Impact of ENSO-induced Ozone change on MLT tides

To assess the impacts of the tropospheric ozone modulation due to El Niño on tides, we performed two simulations by using the Ground-to-topside Atmosphere Ionosphere model for Aeronomy model: zonally symmetric ozone density and longitudinal ozone variation of an El Niño pattern. Our results show that the ozone modulation strengthens (attenuates) the first symmetric mode of the DW2 (D0 and DW1) tide by ∼+5% (∼−1% and ∼−4%) from ∼20 to ∼100 km altitudes on average. These responses are probably attributed to the tropospheric ozone modulation. These responses are reasonable because both the ozone modulation and these first modes have a peak at the equator. Also, the vertical wavelengths of the first modes are about twice as long as the vertical thickness of the ozone modulation. Our results suggest that the ozone modulation due to El Niño influences the diurnal tides by a few percent because of the ozone modulation spatial structure.