An examination of high latitude upper mesosphere dynamic stability using the Nippon/Norway Svalbard Meteor Radar

Abstract

Using wind measurements from the recently installed Nippon/Norway Svalbard Meteor Radar, (NSMR) at 78°N, 16°E, we have derived wind shears, and, combining these with model Brunt‐Väisälä frequencies, have determined estimates of the gradient Richardson Number. These Richardson Number estimates parameterise the degree of stability of the upper mesosphere at a height of around 90 km. We find indications of dynamic instability in spring and autumn, with greater stability in summer.