Intermittency of Waves in the Polar Upper Troposphere and Lower Stratosphere Over Northern Norway Using MAARSY

Abstract

We investigate the absolute momentum flux (AMF) and vertical wind variance $\left(\rho \overline{w^{\prime 2}}\right)$ of gravity waves (GWs) along with intermittencies in the upper troposphere and lower stratosphere (UTLS) during 2017–2022 using the Middle Atmosphere Alomar Radar System at Andøya, Norway (69.30°N, 16.04°E). We categorized the AMF and $\rho \overline{w^{\prime 2}}$ into different period ranges (30 min–2 hr, 2–6 hr, 6–13 hr, 13 hr–1 day, and 30 min–1 day) to study the significance of short- and long-period waves. The selection of these period bands was based on the boundary conditions of the available spectra: 30 min (Nyquist frequency), 13 hr (inertial period), and 1 day (based on our interest in maximum long-period oscillations). Through the investigation of the AMF and $\rho \overline{w^{\prime 2}}$, we wish to determine in detail the GW characteristics at northern polar latitudes. Furthermore, it is crucial to assess the intermittency as it considerably influences and alters the GW attributes. Our novel results indicate for both AMF and $\rho \overline{w^{\prime 2}}$: (a) seasonal variation with minima during summer (May–September); (b) higher magnitude in the upper troposphere (<9.00 km) than the lower stratosphere; (c) short-period components (30 min–2 hr, 2–6 hr) are more intermittent in the entire UTLS; and (d) the long-period components (6–13 hr, 13 hr–1 day) demonstrate lower (higher) intermittency in the upper troposphere (lower stratosphere) in summer implying a plausible wave-filtering mechanism.