Analysis of turbulence reports and ERA5 turbulence diagnostics in a tropopause-based vertical framework

Abstract

In the tropopause region turbulence exhibits a common feature with posing a threat for aviation as well as presenting a pathway for cross tropopause exchange. However, current numerical weather prediction and in particular climate models still struggle to resolve a large part of the dynamics responsible for turbulence generation. This renders high resolution observations of turbulence to be very valuable to identify the spatio-temporal distribution of turbulence. In this study we use aircraft observations along with reanalysis data over the North Atlantic during winter season to analyze turbulence occurrence. Using a tropopause-based coordinate system, we found that turbulence occurs within a sharp unimodal distribution which maximizes just below the tropopause. Turbulence also significantly affects the first 2 km above the tropopause which highlights its potential impact on the formation of the so called extratropical mixing layer around the tropopause.