All Figures

$\begin{figure} \par\includegraphics[width=15.5cm,clip]{9050fig1.ps}\end{figure}$ Figure 1: Maps of the observed area. Top: H-index in pm; middle: profile type. It is coded as follows: 0: reversal-free; 1: normal; 2: asymmetric; 3: other types. Bottom: $V_{{\rm tot}}$ , which is a measure of the net vertical magnetic flux density (Lites et al. 1999) in arbitrary units. The x-axis shows both scanning direction and time (width of a single map is eight arcsec). The y-axis is the slit direction. Both axes are in arcsec. Only 17 out of 40 scans are shown here. The time duration per scan was about 100 s.
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In the text

$\begin{figure} \par\includegraphics[width=17cm,clip]{9050fig2.ps}\end{figure}$ Figure 2: Examples of single calcium profiles with drastically different properties observed in the quiet Sun. The gray profile is the average of a few thousand profiles (cell interior and boundary). Top left: a profile with three emission peaks. Top middle: a very asymmetric profile with only a red emission peak. Top right: a very asymmetric profile with two emission peaks. Bottom: three reversal-free profiles. Note the level of the wing intensity with respect to the wing of the average profile. The dashed lines show a distance of $\pm$ 0.05 nm from the average calcium core, indicated by a vertical dotted line. The bottom left profile is an average of 59 reversal-free profiles while the other panels show single profiles. Except for the top middle and right panels, the V/R ratio was calculated using bands.
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In the text

$\begin{figure} \par\includegraphics[width=7.7cm,clip]{9050fig3.ps}\end{figure}$ Figure 3: These two examples show that the integrated intensity close to the core, either H-index or a filter, is not a reliable criterion to separate reversal-free profiles from profiles with emission peaks. Positions (in Fig. 1) of the upper and lower profile are (18.7, 30.5) and (32.6, 30.2), respectively.
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In the text

$\begin{figure} \par\includegraphics[width=15.8cm,clip]{9050fig4.ps}\end{figure}$ Figure 4: Left: stratification of the temperature in the FALA, FALC, Holweger-Müller, and C6 model atmospheres. Right: resulting calcium profiles. Except for the Holweger-Müller model atmosphere, which does not show a temperature rise, all model atmospheres result in two emission peaks. We set the nearby pseudo-continuum of the FALC profile to unity and use this normalization factor for all synthetic profiles. The observed reversal-free profile in the bottom left panel of Fig. 2 is shown in gray. All synthetic profiles convolved to the spectral resolution of the observed spectra; scattered light removed from the observed profiles.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{9050fig5.ps}\end{figure}$ Figure 5: Intensity contribution function for the inner part of the Ca II H line computed for the FALC model. The black line is the calcium profile of the model.
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In the text

$\begin{figure} \par\includegraphics[width=15.7cm,clip]{9050fig6.ps}\end{figure}$ Figure 6: Left: stratification of the temperature in the FALC model atmosphere and three modified versions of that. The thin curves represent the monochromatic source functions of these models at $\Delta \lambda = - 0.014$ nm from line center. The diamonds ( from left to right on each curve) represent the location of $\tau _{\nu } = 1$ for $\Delta \lambda = - 0.016$ , $\Delta \lambda = - 0.014$ , and $\Delta \lambda = - 0.012$ nm. The source function is similar for all three wavelengths, so that we restrict to just one source function curve per model. Right: resulting calcium profiles of the mentioned models convolved to the spectral resolution of POLIS. The ISO_30 profile is much closer to the observed reversal-free profile than the FALC model.
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In the text

$\begin{figure} \par\includegraphics[width=7.7cm,clip]{9050fig3.ps}\end{figure}$	Figure 3: These two examples show that the integrated intensity close to the core, either H-index or a filter, is not a reliable criterion to separate reversal-free profiles from profiles with emission peaks. Positions (in Fig. 1) of the upper and lower profile are (18.7, 30.5) and (32.6, 30.2), respectively.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{9050fig5.ps}\end{figure}$	Figure 5: Intensity contribution function for the inner part of the Ca II H line computed for the FALC model. The black line is the calcium profile of the model.
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