The 27-day solar rotational cycle response in the mesospheric metal layers at low latitudes

The correlation between variability in the metal layers and solar 27-day forcing during different phases of the solar 11-year cycle reveals that the response in the metal layers is much stronger during solar maximum.

The altitude-dependent correlation and sensitivity of the metal layers to the solar spectral irradiance demonstrates that there is a significant increase in sensitivity to solar rotational cycle with increasing altitude. Above 100 km, the sensitivity of the metals to changes of 10% in the solar spectral irradiance at Lyman-alpha is estimated to be −5%. A similar response is seen in Na layer measurements made by the Optical Spectrograph and InfraRed Imaging System instrument on the Odin satellite.