  We present an analysis of the long-term X-ray variability of the extreme
narrow-line Seyfert 1 (NLS1) galaxy IRAS 13224-3809 using principal component
analysis (PCA) and fractional excess variability (Fvar) spectra to identify
model-independent spectral components. We identify a series of variability
peaks in both the first PCA component and Fvar spectrum which correspond to the
strongest predicted absorption lines from the ultra-fast outflow (UFO)
discovered by Parker et al. (2017). We also find higher order PCA components,
which correspond to variability of the soft excess and reflection features. The
subtle differences between RMS and PCA results argue that the observed
flux-dependence of the absorption is due to increased ionization of the gas,
rather than changes in column density or covering fraction. This result
demonstrates that we can detect outflows from variability alone, and that
variability studies of UFOs are an extremely promising avenue for future
research.
