Characteristics of Helium Bulges and the Impact of Martian Year 34 Global Dust Storm Using MAVEN/NGIMS Observations and MarsPCM and MGITM Simulations

Abstract We investigate spatiotemporal characteristics of helium (He) bulges using data from the Neutral Gas and Ion Mass Spectrometer aboard NASA's Mars Atmosphere and Volatile EvolutioN Mission and numerical simulations from the Mars Planetary Climate Model (MarsPCM). During equinoxes, we observed a He bulge at equatorial latitudes in addition to the mid‐to‐high latitude bulges reported in previous studies. This bulge is consistent with MarsPCM simulations. In addition, MarsPCM predicts a He bulge with larger latitudinal and poleward extents than previous studies suggest, persisting throughout the Martian year (MY) under nominal dust conditions. During equinoxes, the bulges span 85°N–90°S latitudes on the nightside. During solstices, the southern winter bulge is more dynamic between 0 and 8 hr local time (LT), and the northern one between 18 and 24 hr LT. Seasonal migration of He bulges occurs around solar longitudes ( L s ) ∼ 50° and ∼183°, transitioning toward the winter hemisphere. We compare MarsPCM simulations using “climatology” and specific “MY 34” dust scenarios, alongside Mars Global Ionosphere Thermosphere Model (MGITM) simulations, to examine the impact of “MY 34” Global Dust Storm (GDS) during its pre‐storm ( L s ∼ 184°), peak ( L s ∼ 207°), and decay ( L s ∼ 240°) phases. Simulations indicate that the He bulge became most distorted during the storm's peak while remaining on the dayside. These distortions likely result from enhanced damping of meridional circulation at polar latitudes, contributing to the suppression of He bulges during high‐dust seasons.