Organisation: JGU > Faculty 08 > Institute for Atmospheric Physics > AG Hoor
Research: JGU > Faculty 08 > Physics > Atmospheric Physics & Environmental Sciences > AG Hoor

The central research topics of the group of Peter Hoor are related to transport and mixing processes affecting the tropopause region or the extratropical upper troposphere / lower stratosphere (ExUTLS, see e.g. Gettelman et al., 2011).

Changes of the distributions of trace gases, like water vapor, ozone and ozone depleting substances, and thin cirrus clouds in the upper troposphere and lower stratosphere (UTLS) strongly impact radiative forcing of the Earth's climate and surface temperatures (Solomon et al., 2010), and are of key importance for understanding climate change (Hegglin and Shepherd, 2009; Riese et al., 2012). Transport and mixing in the extratropical upper troposphere / lower stratosphere (ExUTLS) play a key role for the quantitative understanding of the distribution of these radiatively active species (Riese et al., 2010). The formation of the extratropical transition layer (ExTL) around the tropopause, which exhibits chemical characteristics of both the stratosphere and the troposphere (Hoor et. al, 2002, 2004; Pan et al., 2004), is a direct consequence of the underlying frequent small scale mixing processes.

The AG Hoor combines airborne measurements of trace gases with Lagrangian analysis tools and meteorological analysis and reanalysis data as well as Earth system models to

1) investigate processes at the tropopause leading to cross tropopause exchange

2) to identify transport regimes and quantify time scales of transport in the UTLS region

3) identify transport pathways in the troposphere

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Projections of climate change rely on an adequate representation of UTLS processes and their feedbacks in climate models. In the Collaborative Research Centre TPChange this will be addressed by a combination of field measurements, laboratory studies, theoretical approaches, and multiscale numerical modelling. Based on an improved understanding of relevant processes at different scales, we will develop parameterisations to improve state-of-the-art climate models. Our goal is to specify the impact of UTLS processes on composition, dynamics and ultimately on future climate and climate variability..

OCTAV-UTLS is a SPARC activity, which analyses trends of ozone and water vapour specifically in the UTLS region. The activity is lead by Irina Petropavlovkhikh (NOAA), Peter Hoor (JGU) and Luis Millan (JPL) who replaces Gloria Manney (NWRA)

The distribution of tracers in the Upper Troposphere and Lower Stratosphere (UTLS) shows a large spatial and temporal variability, caused by competing transport, chemical, and mixing processes near the tropopause, as well as variations in the tropopause itself. This strongly affects quantitative estimates of the impact of radiatively active substances, including ozone and water vapour, on surface temperatures, and complicates diagnosis of of dynamical processes such as stratosphere troposphere exchange (STE). The community thus faces challenge of optimally exploiting the existing portfolio of observations to better understand the physical composition of the UTLS, including past long-term changes in trace gas distributions and the processes that control them.

This activity will focus on improving the quantitative understanding of the UTLS’s role in climate and the impacts of stratosphere-troposphere exchange (STE) processes on air quality. Achieving this goal requires a detailed characterization of existing measurements (from aircraft, ground-based, balloon, and satellite platforms) in the UTLS, including understanding how their quality and sampling characteristics (spatial and temporal coverage, resolution) affect the representativeness of these observations.

One key aspect of this activity will be to develop and apply common metrics to compare UTLS data using a variety of geophysically-based coordinate systems (e.g., tropopause, equivalent latitude, jet-focused) using meteorological information from reanalysis datasets. This approach will provide a framework for comparing measurements with diverse sampling patterns and thus will leverage the meteorological context to derive maximum information on UTLS composition and its relationships to dynamical variability.

The activity will produce recommendations for data comparisons in the UTLS region based on specific techniques/instruments. We will provide an assessment of gaps in current geographical/temporal sampling of the UTLS region that limit determining variability and trends, and suggest future measurement strategies that would help fill those gaps.

Water vapor variations in the extratropical upper troposphere and lower stratosphere (UTLS) have been shown to crucially affect atmospheric circulation and climate. For example, climate feedbacks due to stratospheric water vapor are dominated by trends in this region. Although UTLS water vapor has been the subject of considerable research due to its importance for climate, progress in understanding its impacts has been limited. This is largely because satellite and in-situ observations carry large uncertainties, and atmospheric models exhibit some of their largest biases in this region. The proposed ISSI team will bring together experts from the different fields of satellite and in-situ observations, process and climate modelling, dynamics and process understanding to make significant progress in understanding, observing and simulating water vapor in the UTLS.

