DYNAMICAL PROPERTIES OF THE CHROMOSPHERE AND TRANSITION REGION IN THE SUPERGRANULAR NETWORK : WHAT PRECISION OF THE SPECTRAL LINE CHARACTERISTICS CAN BE REACHED ?

W. Curdt1, A. Kucera2, J. Rybák2, U. Schühle1, H. Wöhl3

1Max-Planck-Institut für Aeronomie, D-37189 Katlenburg-Lindau, Germany
2Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica, Slovakia
3Kiepenheuer-Institut für Sonnenphysik, D-79104 Freiburg, Germany

Abstract:

First SUMER results from our cooperative observations of the solar quiet atmosphere dynamics with the SUMER/SOHO and VTT/Tenerife instrumentation are presented. The contribution is focused at first on the possible real spectral, spatial and temporal resolutions which could be reached using the SUMER spectrometer measurements of the solar quiet atmosphere. Two flat-field patterns as well as different reduction methods for noise estimation and frame destretching are used for estimation of the line parameters inaccuracy caused by the instrumental effects. The overall long-term spectral line drift was found as probable consequence of the slight variations of the SUMER mechanics temperature. Finally the temporal variability of the transition region above both the supergranular internetwork and boundary is presented using the O VI 1037.61 Å  and nearby C II lines with the resolution of 2 arc sec and 15 seconds showing significant temporal and spatial variations. The significant relationship of the O VI line intensity with the remarkable red-shift was found in the network boundary but this phenomenon was found not to be unambiguous.


Key words: Sun: transition region - Sun: dynamics - instrumentation: SUMER.