20.5.2019: New paper available in ACP Kaluza et al. (2019)

Composite analysis of the tropopause inversion layer in extratropical baroclinic waves

The evolution of the tropopause inversion layer (TIL) during cyclogenesis in the North Atlantic storm track is investigated using operational meteorological analysis data (Integrated Forecast System from the European Centre for Medium-Range Weather Forecasts). For this a total of 130 cyclones have been analysed during the months August through October between 2010 and 2014 over the North Atlantic. Their paths of migration along with associated flow features in the upper troposphere and lower stratosphere (UTLS) have been tracked based on the mean sea level pressure field. Subsets of the 130 cyclones have been used for composite analysis using minimum sea level pressure to filter the cyclones based on their strength.

The composite structure of the TIL strength distribution in connection with the overall UTLS flow strongly resembles the structure of the individual cyclones. Key results are that a strong dipole in TIL strength forms in regions of cyclonic wrap-up of UTLS air masses of different origin and isentropic potential vorticity. These air masses are associated with the cyclonic rotation of the underlying cyclones. The maximum values of enhanced static stability above the tropopause occur north and northeast of the cyclone centre, vertically aligned with outflow regions of strong updraft and cloud formation up to the tropopause, which are situated in anticyclonic flow patterns in the upper troposphere. These regions are co-located with a maximum of vertical shear of the horizontal wind. The strong wind shear within the TIL results in a local minimum of Richardson numbers, representing the possibility for turbulent instability and potential mixing (or air mass exchange) within regions of enhanced static stability in the lowermost stratosphere.

15.4.2019: Kunkel et al. 2019: Paper on WISE mission at ACPD

One of the key topics of the WISE mission has been addressed by the Paper of D.Kunkel, who analyzes the occurrence of turbulence and mixing directly at the tropopause above the ridge region of an extratropical cyclone ( The paper bridges the in-situ observations with the fundamental process view from idealized simulations of baroclinic life cycles. These indicate that strong shear in regions of high static stability at the tropopause may lead to tracer exchange and mixing.

29.3.2019: Rhine-Main Universities undertake research on transport processes in the tropopause region

The Initiative Funding for Research of the Rhine-Main Universities (RMU) is currently supporting a cross-university project in the field of meteorology and climatology. The objective is to determine the time scales of transport processes in the tropopause, a region in the Earth's atmosphere at an elevation of 10 to 20 kilometers. The processes and composition in the tropopause region strongly affect surface temperatures and climate.

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20. - 21. March 2019

The WISE group will meet for a data meeting from 20. - 21. March 2019 at Johannes Gutenberg University in Mainz.

22.2.2019: New Paper in ACP

A new study led by Hannes Schulz (AWI) on the vertical variability of black carbon (BC) in high Arctic spring and summer is available in ACP ( Our group contributed airborne carbon monoxide (CO) measurements and LAGRANTO kinematic back trajectories.

12.2.2019: Bozem et al. 2019 in ACPD

A new diagnostic for the determination of the polar dome boundary is presented using airborne in-situ CO and CO2 data as well as 10-day kinematic back trajectories in the European and Canadian Arctic in July 2014 and April 2015. Using the tracer derived boundary the analysis of the recent transport history of air masses within the polar dome reveals significant differences of dome extent and transport properties between spring and summer (

19.11.2018: Kaluza et al., 2018 in ACPD

A new view on the static stability structure of extratropical cyclones is presented using a composite analysis of cyclones identified from ECMWF operational analysis data. The analysis shows, that even in regions of high static stability conditions favorable for cross tropopause exchange exist, which are linked to the occurrence of strong vertical shear of horizontal winds (

7 - 9 November 2018, OCTAV-UTLS workshop in Mainz

The 2nd meeting of the SPARC activity OCTAV-UTLS took place at the Helmholtz Institute (HIM) in Mainz. Speakers from the United States, UK, France and Gernany discussed new approaches and potential methods to account for the dynamical induced variability of ozone observations from different observations systems. These include radio sondes, LIDAR, aircraft measurements and satellite observations. The group defined a set of common diagnostic approaches to be applied to the different data sets, which allow to directly compare distributions and trends of ozone from different platforms and observational geometries consistently in the UTLS region. The comparison will be done at the next meeting in the United States at the Table Mountain lidar site.

13.10.2018: New discussion paper in ACPD

A summary paper about the advances of our understanding in the processes controlling Arctic aerosols during the NETCARE project led by Jonathan Abbatt (University of Toronto) and W. Richard Leaitch (Environment and Climate Change, Toronto) has been published for discussion in ACPD.
Our group contributed with airborne measurements during NETCARE 2014 and NETCARE 2015 as well as with FLEXPART simulations to analyze air mass histories.

02.10.2018: New discussion paper in ACPD

A new study led by Meng Si (University of British Columbia) on ice-nucleating particles in the Canadian High Arctic during spring 2016 is available in ACPD.
Our group provided FLEXPART results for a source attribution of the ice-nucleating particles.

01.-05.10.2018: SPARC General Assembly in Kyoto, Japan

This week the SPARC GA takes place in Kyoto, Japan.
Peter Hoor will present first results on the WISE campaign and an overview on the OCTAV-UTLS activities.

31.08.2018: OCTAV-UTLS workshop, 7 - 9 November 2018, Mainz

The SPARC OCTAV - UTLS working group will meet for a data meeting from 7 - 9 November 2018 at the Johannes Gutenberg University in Mainz. We will host this meeting which will take place at the Helmholtz Institute Mainz (HIM).

More information can be found here.

24.08.2018: New discussion paper in ACPD

A new study led by Megan Willis (University of Toronto) on the vertical distribution of aerosols in the high Arctic is available now in ACPD.
Our group contributed airborne measurement data, ECMWF analysis data as well as results from FLEXPART simulations.

07.08.2018: HALO mission CAFE AFRICA started

Two member of our group, Franziska Köllner and Oliver Eppers, participate in the current HALO mission CAFE-AFRICA (lead: MPIC, Mainz) which is based on Cap Verde and studies the influence of the massive biomass burning emissions from southern Africa on the atmospheric oxidation capacity over the tropical and South Atlantic Ocean.

More information can be found here.