0000000000143187
AUTHOR
Thorsten Kaluza
Evidence of small-scale quasi-isentropic mixing in ridges of extratropical baroclinic waves
Abstract. Stratosphere–troposphere exchange within extratropical cyclones provides the potential for anthropogenic and natural surface emissions to rapidly reach the stratosphere as well as for ozone from the stratosphere to penetrate deep into the troposphere, even down into the boundary layer. The efficiency of this process directly influences the surface climate, the chemistry in the stratosphere, the chemical composition of the extratropical transition layer, and surface pollution levels. Here, we present evidence for a mixing process within extratropical cyclones which has gained only a small amount of attention so far and which fosters the transport of tropospheric air masses into the…
Composite analysis of the tropopause inversion layer in extratropical baroclinic waves
Abstract. The variability and similarities in the evolution of the tropopause inversion (TIL) layer during cyclongenesis in the North Atlantic storm track are investigated using operational meteorological analysis data (Integrated Forecast System from the European Centre for Medium-Range Weather Forecasts). For this a total amount of 130 cyclones have been analysed which evolved during the months August through October between 2010–2014 over the North Atlantic. Their paths of migration along with associated flow features in the upper troposphere/lower stratosphere (UTLS) have been tracked using the mean sea level pressure. Subsets of the 130 cyclones have been used for composite analysis us…
On the occurrence of enhanced vertical wind shear in the tropopause region: A ten year ERA5 northern hemispheric study
A climatology of the occurrence of enhanced wind shear in the UTLS is presented, which gives rise to define a tropopause shear layer (TSL). Enhanced wind shear in the tropopause region is of interest because it can generate turbulence which can lead to cross-tropopause mixing. The analysis is based on ten years of daily northern hemispheric ECMWF ERA-5 reanalysis data. The vertical extent of the region analysed is limited to the altitudes from 1.5 km above the surface up to 25 km, to exclude the planetary boundary layer as well as enhanced wind shear in higher atmospheric layers like the mesosphere/lower thermosphere. A threshold value of S2t = 4 ·&…
On the occurrence of strong vertical wind shear in the tropopause region: a 10-year ERA5 northern hemispheric study
A climatology of the occurrence of strong wind shear in the upper troposphere–lower stratosphere (UTLS) is presented, which gives rise to defining a tropopause shear layer (TSL). Strong wind shear in the tropopause region is of interest because it can generate turbulence, which can lead to cross-tropopause mixing. The analysis is based on 10 years of daily northern hemispheric ECMWF ERA5 reanalysis data. The vertical extent of the region analyzed is limited to the altitudes from 1.5 km above the surface up to 25 km, to exclude the planetary boundary layer as well as strong wind shear in higher atmospheric layers like the mesosphere–lower thermosphere. A threshold value of St2=4×10-4s-2 of t…