by the horizontal magnetic component. (2) The
rudimentary inverse Evershed effect observed by the MgI b2 line provides a
qualitative evidence on its formation height that is around or just above the
temperature minimum region. (3) Vzc and Vlp in penumbrae and Vzc in pores
generally approach their Vi observed by the chromospheric MgI line, which is
not the case for the photospheric FeI lines. (4) Outer penumbrae and pores show
similar behavior of the Stokes V asymmetries that tend to change from positive
values in the photosphere (FeI lines) to negative values in the low
chromosphere (MgI line). (5) The Stokes V profiles in plage regions are highly
asymmetric in the photosphere and more symmetric in the low chromosphere. (6)
Strong red shifts and large asymmetries are found around the magnetic polarity
inversion line within the common penumbra of the Delta spot. This study thus
emphasizes the importance of spectro-polarimetry using chromospheric lines.
