and MARCS model atmospheres with T$_{\rm eff}$ = 4000K and log $g$ = 1 (red line) and T$_{\rm eff}$ = 5500K and log $g$ = 4 (blue line). The model from the APOGEE grid is denoted by a solid line, the corresponding ATLAS9 model from @castelli01 is denoted by a dotted line, the MARCS model is denoted by dashed line. The panels show the mass column ($m$), temperature ($T$), gas pressure ($P$), electron number density ($N_{\rm e}$) as a function of the logarithm of optical depth (log $\tau$), and the relative difference between the ATLAS9 (A$_{\rm K}$), MARCS (A$_{\rm M}$) calculations presented in this paper and @castelli01 (C$_{\rm K}$). ](figure03.eps){width="3.5in"}

Comparing our MARCS and ATLAS9 models to the Castelli-Kurucz grid
-----------------------------------------------------------------

Figure 3 illustrates examples of the atmospheric structures for two models with solar composition, one for $T_{\rm eff} = 4000$K and log $g = 1$ (red line) and the other for $T_{\rm eff} = 5500$K and log $g = 4$ (blue line). There are four double panels showing the parameter dependence with Rosseland optical depth of the mass column (top-left panel), temperature (top-right), gas pressure (bottom-left) and electron number density (bottom-right). The dashed, solid, and dotted lines correspond to 