Understanding the Madden-Julian Oscillation's Impact on Ionospheric Space Weather with COSMIC-2 Data

This study aims to investigate how the Madden-Julian Oscillation (MJO) influences space weather in the F-region ionosphere. The MJO, characterized by eastward-moving disturbances recurring every 30-96 days in tropical convection, represents a significant source of intraseasonal variability in tropical atmospheric circulation. Utilizing data from the COSMIC-2 constellation, we explore how atmospheric tides map the MJO's effects into the ionosphere. Previous studies have highlighted the notable presence of the MJO signal in both migrating and non-migrating temperature tides in the mesosphere/lower thermosphere. The mechanism involves the MJO inducing changes in global-scale waves via modulation of convective forcing, stratospheric gravity waves (GW) drag, and mean winds. These alterations depend upon various factors, including the season, magnitude, and phase (location) of the MJO. The response of ionospheric tides to the MJO is likely from either modulation of the E-region dynamo or direct upward propagation of tides, subsequently leading to corresponding changes in thermospheric composition. Our findings indicate that the MJO influences the migrating diurnal tide (DW1) in EIA electron density by approximately 10%, and by 20% for DE3. These insights are relevant for enhancing predictability of ionospheric space weather on intraseasonal timescales.