Ulrike Niemeier

Department Climate Physics
Group Stratospheric Forcing and Climate
Position Scientist
phone +49 40 41173-130
Email ulrike.niemeier@mpimet.mpg.de
Room B 418

Research interest

Current interests:

  • Sulfate aerosols in the stratosphere
  • Evolution and transport of sulfur in the stratosphere (aerosol microphysical processes)
  • Understanding the micropysical processes after artificial and volcanic injections of sulfur into the stratosphere
  • Impact of radiative heating of aerosols on stratospheric dynamics (QBO, meso-cyclone)
  • Impact of volcanic eruptions and geoengineering on the climate
  • Model intercomparison GeoMIP, Member of GeoMIP steering committee, IsaMIP
  • Numerical models: ECHAM5-HAM: global general circulation model with interactive aerosol microphysics, ICON-Seamless: global non-hydrostaric, ICON-ART: adds aerosol microphysics to ICON, MPI-ESM: global ESM coupled to ocean

Physical and chemical experiments with primary school children:

born 1966 in Oldenburg, Germany

2 children


  • University of Hamburg, Meteorology, Diploma, 1992
  • Phd at University of Hamburg, Meteorological Institute 1997
  • Ph.D. thesis: Chemical reactions in a mesoscale model - boundary conditions and simulations


  • Research Center, University of Science and Technology, Hong Kong (April 1997 - March 1998)
  • Department of Chemistry, University of Science and Technology, Hong Kong (April 1998 - June 1998)
  • Max Planck Institute for Meteorology, Hamburg  (October 1998 - December 2000)
  • IPSL, Laboratoire d'Aerenomie, Paris (August 2001 - October 2003)
  • Max Planck Institute for Meteorology, Hamburg (since November 2003)
  • NCAR, Boulder (Guest scientist Aug to Dec 2016)

  • EU Project IMPLICC
  • DFG special priority program on geoengineering
  • MOZART atmospheric chemistry and transport
  • Global influence of traffic emissions (road, ship) on the Earth-System
  • Metras non-hydrostatic mesoscale model
  • Transport of air pollutions in Hong Kong

This is a short list of my publications. See the full list here.

Niemeier, U., Wallis, S., Timmreck, C., van Pham, T., & von Savigny, C. (2023). How the Hunga Tonga—Hunga Ha'apai water vapor cloud impacts its transport through the stratosphere: Dynamical and radiative effects. Geophysical Research Letters, 50, e2023GL106482. https://doi.org/10.1029/2023GL106482


Haywood, J. and S. Tilmes (Lead Authors), F. Keutsch, U. Niemeier, A. Schmidt, D. Visioni, and P. Yu, Stratospheric Aerosol Injection and its Potential Effect on the Stratospheric Ozone Layer, Chapter 6 in Scientific Assessment of Ozone Depletion: 2022, GAW Report No. 278, 509 pp., WMO, Geneva, 2022.

Quaglia, I., Timmreck, C., Niemeier, U., Visioni, D., Pitari, G., Brodowsky, C., Brühl, C., Dhomse, S. S., Franke, H., Laakso, A., Mann, G. W., Rozanov, E., and Sukhodolov, T.: Interactive stratospheric aerosol models' response to different amounts and altitudes of SO2 injection during the 1991 Pinatubo eruption, Atmos. Chem. Phys., 23, 921–948, doi.org/10.5194/acp-23-921-2023, 2023.

Niemeier, U., Riede, F., and Timmreck, C.: Simulation of ash clouds after a Laacher See-type eruption, Clim. Past, 17, 633–652, https://doi.org/10.5194/cp-17-633-2021, 2021.

Niemeier, U., Richter, J. H., and Tilmes, S.: Differing responses of the quasi-biennial oscillation to artificial SO2 injections in two global models, Atmos. Chem. Phys., 20, 8975–8987, doi.org/10.5194/acp-20-8975-2020, 2020.

Franke, H., Niemeier, U., and Visioni, D.: Differences in the quasi-biennial oscillation response to stratospheric aerosol modification depending on injection strategy and species, Atmos. Chem. Phys., 21, 8615–8635, https://doi.org/10.5194/acp-21-8615-2021, 2021

Brenna, H., Kutterolf, S., Mills, M. J., Niemeier, U., Timmreck, C., & Krüger, K. Decadal disruption of the QBO by tropical volcanic supereruptions. Geophysical Research Letters, 48, e2020GL089687, https://doi.org/10.1029/2020GL089687, 2021

Niemeier, Ulrike, Timmreck, Claudia, and Krüger, Kirstin: Revisiting the Agung 1963 volcanic forcing – impact of one or two eruptions, Atmos. Chem. Phys., 19, 10379–10390, https://doi.org/10.5194/acp-19-10379-2019, 2019.

Niemeier Ulrike and Simone Tilmes, Sulfur injections for a cooler planet, Science, Vol. 357, Issue 6348, pp. pp 246-248, DOI: 10.1126/science.aan3317, 2017. (Solicited)

Niemeier, Ulrike and Hauke Schmidt: Changing transport processes in the stratosphere by radiative heating of sulfate aerosols, Atmos. Chem. Phys., 17, 14871-14886, https://doi.org/10.5194/acp-17-14871-2017, 2017

Niemeier, U., & Timmreck, C. (2015). What is the limit of climate engineering by stratospheric injection of SO 2?. Atmospheric Chemistry and Physics, 15(16), 9129-9141, doi:10.5194/acp-15-9129-2015.

Niemeier, U., H. Schmidt, K. Alterskjær, and J. E. Kristjánsson, Solar irradiance reduction via climate engineering--climatic impact of different techniques, Journal of Geophysical Research, DOI:10.1002/2013JD020445.

This paper was chosen as a research spotlight by JGR

Stratospheric sulfate aerosols

Climate engineering

"Geoengineering" or "climate engineering" may be defined as the deliberate large-scale manipulation of climate. Climate engineering may result in undesirable side effects for crucial parts of the Earth system and humankind. Therefore it is necessary to study the possible efficiency, risks and implications. Numerical models are the only possible tool for performing scientific studies. Complex climate models will be used to quantify the effectiveness and side effects of such geoengineering concepts aiming at a reduction of the incoming solar radiation.

Read more

Role of fine ash

Dated to ca. 13,000 years ago, the Laacher See (East Eifel Volcanic Zone) eruption was one of the largest mid-latitude Northern Hemisphere volcanic events of the Late Pleistocene. This eruptive event not only impacted local environments and human communities, but also NH climate. We have simulated the evolution of the fine ash and sulfur under present-day meteorological conditions mirroring the empirically known ash transport distribution

Rotating ash impacts transport, as the heating of the ash plays a crucial role for the transport of ash and sulfate. Depending on the altitude of the injection, the volcanic cloud begins to rotate one to three days after the eruption. The rotation:

  • changes the transport pattern shortly after the eruption. In a simulation withash the zonal transport is reduced, the meridional transport is increased.
  • adds a southerly component to the transport vectors. The consequences are stronger transport to low-latitudes (Fig. 4), and later arrival of the volcanic cloud in the Arctic regions.
  • increases sulfate lifetime, burden and radiative forcing.