Upper stratosphere-mesosphere-lower thermosphere perturbations during
the intense Arctic polar night jet in 2019-2020
Abstract
Thermal and dynamic perturbations at MLT heights during the strong
stratospheric polar vortex as measured by the meteor radar at 67°N and
the Aura satellite are presented. Mesospheric winds are dominated by
vertical shears in the zonal component and the intense alternating
north- and southward flows with a period of half a month. A temperature
reduction at 90 km height is observed in the mid-winter and likely
associated with a localized temperature increase in the upper
stratosphere. Throughout January, a long-lived ~20K
inversion layer persists just below the mesopause. These features are
likely indicative of considerable stratification in the MLT as well as a
decoupling of the middle and upper atmosphere.