Meridional distributions of C₄H₂, C₂N₂, and C₃H₄ from 2006 (northern winter) to 2014 (mid-northern spring) at 15 mbar (or an altitude of ~85 km). “a” refers to Teanby et al. (2009a), where the same gases as in this study were measured with the same CIRS detector (FP1); “b”, “c”, and “d” respectively refer to Coustenis et al. (2010), Bampasidis et al. (2012), and Coustenis et al. (2016), C₄H₂ and C₃H₄ were measured with the CIRS detector FP3, probing slightly higher pressure levels (10 mbar) than this study. In the south pole, from 2006 to 2015, the volume mixing ratios of the three species strongly increased, while the other latitudes exhibit weak seasonal variations. Unlike C₄H₂ and C₃H₄, C₂N₂ abundance at mid-northern latitudes decreases from 2012. Error bars show relative errors as derived in Sect. 3.6.