All Figures

$\begin{figure} \par\includegraphics[width=13cm,clip]{0027fg1a}\\ [3mm] \includegraphics[width=13cm,clip]{0027fg1b} \end{figure}$ Figure 1: Radiance maps (logarithmic scale) obtained in the spectral window 1532 Å to 1552 Å. From left to right: continuum (around 1539 Å); Si II (1533 Å); C IV (1548 Å); and Ne VIII (770 Å in the second order). Upper panel: CH 1 observed on 11 March 1999 between 8:05 and 12:05 UTC; bottom panel: QS observed on 8 March 1999 between 15:20 and 19:21 UTC. The dotted lines represent the border of the CH. The observations of the lines and the continuum in each interval were made simultaneously.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{0027fg2a.eps}\\ [3mm] \includegraphics[width=12.1cm,clip]{0027fg2b.eps} \end{figure}$ Figure 2: CH images in radiance (logarithmic scale) in the spectral window around 1030 Å. From left to right: continuum, H I Ly $\beta$ , C II and O VI. The equatorial CHs were observed on 11 March 1999 between 12:09 and 13:09 UTC ( upper panel) and on 8 November 1999 between 02:10 and 02:51 UTC ( bottom panel). The contours repeat the network lanes as seen in the continuum. The dotted lines represent the border of the CH.
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In the text

$\begin{figure} \par\includegraphics[width=11.6cm,clip]{0027fg3a}\\ [3mm] \includegraphics[width=11.8cm,clip]{0027fg3b} \end{figure}$ Figure 3: CH images in magnetogram and line shift. From left to right: MDI magnetogram (units: Gauss), H I Ly $\beta$ , C II and O VI (units: kilometer per second). The equatorial CHs were observed on 11 March 1999 between 12:09 and 13:09 UTC ( upper panel) and on 8 November 1999 between 02:10 and 02:51 UTC ( bottom panel). The contours repeat the network lanes as seen in the continuum in Fig. 2. The positive magnetic field is plotted in red colour, while the negative in blue. The dotted lines represent the border of the CH. Note that the Doppler shifts of the C II and O VI lines are measured relative to the chromospheric lines of O I, while the Ly $\beta$ line is referenced to its average position.
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In the text

$\begin{figure} \par\includegraphics[width=15.3cm,clip]{0027fg4a}\par\vspace*{2mm... ...g4b}\par\vspace*{2mm} \includegraphics[width=15.3cm,clip]{0027fg4c} \end{figure}$ Figure 4: Fine structures seen in the O VI line. Upper panel: equatorial CH on 11 March 1999 between 12:09 and 13:09 UTC; middle panel: equatorial CH on 8 November 1999 between 02:10 and 02:51 UTC; and bottom panel: QS on 8 March 1999 between 01:25 and 02:25 UTC. From left to right: MDI magnetogram, line width, Doppler shift and radiance. For the line widths, the red colour represents larger values. The contours repeat the network lanes as seen in the continuum.
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In the text

$\begin{figure} \par\includegraphics[width=5.2cm,clip]{0027fg5a}\hspace*{2mm} \in... ...0027fg5b}\hspace*{2mm} \includegraphics[width=5.2cm,clip]{0027fg5c} \end{figure}$ Figure 5: Relationship between the chromospheric network and line parameters in CH 1 for Si II ( left column), He I ( middle column) and C II ( right column). The histogram of the Doppler shift with a bin size of 1 km s^-1 is shown in the upper panel; the average Doppler width, integrated line radiance and continuum for each velocity interval are shown in lower panels. The bars indicate the standard deviation of each parameter. The dotted lines present the threshold of the continuum counts between the network and cell, set by the assumption that the network occupied $\approx$ 33% of the total area.
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In the text

$\begin{figure} \par\includegraphics[width=5.7cm,clip]{0027fg6a}\hspace*{2mm} \in... ...0027fg6b}\hspace*{2mm} \includegraphics[width=5.7cm,clip]{0027fg6c} \end{figure}$ Figure 6: The same format as Fig. 5 but for C IV ( left), O VI ( middle ) and Ne VIII ( right).
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In the text

$\begin{figure} \par\includegraphics[width=5.8cm,clip]{0027fg7a}\hspace*{3mm} \includegraphics[width=5.8cm,clip]{0027fg7b} \end{figure}$ Figure 7: Relationship between Doppler shifts of different lines and photospheric magnetic fields. Upper panel: the histogram of the Doppler shift of the O VI line with a bin size of 1 km s^-1; the two middle panels: the Doppler shifts of the H I Ly $\beta$ and C II lines averaged in each velocity interval of the O VI line; bottom panel: the magnetic field strengths averaged in each velocity interval of the O VI line. The vertical bars indicate the standard deviation. The dotted lines present the magnetic field strengths averaged over the CH areas observed by SUMER. Left column: data observed on 11 March 1999 in CH 1; right column: data observed on 8 November 1999 in CH 2.
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In the text

$\begin{figure} \par\includegraphics[width=13.2cm,clip]{0027fg8a}\par\vspace*{2mm... ...g8b}\par\vspace*{2mm} \includegraphics[width=13.2cm,clip]{0027fg8c} \end{figure}$ Figure 8: Average Doppler shifts in various lines versus the formation temperature in CH 1 and QS. a) CH 1; b) QS; and c) difference of the Doppler shift between the CH and QS regions.
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In the text

$\begin{figure} \par\includegraphics[width=5.7cm,clip]{0027fg6a}\hspace{2mm} \in... ...0027fg6b}\hspace{2mm} \includegraphics[width=5.7cm,clip]{0027fg6c} \end{figure}$	Figure 6: The same format as Fig. 5 but for C IV ( left), O VI ( middle ) and Ne VIII ( right).
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$\begin{figure} \par\includegraphics[width=13.2cm,clip]{0027fg8a}\par\vspace{2mm... ...g8b}\par\vspace{2mm} \includegraphics[width=13.2cm,clip]{0027fg8c} \end{figure}$	Figure 8: Average Doppler shifts in various lines versus the formation temperature in CH 1 and QS. a) CH 1; b) QS; and c) difference of the Doppler shift between the CH and QS regions.
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