Rogue Vertical Drafts in the Mesosphere and Lower Thermosphere: Evidence and Implications

TL;DR

This paper presents evidence of rare, extreme vertical drafts in the mesosphere and lower thermosphere, highlighting their characteristics, potential impacts, and the need for further global observations to understand their significance.

Contribution

It introduces Rogue Vertical Drafts (RVDs) as a new, significant phenomenon in the MLT, emphasizing their properties, occurrence, and potential implications for space and climate processes.

Findings

RVDs can reach vertical velocities over 50 m/s.

They occur approximately every 12 days during summer in Northern Norway.

RVDs may influence space debris and MLT climate processes.

Abstract

Observational evidence of extreme vertical velocities (|w| ge 12.5 m/s and at times greater than 50 m/s) in the mesosphere and lower thermosphere (MLT), has emerged in recent years. We refer to these events as Rogue Vertical Drafts (RVDs). They exceed five standard deviations of observed vertical velocities and appear as paired updraft-downdraft structures in varicose mode. Four-dimensional observations reveal that RVDs are intermittent, recurrent, and unpredictable. On average, they are expected to occur every sim 12 days during summer over Northern Norway, assuming a 1000 s interval. Different instruments may capture only portions of these events, for example, only upward or downward drafts when restricted to a single altitude range. Despite their rarity, their magnitudes and frequency suggest potential impacts on dust-sized matter escaping from planets, natural and anthropogenic space material, and MLT climate and processes. We propose that RVDs are a fundamental yet under-recognized feature of the MLT, underscoring the need for global observations to assess their prevalence and significance.