Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

Abstract

Abstract. In summer 2013 the WADIS-1 sounding rocket campaign was conducted at the Andøya Space Center (ACS) in northern Norway (69 • N, 16 • E). Among other things, it addressed the question of the variability in mesosphere/lower thermosphere (MLT) turbulence, both in time and space. A unique feature of the WADIS project was multi-point turbulence sounding applying different measurement techniques including rocket-borne ionization gauges, VHF MAARSY radar, and VHF EISCAT radar near Tromsø. This allowed for horizontal variability to be observed in the turbulence field in the MLT at scales from a few to 100 km. We found that the turbulence dissipation rate, ε varied in space in a wavelike manner both horizontally and in the vertical direction. This wavelike modulation reveals the same vertical wavelengths as those seen in gravity waves. We also found that the vertical mean value of radar observations of ε agrees reasonably with rocket-borne measurements. In this way defined ε radar value reveals clear tidal modulation and results in variation by up to 2 orders of magnitude with periods of 24 h. The ε radar value also shows 12 h and shorter (1 to a few hours) modulations resulting in one decade of variation in ε radar magnitude. The 24 h modulation appeared to be in phase with tidal change of horizontal wind observed by SAURA-MF radar. Such wavelike and, in particular, tidal modulation of the turbulence dissipation field in the MLT region inferred from our analysis is a new finding of this work.

Derivation of turbulent energy dissipation rate with the Middle Atmosphere Alomar Radar System (MAARSY) and radiosondes at Andøya, Norway

“…During the WADIS sounding rocket campaign in 2013 (Strelnikov et al, 2014), there were 14 launches of balloon-borne radiosondes (model: MarkIIa DGPS (LOS), (p/n 1648-611)) at the radar site of MAARSY. The ascent rate of the radiosondes (RS) used in this study was roughly 5 m s −1 .…”

“…In this study, we compare radar-based estimates of ε (based on the Middle Atmosphere Alomar Radar SYstem -MAARSY -spectral width data) with radiosonde data applying a so-called Thorpe analysis (Thorpe, 1977;Clayson and Kantha, 2008;Wilson et al, 2011). These radiosonde measurements were obtained during the WADIS sounding rocket campaign in 2013 as described in Strelnikov et al (2014). We are hence able to validate the radar estimates of turbulence by comparing them with the simultaneous in situ measurements with radiosondes.…”

Estimate of size distribution of charged MSPs measured in situ in winter during the WADIS-2 sounding rocket campaign

“…The main goal of the mission was to study propagation of gravity waves (GWs) from their sources in the troposphere to their level of dissipation in the MLT and quantification of their contribution to the energy budget of the MLT. For an overview of the WADIS project and its main mission the reader is referred to Strelnikov et al (2017).…”

On the short-term variability of turbulence and temperature in the winter mesosphere

“…Experimental studies with rocket borne ionization gauges have shown that small-scale turbulence is present in the very stable inversion layer, and in some cases, indicates mixing in the quasiadiabatic layer above the inversion (Lehmacher and Lübken, 1995;Lehmacher et al, 2006Lehmacher et al, , 2011Szewczyk et al, 2013;Strelnikov et al, 2017). Since rocket measurements of neutral turbulence are relatively complex and costly, they often only provide a single profile of temperature and turbulence, while model results allow the analysis in the full spatialtemporal domain.…”