The Priority Program (Schwerpunktprogramm) SPP 1294 "Atmospheric and Earth System Research with HALO” – "High Altitude and Long Range Research Aircraft" - is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation). It supports research for the investigation of atmospheric and Earth system related processes.

Our group led several campaigns with HALO in the past focusing on topics in the upper troposphere and lower stratosphere (WISE, SouthTRAC, PHILEAS).
Additionally, our group participated in several campaigns (TACTS/ESMVal, ASCCI, NAWDIC).

Oliver Eppers (now AG Schneider, MPIC)
Philipp Joppe (now AG Borrmann/Köllner, JGU/MPIC)
Maximilian Büttner
Franziska Köllner (now AG Borrmann, IPA, JGU)
Björn Kluschat (now TÜV Rheinland)

Jens Krause (now Excelitas)
Stefan Müller (now enviscope GmbH)
Christiane Hofmann (now Bonn university)
Florian Berkes (now FZ Jülich)
Matthias Wandel (now DWD)

Martin Richter-Rose (now WKN AG)
Magdalena Bertelmann (now DWD)
Philipp Waleska (now enviscope GmbH)
Janina Wendling (now Wetterkontor)
Robert Gutmann (now at Framatome GmbH)

Autoren: Chun Hang Chau, Peter Hoor, Katharina Kaiser, and Holger Tost

2025

Autoren: Madhuri Umbarkar, Daniel Kunkel, Annette Miltenberger, Hans-Christoph Lachnitt, Thorsten Kaluza, Cornelis Schwenk, and Peter Hoor

2025

Autoren: Linda Smoydzin, Vera Bense, Heiko Bozem, Philipp Joppe, Daniel Kunkel, Hans-Christoph Lachnitt, Holger Tost, Andreas Zahn, Helmut Ziereis, Martin Riese, and Peter Hoor

2025

Autoren: Heiko Bozem, Philipp Joppe, Yun Li, Nicolas Emig, Armin Afchine, Anna Breuninger, Joachim Curtius, Stefan Hofmann, Sadath Ismayil, Konrad Kandler, Daniel Kunkel, Arthur Kutschka, Hans-Christoph Lachnitt, Andreas Petzold, Sarah Richter, Timo Röschenthaler, Christian Rolf, Lisa Schneider, Johannes Schneider, Alexander Vogel, and Peter Hoor

2025

Autoren: Linda Ort, Andrea Pozzer, Peter Hoor, Florian Obersteiner, Andreas Zahn, Thomas B. Ryerson, Chelsea R. Thompson, Jeff Peischl,
Róisín Commane, Bruce Daube, Ilann Bourgeois, Jos Lelieveld, and Horst Fischer

2025

Autoren: Nicolas Emig, Annette K. Miltenberger, Peter M. Hoor, and Andreas Petzold

2025

The AG Hoor operates instrumentation for the measurements of different trace gases. The instruments are based on spectroscopic methods, in particular on absorption spectroscopy in the infrared and UV wavelength range. As a light source either Quantum Cascade Lasers (QCLs) or diode and UV lamps are used. You can find a short description of the individual measurement instruments below.

For the simultaneous measurement of the trace gases nitrous oxide (N2O) and carbon monoxide (CO) the Quantum Cascade Laser based spectrometer UMAQS is used. It is based on the “Aerodyne Research Inc.“ Quantum Cascade Laser Mini Monitor which uses an astigmatic multi path Herriot cell with an optical pathlength of 76m. This instrument applies the direct absorption spectroscopy. For operating the instrument on airborne platforms the pressure within the measurement cell is controlled at 70 hPa. To account for instrument drifts in-situ calibration on a regular time base during operation are possible. The instrument has a resolution of 1 Hz which is limited by the exchange time of the measurement cell. This allows to measure atmospheric concentrations of N2O with a noise level of 0.08 ppbv (2σ) and a reproducibility of 0.2 ppbv (2σ). For CO measurements the noise level amounts to 0.38 ppbv (2σ) and for the reproducibility we reach 0.7 ppbv (2σ).

