We present a comparison of measured and theoretically modeled Lyman- a intensity ratios of hydrogenlike Al XIII impurity ions in a deuterium base plasma in the COMPASS-D tokamak. The time evolution of the intensity ratios is computed from a collisional-radiative model using measured plasma parameters and compared with line-of-sight integral values measured using a high-resolution crystal spectrometer. The variations in the modeled values follow the experimental data in the case of the L-mode plasma, taking into account variations in the electron parameters during the discharges. Apparent discrepancies between the observed and calculated ratios in the case of the H-mode plasma are attributed to line blending due to satellites of nearby Fe emission.
