  To investigate the origins of the warm absorbers in active galactic nuclei
(AGNs), we study the ionization-state structure of the radiation-driven
fountain model in a low-mass AGN (Wada et al. 2016) and calculate the predicted
X-ray spectra, utilizing the spectral synthesis code Cloudy (Ferland et al.
2017). The spectra show many absorption and emission line features originated
in the outflowing ionized gas. The O VIII 0.654 keV lines are produced mainly
in the polar region much closer to the SMBH than the optical narrow line
regions. The absorption measure distribution of the ionization parameter
($\xi$) at a low inclination spreads over 4 orders of magnitude in $\xi$,
indicating multi-phase ionization structure of the outflow, as actually
observed in many type-1 AGNs. We compare our simulated spectra with the high
energy-resolution spectrum of the narrow line Seyfert 1 galaxy, NGC 4051. The
model reproduces slowly outflowing (a few hundreds km s$^{-1}$) warm absorbers.
However, the faster components with a few thousands km s$^{-1}$ observed in NGC
4051 are not reproduced. The simulation also underproduces the intensity and
width of the O VIII 0.654 keV line. These results suggest that the ionized gas
launched from sub-parsec or smaller regions inside the torus, which are not
included in the current fountain model, must be important ingredients of the
warm absorbers with a few thousands km s$^{-1}$. The model also consistently
explains the Chandra/HETG spectrum of the Seyfert 2 galaxy, the Circinus
galaxy.
