Katrin Lonitz

Research Department, Earth System Assimilation Section, Actively Sensed Observations Group

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Katrin Lonitz is working on the assimilation of GNSS-RO data as part of ROMSAF. Previously, she has been working on the all-sky assimilation (assimilation under clear, cloudy and rainy conditions) of microwave imager radiances.

Professional interests: 
  • assimilation of GNSS-RO data
  • observation operator
  • combination of observations with numerical models
  • clouds and precipitation
  • all-sky assimilation of microwave radiances


Career background: 

08/2020 - today     Research Scientist

04/2014 - 07/2020 EUMETSAT fellow at ECMWF

02/2014 - 03/2014 PostDoc, Max Planck Institute for Meteorology in Hamburg (Germany)

06/2010 - 01/2014 Doctoral Student, Max Planck Institute for Meteorology in Hamburg (Germany)

04/2010 - 05/2010 Research Assistant on board of R/V Polarstern cruise trip ANT-XXVI/4 from Punta  Arenas (Chile) to Bremerhaven (Germany)

10/2004 - 03/2010 Diploma student, University of Leipzig (Germany)


Peer-reviewed publications

A. J. Geer, P. Bauer, K. Lonitz, V. Barlakas, P. Eriksson, J. Mendrok, A. Doherty, J. Hocking and P. Chambon (2021): Bulk hydrometeor optical properties for microwave and sub-millimetre radiative transfer in RTTOV-SCATT v13.0, Geosci. Model Dev., Vol. 14, p. 7497–7526, ​doi.org/10.5194/gmd-14-7497-2021

Lonitz, K. and A. J. Geer (2019): Assessing the impact of different liquid water permittivity models on the fit between model and observations, Atmos. Meas. Tech., Vol. 12 , p.405–429, ​doi.org/10.5194/amt-12-405-2019

A. J. Geer, K. Lonitz, P. Weston, M. Kazumori, K. Okamoto, Y. Zhu, E. Huichun Liu, A. Collard, W. Bell , S. Migliorini, P. Chambon, N. Fourrié, M.-J. Kim, C. Köpken-Watts and C. Schraff (2018): All-sky satellite data assimilation at operational weather forecasting centres, Quarterly Journal of the Royal Meteorological Society, Vol. 144 (713), p.1191-1217, doi.org/10.1002/qj.3202

A. J. Geer, F. Baordo, N. Bormann, P. Chambon, S. J. English, M. Kazumori, H. Lawrence, P. Lean, K. Lonitz and C. Lupu (2017): The growing impact of satellite observations sensitive to humidity, cloud and precipitation, Quarterly Journal of the Royal Meteorological Society, Vol. 143 (709), p.3189–3206, doi:10.1002/qj.3172

Stevens, B., D. Farrell, L. Hirsch, F. Jansen, L. Nuijens, I. Serikov, B. Brügmann, M. Forde,  H. Linne, K. Lonitz and J. M. Prospero (2016): The Barbados Cloud Observatory: Anchoring Investigations of Clouds and Circulation on the Edge of the ITCZ, Bulletin of the American Meteorological Society, Vol. 97 (5), p.787-801, doi:10.1175/BAMS-D-14-00247.1

Lonitz, K., B. Stevens, L. Nuijens, V. Sant, L. Hirsch and A. Seifert (2015): The Signature of Aerosols and Meteorology in Long-Term Cloud Radar Observations of Trade Wind Cumuli, Journal of the Atmospheric Sciences, Vol. 72 (12), doi:10.1175/JAS-D-14-0348.1

Nuijens, L., I. Serikov, L. Hirsch, K. Lonitz and B. Stevens (2014): The distribution and variability of low-level cloud in the North-Atlantic trades, Quarterly Journal of the Royal Meteorological Society, Vol. 140(684), doi:10.1002/qj.2307

Lonitz, K. and A. Horváth (2011): Comparison of MISR and Meteosat-9 cloud motion winds, Journal of Geophysical Research - Atmospheres, Vol. 116, doi:10.1029/2011JD016047.


Other publications

A. J. Geer, K. Lonitz, D. I. Duncan and N. Bormann (2022): Improved surfacetreatment for all-sky microwave observations, ECMWF Technical Memorandum 894

Lonitz, K., A. J. Geer (2022) and N. Bormann: Towards assimilating surface sensitive microwave channels over land, EUMETSAT/ECMWF Fellowship Programme Research Report 58 [elibrary]

Lonitz, K. and A. Geer (2020): Reducing the drying effect through a water vapour correction to the all-sky error model, EUMETSAT/ECMWF Fellowship Programme Research Report 53 [elibrary]

Lonitz, K. and A. Geer (2017): Effect of assimilating microwave imager observations in the presence of a model bias in marine stratocumulus, EUMETSAT/ECMWF Fellowship Programme Research Report 44 [elibrary]

Lean, P., A. Geer, and K. Lonitz (2017): Assimilation of Global Precipitation Mission (GPM) Microwave Imager (GMI) in all-sky conditions, ECMWF Technical Memorandum 799 [elibrary]

Forbes, R., A. Geer, K. Lonitz and M. Ahlgrimm (2016): Reducing systematic errors in cold-air outbreaks, ECMWF Newsletter Feature Article 146, doi:10.21957/s41h7q7l

Lonitz, K. and A. J. Geer (2015): New screening of cold-air outbreak regions used in 4D-Var all-sky assimilation, EUMETSAT/ECMWF Fellowship Programme Research Report 35 [elibrary]

thumbnail photo of Katrin Lonitz
Contact Details:
katrin . lonitzecmwf . int
Tel. +44 (0) 118 9499649