Long-term temperature and ozone response to natural drivers in the mesospheric region using 16 years (2005–2020) of TIMED/SABER observation data at 5–15°N

Abstract

The long-term mesospheric (60–100 km) temperature and ozone volume mixing ratio variability during the period of January 2005 to December 2020 were analyzed to obtain trends and their response to natural influences using the SABER, an instrument onboard the TIMED satellite to obtain observation data in the latitude range of 5°N–15°N. A wavelet analysis technique has been used to identify the dominant periodic oscillations in mesospheric temperature and ozone. Using the proxy data of F10.7, Nino 3.4, and zonal wind index (QBO at 30 hPa), the mesospheric response to natural drivers was investigated using a multiple linear regression technique. Among the three natural drivers, solar radio flux (F10.7) is the dominant contributor to mesospheric variability rather than ENSO and QBO. It influences negatively the lower mesosphere (60–80 km), and above 80 km, it responds positively in temperature (2.6 K), whereas ozone responds with a constant negative value (0.12ppmv) up to 80 km, and after it influences by a maximum positive value of 0.7 ppmv. At 80 km, the temperature and ozone respond in phase to all natural influences (F10.7, ENSO, and QBO), and are out of phase below and above 80 km. Both the temperature and the ozone reveal cooling trends (-0.85 K/decade and −0.12 ppmv/decade) of the the lower mesosphere (60–80 km) and are followed by the upper mesospheric (85–100 km) warming trends (1.25 K/decade and 0.27 ppmv/ decade) over the low latitudes. In general, natural influences affected the mesospheric temperature more strongly than the ozone volume mixing ratio. Our results are expected to be an updated and reliable estimation of the mesospheric temperature and ozone variability for the equatorial mesosphere.