All Figures

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f1a.ps} } \par\vspace*{2mm}... ...\par\vspace*{2mm} {\includegraphics[width=8cm,clip]{0606f1c.ps} } \end{figure}$ Figure 1: Velocity field superimposed on a grey scale representation of the entropy perturbation for a two-dimensional simulation of an entropy bubble oscillating in an isothermal atmosphere. The asterisks shown in panel a) are used in Fig. 2a.
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8.5cm,clip]{0606f2.eps} } \end{figure}$ Figure 2: Detection of IGWs using method M1. a): time evolution of the vertical velocity recorded at three different positions in the domain (denoted by stars in Fig. 1a). b): corresponding temporal power spectra. Peaks below the buoyancy frequency N=0.82 correspond to internal gravity waves whereas the peak around $\omega =\pi$ is the fundamental acoustic mode.
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8.2cm,clip]{0606f3.eps} } \end{figure}$ Figure 3: Detection of IGWs using method M2. Left: temporal power spectra in the $(z,\omega )$ -plane for three different degrees $\ell =[0,1,2]$ . Right: the resulting spectra after an integration in depth. Dotted lines shown in all plots correspond to the bounding frequency $\omega =N\approx 0.82$ , above which g-modes cannot exist.
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f4a.ps} } \par\vspace*{2mm} {\includegraphics[width=8cm,clip]{0606f4b.ps} } \end{figure}$ Figure 4: Vertical structure of the fundamental anelastic mode (dark line) and first overtone (grey line) at $\ell = 1$ (a) and $\ell = 2$ (b). Solid lines mark the horizontal displacement $\xi _x$ while dot-dashed lines are for the vertical one $\xi _z$ . Eigenfunctions have been normalized by imposing $\int_0^1 \vert\psi_{\ell n}\vert^2\rho_0 {\rm d}z=1$ .
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=6.7cm,clip]{0606f5a.eps} } \par\vspace*{4mm} {\includegraphics[width=6.8cm,clip]{0606f5b.eps} } \end{figure}$ Figure 5: Upper: same as Fig. 3 at $\ell = 1$ , except that amplitudes have been restored using third direction. Lower: comparisons between the normalized vertical mass flux $\rho _0 v_z$ profiles deduced from the upper power spectra (solid lines) with the ones obtained from the anelastic modes shown in Fig. 4a (dotted lines).
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f6.ps} } \end{figure}$ Figure 6: Left: real parts of the complex mode amplitude ${c_{\ell n} (t)}$ for the three modes shown in Fig. 4. Right: corresponding temporal power spectra. Dotted lines mark the location of the anelastic eigenmodes $\omega _{10}=0.568,\ \omega _{11}=0.363$ and $\omega _{21}=0.575$ , respectively. Amplitudes on each plot have been multiplied by one thousand.
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f7.ps} } \end{figure}$ Figure 7: Time-evolution of the amplitude modulus $\vert c_{\ell n}\vert$ for the three modes shown in Fig. 4. Grey lines superimposed correspond to an exponential decay of the form $\vert c_{\ell n}\vert \propto \exp(-\alpha t)$ .
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f8.ps} } \end{figure}$ Figure 8: Dependence of the time-averaged kinetic energy on degree $\ell$ and radial order n.
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f9.ps} } \end{figure}$ Figure 9: $(k_x-\omega )$ diagrams which three different aspect ratios (2, 4 and 6). Crosses correspond to the anelastic frequencies given by (9).
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f10.ps} } \end{figure}$ Figure 10: Distribution of the energy contained in g-modes for different aspect ratios (2, 4 and 6) in a log-log representation.
Open with DEXTER

In the text

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f11.eps} } \end{figure}$ Figure B.1: Comparison of the complete (solid lines) and anelastic (dashed lines) normalized eigenfunctions $\xi _x$ for $\ell = 1$ and n=[0,1,2].

