Decadal solar signal in ozone and temperature through the mesosphere of Northern tropics

To investigate the effects of decadal solar variability on ozone and temperature in the mesosphere of the Northern tropics, data obtained from the Halogen Occultation Experiment (HALOE) aboard Upper Atmospheric Research Satellite (UARS) during the period 1992–2005 are analyzed using a multifunctional regression model. The inferred annual-mean solar signal in ozone is found to be insignificant in the lower mesosphere whereas it is of the order of 5%/100 sfu in the upper mesosphere. Seasonal variation of ozone response to solar variability indicates a strong positive response (22–30%/100 sfu) during summer and autumn between 5E-3 and 0.01 mb pressure levels (∼80–85 km). The annual mean temperature response is found to be of the order of 0.5–1 K/100 sfu. Significant positive temperature response is observed during winter and autumn in the lower mesosphere and during summer and spring in the upper mesosphere. Results obtained in the present study are also compared with the results obtained by other workers.

Research Highlights
► Solar response to HALOE ozone show seasonal variation at the pressure levels between 75 and 85 km.
► Observed solar response to ozone shows a peak near 80 km during summer and autumn seasons.
► Significant positive solar response to HALOE temperature is observed during winter and autumn in the lower mesosphere.
► In the upper mesosphere, solar response to temperature is significant during summer and spring.
► Temperature response varies from 0.1 K to 1.2 K/100 sfu during most of the seasons except during summer.