  We investigate the statistics of the intensity distributions as function of
the wavelength for Ca II H and the CA II IR line at 854.2 nm to estimate the
energy content. We derived the intensity variations at different heights of the
solar atmosphere as given by the line wings and line cores of the two spectral
lines. We converted the observed intensities to absolute energy units employing
reference profiles calculated in NLTE. We also converted the observed intensity
fluctuations to brightness temperatures assuming LTE. The rms fluctuations of
the emitted intensity are about 0.6 (1.2) W/m2 ster pm near the core of the Ca
IR line (Ca II H), corresponding to intensity fluctuations of about 20% (30%).
For the line wing, we find rms values of about 0.3 W/ m2 ster pm for both
lines, corresponding to relative fluctuations below 5%. The rms shows a local
minimum for wavelengths forming at about 130 km height, but otherwise increases
from the wing to the core. The rms brightness temperature fluctuations are
below 100 K for the photosphere and up to 500 K in the chromosphere. The
skewness of the intensity distributions is close to zero in the outer line wing
and positive throughout the rest of the spectrum. The skewness shows a
pronounced maximum on locations with photospheric magnetic fields for
wavelengths in between the line wing and the line core, and a global maximum at
the very core for both magnetic and field-free locations. The energy content of
the intensity fluctuations is insufficient to create a similar temperature rise
in the chromosphere as predicted in most reference models of the solar
atmosphere. The enhanced skewness between photosphere and lower solar
chromosphere on magnetic locations indicates a mechanism which solely acts on
magnetized plasma.
