  A precise knowledge of the surface structure of sunspots is essential to
construct adequate input models for helioseismic inversion tools. We summarize
our recent findings about the velocity and magnetic field in and around
sunspots using HINODE observation. To this end we quantize the horizontal and
vertical component of the penumbral velocity field at different levels of
precision and study the moat flow around sunspot. Furthermore, we find that a
significant amount of the penumbral magnetic fields return below the surface
within the penumbra. Finally, we explain why the related opposite polarity
signals remain hidden in magnetograms constructed from measurements with
limited spectral resolution.
