Comparison of spectral line shapes of synthetic CO models for three scenarios: without any atmospheric dynamics (blue), with a day-to-night wind of 5 km s⁻¹ (red), and with a day-to-night wind of 5 km s⁻¹ and a jet of 3 km s⁻¹ (green). The unprocessed models (dash-dotted lines) were injected into the observed data, to which subsequently SYSREM was applied for 4 iterations. The ratio of the resulting residuals to the residuals of non-injected data show the distortions of the planetary signal introduced by SYSREM (dashed lines). These distortions can be reproduced by applying a filter directly to the original models, resulting in the filtered models (solid lines) which closely resemble the injected models in all three scenarios.