An understanding of the spatial and temporal variation of a non-uniform combustion environment can aid in the optimization of industrial and power production processes. Absorption spectroscopy is often used to quantify temperature and species mole fraction, but is limited to line-of-sight measurements. Without an understanding of the non-uniform flow-field, it is difficult to interpret species mole fraction quantities using standard absorption spectroscopy approaches. We demonstrate a new approach to characterize the species mole fraction by using computational fluid dynamics models to inform the data interpretation through a pathlength weighting function. The technique is demonstrated in a heated buoyant jet above a catalytic combustor, by performing a fine vertical scan and 2D scan of the combustor. The results suggest the path length correction can have a significant impact on the measured values, which may lead to new conclusions.