The 27-Day and 11-Year Solar Cycle Signals in Global Means of Middle Atmosphere Parameters Observed by the Aura Microwave Limb Sounder

Both the 27-day and the 11-year solar cycles of extreme ultraviolet radiation (EUV) influence the Earth’s middle atmosphere. The influences of solar cycles on geopotential height (or pressure) are analysed by using the Aura Microwave Limb Sounder (Aura/MLS) observations from 2004 to 2021. Composite analysis shows that the mesospheric 27-day variation in the global mean geopotential height is correlated with the 27-day variation of solar radio flux (F10.7 cm index), which is a proxy of solar EUV. The maximum of the geopotential height has a phase lag of 4 days with respect to the maximum of EUV. The 11-year solar cycle has a sensitivity of 492 m/100 sfu in global mean geopotential height at about 94 km high. Similarly, the influences of solar cycles on the global means of middle atmospheric temperature, ozone, and water vapour are derived and discussed.