Volume 403, Number 2, May IV 2003
|Page(s)||725 - 730|
|Published online||06 May 2003|
Variability of EUV-spectra from the quiet upper solar atmosphere: Intensity and Doppler shift
Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, 79104 Freiburg, Germany
2 Institute of Astronomy, ETH-Zentrum, 8092 Zürich, Switzerland
3 Max-Planck-Institut für Aeronomie, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany
Corresponding author: A. Brković, email@example.com
Accepted: 11 March 2003
We have studied SUMER and CDS time series of spectra and images of quiet-Sun regions at the solar disc centre. The data contain ultraviolet emission lines sampling temperatures of the chromosphere, transition region and corona. We find a high correlation between average net Doppler shifts and relative brightness variabilities of the studied lines (correlation coefficient of 0.92), suggesting a connection between the two quantities. The anti-correlation between differential emission measures and relative brightness variabilities is weaker (correlation coefficient of -0.78). We discuss the observed relationships on the basis of differential emission measures and linear wave calculations.
Key words: Sun: chromosphere / Sun: corona / Sun: transition region / Sun: UV radiation
© ESO, 2003
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