Seasonal cycle of H₂O₂ on Mars integrated over the Martian disk. The ordinate is the H₂O₂ volume mixing ratio in ppbv. Observed regions are centered over 20° N during northern spring and summer, and around 20° S during northern autumn and winter. Open squares: previous TEXES measurements of H₂O₂ (using GEISA 2003). Green squares: new TEXES observations (this paper). Black squares: recalibrated TEXES measurements of H₂O₂ (using GEISA 2015) and submillimeter measurements. Red curve: 3D global climate (LMD-MGCM) model including gas phase chemistry; purple curve: LMD-MGCM model considering heterogeneous chemistry on water ice grains (Lefèvre et al. 2008). The error bars correspond to the 1σ standard deviation of the H₂O₂ mean volume mixing ratio along the ±20° latitude parallel. Blue curve: 3D GEM model including gas phase chemistry (Daerden et al. 2019). All curves are calculated for a latitude of 20° N for Ls = 0–180° and 20° S for Ls = 180–360°, in order to account for the observing conditions. Blue crosses: H₂O₂ abundances inferred from the GEM model (Daerden et al. 2019) corresponding to the exact geometry of the observations. The black vertical bar indicates the autumn equinox. Error bars of the data points are ± σ.