The 2B Technologies Dual Beam Ozone Monitor is designed to enable accurate measurements of atmospheric ozone over a wide dynamic range extending from a limit of detection of 1 ppbv to an upper limit of 100 ppmv based on the well established technique of absorption of ultraviolet light at 254 nm. The ozone molecule has an absorption maximum at 254 nm, coincident with the principal emission wavelength of a low-pressure mercury lamp. Fortunately, few molecules found at significant concentrations in the atmosphere absorb at this wavelength. The Model 205 Dual Beam Ozone Monitor makes use of two detection cells to improve precision, baseline stability, and response time. An air pump draws sample air into the instrument at flow rate of approximately 1.5 L/min. A pair of solenoid valves switch in unison so as to alternately send ozone-scrubbed air and unscrubbed air through the two absorption cells. Thus, the intensity of light passing through ozone scrubbed air (Io) is measured in Cell 1 while the intensity of light pass through unscrubbed air (I) is measured in Cell 2. Every 2 seconds, the solenoid valves switches, changing which cell receives ozone-scrubbed air and which cell receives unscrubbed air. Combined with other improvements, this made it possible to reduce the time between ozone measurements to 2 seconds, making the instrument the fastest UV-based ozone monitor on the market, while still retaining the small size, weight, and power requirements. For 10-s averaging, a precision of 1.0 ppb is achieved.

A comprehensive analysis of airborne measurement data requires an initial characterization of the instrument. However, the use of numerical model data as well as analysis and reanalysis products help to put the in-situ data into the meteorological context and to understand the atmospheric processes governing the distribution of trace species in the atmosphere. In our group we use Eulerian and Lagrangian numerical models as well as analysis and reanalysis products from numerical weather prediction centers (mainly ECMWF).

Lagrangian models allow to trace the history of individual air parcels which have been measured during a flight. These models have also proven to be very useful to interpret measurement data which have been subject to tropospheric long range transport (e.g., into the Arctic) or to transport in the stratosphere and across the tropopause. Eulerian models allow to study the atmosphere very idealized and to address specific processes or to simulate the Earth system comprehensively.

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Berufsfelderfahrung
Instructor: Dr. Heiko Bozem; Univ.-Prof. Dr. Peter Hoor
Berufspraktikum
Instructor: Dr. Heiko Bozem; Univ.-Prof. Dr. Peter Hoor
Einführung in die Meteorologie
Instructor: Univ.-Prof. Dr. Peter Hoor; Dr. Daniel Kunkel
Einführung in die Meteorologie (Zukunftszertifikat)
Instructor: Univ.-Prof. Dr. Peter Hoor; Dr. Daniel Kunkel
Einführungsveranstaltung Meteorologie (B.Sc. & M.Sc.)
Instructor: Dr. Heiko Bozem
Einführungsveranstaltung Umweltwissenschaften
Instructor: Dr. Heiko Bozem
Extratropische Wettersysteme
Instructor: Dr. Daniel Kunkel
Klimatologie und Klima
Instructor: Dr. Heiko Bozem
Meteorologisches Fortgeschrittenenpraktikum A
Instructor: Dr. Heiko Bozem
Meteorologisches Fortgeschrittenenpraktikum B
Instructor: Dr. Heiko Bozem
Meteorologisches Seminar
Instructor: Dr. Heiko Bozem
Meteorologisches Seminar I
Instructor: Dr. Heiko Bozem
Methodenkenntnis
Instructor: Dr. Heiko Bozem; Univ.-Prof. Dr. Peter Hoor; Dr. Daniel Kunkel; Dr. Franziska Köllner; Jun.-Prof. Dr. Annette Miltenberger; Dr. Philipp Reutter; Dr. Michael Riemer; Dr. Miklos Szakall; Univ.-Prof. Dr. Holger Tost; Prof. Dr. Thomas Wagner; Dr. Ralf Weigel; Univ.-Prof. Dr. Volkmar Wirth
Projekt Umweltwissenschaften
Instructor: Dr. Heiko Bozem; Univ.-Prof. Dr. Peter Hoor; Dr. Daniel Kunkel; Dr. Franziska Köllner; Jun.-Prof. Dr. Annette Miltenberger; Dr. Philipp Reutter; Dr. Michael Riemer; Univ.-Prof. Dr. Peter Spichtinger; Dr. Miklos Szakall; Univ.-Prof. Dr. Holger Tost; Dr. Ralf Weigel; Univ.-Prof. Dr. Volkmar Wirth
Seminar zur Einführung in die Anwendung des Computers in den Atmosphärenwissenschaften
Instructor: Dr. Daniel Kunkel
Stratosphäre: Zusammensetzung und Transport
Instructor: Univ.-Prof. Dr. Peter Hoor

SoSe 2026

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For general inquiries regarding open research positions please contact utls@uni-mainz.de

Cooperating partners

Berufspraktikum