In the text

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f1a.ps} } \par\vspace{2mm}... ...\par\vspace{2mm} {\includegraphics[width=8cm,clip]{0606f1c.ps} } \end{figure}$	Figure 1: Velocity field superimposed on a grey scale representation of the entropy perturbation for a two-dimensional simulation of an entropy bubble oscillating in an isothermal atmosphere. The asterisks shown in panel a) are used in Fig. 2a.
Open with DEXTER

$\begin{figure} {\includegraphics[width=8.5cm,clip]{0606f2.eps} } \end{figure}$	Figure 2: Detection of IGWs using method M1. a): time evolution of the vertical velocity recorded at three different positions in the domain (denoted by stars in Fig. 1a). b): corresponding temporal power spectra. Peaks below the buoyancy frequency N=0.82 correspond to internal gravity waves whereas the peak around $\omega =\pi$ is the fundamental acoustic mode.
Open with DEXTER

$\begin{figure} {\includegraphics[width=8.2cm,clip]{0606f3.eps} } \end{figure}$	Figure 3: Detection of IGWs using method M2. Left: temporal power spectra in the $(z,\omega )$ -plane for three different degrees $\ell =[0,1,2]$ . Right: the resulting spectra after an integration in depth. Dotted lines shown in all plots correspond to the bounding frequency $\omega =N\approx 0.82$ , above which g-modes cannot exist.
Open with DEXTER

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f4a.ps} } \par\vspace*{2mm} {\includegraphics[width=8cm,clip]{0606f4b.ps} } \end{figure}$	Figure 4: Vertical structure of the fundamental anelastic mode (dark line) and first overtone (grey line) at $\ell = 1$ (a) and $\ell = 2$ (b). Solid lines mark the horizontal displacement $\xi _x$ while dot-dashed lines are for the vertical one $\xi _z$ . Eigenfunctions have been normalized by imposing $\int_0^1 \vert\psi_{\ell n}\vert^2\rho_0 {\rm d}z=1$ .
Open with DEXTER

$\begin{figure} {\includegraphics[width=6.7cm,clip]{0606f5a.eps} } \par\vspace*{4mm} {\includegraphics[width=6.8cm,clip]{0606f5b.eps} } \end{figure}$	Figure 5: Upper: same as Fig. 3 at $\ell = 1$ , except that amplitudes have been restored using third direction. Lower: comparisons between the normalized vertical mass flux $\rho _0 v_z$ profiles deduced from the upper power spectra (solid lines) with the ones obtained from the anelastic modes shown in Fig. 4a (dotted lines).
Open with DEXTER

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f6.ps} } \end{figure}$	Figure 6: Left: real parts of the complex mode amplitude ${c_{\ell n} (t)}$ for the three modes shown in Fig. 4. Right: corresponding temporal power spectra. Dotted lines mark the location of the anelastic eigenmodes $\omega _{10}=0.568,\ \omega _{11}=0.363$ and $\omega _{21}=0.575$ , respectively. Amplitudes on each plot have been multiplied by one thousand.
Open with DEXTER

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f7.ps} } \end{figure}$	Figure 7: Time-evolution of the amplitude modulus $\vert c_{\ell n}\vert$ for the three modes shown in Fig. 4. Grey lines superimposed correspond to an exponential decay of the form $\vert c_{\ell n}\vert \propto \exp(-\alpha t)$ .
Open with DEXTER

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f8.ps} } \end{figure}$	Figure 8: Dependence of the time-averaged kinetic energy on degree $\ell$ and radial order n.
Open with DEXTER

$\begin{figure} {\includegraphics[width=8.8cm,clip]{0606f9.ps} } \end{figure}$	Figure 9: $(k_x-\omega )$ diagrams which three different aspect ratios (2, 4 and 6). Crosses correspond to the anelastic frequencies given by (9).
Open with DEXTER

$\begin{figure} {\includegraphics[width=8cm,clip]{0606f10.ps} } \end{figure}$	Figure 10: Distribution of the energy contained in g-modes for different aspect ratios (2, 4 and 6) in a log-log representation.
Open with DEXTER