Eigil Kaas

Professor in Meteorology and Climate Dynamics

Research interests
Ongoing projects, centres and duties
Teaching activities
PhD projects
Master degree projects
Recent reviewed publications

Research interests

My main fields of interest are in climate research with focus on climate dynamics, meteorology and numerical methods used in atmospheric models (climate and numerical weather prediction), and coupled atmospheric chemistry transport models..

Ongoing projects, centres and duties

  • Section head of the Climate and Geophysics Section at the Niels Bohr Institute.

Teaching activities

I am currently teaching and responsible for the following semester (block) courses:

  • Atmospheric Physics (Geofysik 1) (block 1 Sep-Nov). This an undergraduate course introducing atmospheric physics and dynamics based on the popular book by Wallace and Hobbs.

  • Dynamical Meteorology – 1 (block 3 Feb-Apr). This is an undergraduate course introducing the various types of waves in the atmosphere, and, based on Boussinesq and/or quasi-geostrophic approximations, also the large scale dynamical structures and instabilities of the atmosphere.

  • General circulation of the atmosphere (block 2 Nov-Jan). This is a graduate course analysing the averaged global circulation and structure/state of the atmosphere. One main point is the identification of the role of the large-scale atmospheric (Rossby) waves. The course also covers balances of energy and angular momentum, dynamically caused variability and meridional transports of, e.g., heat.

  • Dynamical models for climate and Numerical Weather Prediction (NWP) (block 4 Apr-Jun). This is graduate course on atmospheric dynamical modelling and data assimilation for use in climate research and numerical weather prediction (NWP).

Previously (since 2006) I taught the following courses:

  • Climate Models, Observations of the Past and the Present, and Projected Climate Change including Sea Level Rise (MSc)

  • Geofysisk fluiddynamik (BSc)

  • Introduktion til geofysik (Geofysik1) (Bsc)

  • Klimadynamik (Bsc)

  • Klimafysik (Bsc)

  • Numerical methods in atmosphere and ocean models (MSc)

  • Satellite geophysics (MSc)

I have also been teacher and co-organiser on various PhD summer schools.

Ongoing PhD projects (main supervisor)

  • Ida Margrethe Ringgaard studies the interaction between varying Arctic sea ice and the global climate system with special emphasis on the impact of abrupt sea ice changes on the Greenland ice sheet. Funded by the Ice2Ice project and in collaboration with CIC and DMI.

  • Martin Olesen uses the HIRHAM model to downscale past and present weather conditions over Greenland with special emphasis on the role of sea ice variations in the Nordic Seas. Funded by the Ice2Ice project and in collaboration with CIC and DMI.

  • Alexander Kurganskiy develops a new module for simulation and forecasts of pollen concentration in the Enviro-HIRLAM model system. Alexander is a so called double PhD between NBI and the Russian State Hydrometeorological University, RSHU in St. Petersburg. In collaboration with DMI.

  • Kasper Hintz is an industrial PhD in collaboration with the private company Vaavud. The idea in this project is to use unconventional crowd source data – mainly wind and pressure – to enhance the skill in nowcasting, i.e., forecasts with a lead time of a few hours. The output of the project could be new and better apps for smartphones

Recent PhD students (finalised 2009-2015)

  • Brian Sørensen. Brian developed the ENVIRO-HIRLAM system further. The main emphasis was on improving the dynamical coupling between pollutants and dynamical core. This project was part of CEEH (www.ceeh.dk).

  • Ayoe Buus Hansen. Ayoe combined a locally mass conserving semi-Lagrangian transport scheme with the atmospheric chemical modules used at the National Environmental Research Institute. This project was part of CEEH (www.ceeh.dk)

  • Ivana Cvijanović. Ivana studied the climate dynamics related to abrupt climate change with main focus on potential atmospheric re-organisations.

  • Ulrik Smith Korsholm (in collaboration with DMI). Ulrik modelled the indirect effects of aerosol. Ulrik is co-developer of the ENVIRO-HIRLAM model at DMI.

  • Till Rasmussen. Till analysed and modelled the Sea Ice in the Nares Strait between Greenland and Canada (in collaboration with Nicolai Kliem, DMI).

Ongoing master degree projects

  • Anne Borrits (planned 2018) works with the DMI slippery road forecasting system. The aim is to develop and test a processing and quality control system for thermal mapping data measurements taken along roads of the Danish road network. The project is carried out in collaboration with the Danish Road Directorate and DMI.

  • Andreas Nikolai Pedersen (planned 2017) investigates the impact of climate change on severe precipitation. Andreas will perform case studies with severe convective precipitation using the WRF model. The idea is to change the initial conditions and the lateral boundary conditions to study the impact of increased temperature and related increased specific humidity on the amount of precipitation in each case.

  • Peter Valentin Ukkonen (planned 2017) uses information from a regional climate model to model extreme precipitation in a warmer climate.

Finalised master theses (finalised 2008-2016)

  • Joshua Rahbek (2016) worked on physically based statistical downscaling of extreme precipitation events in a warmer climate with special focus on precipitation changes in the UK.

  • Kyle Matthew Honsinger (2016) analysed changes of large scale climate variability in a warmer climate as simulated with the EC-Earth climate model. The main result obtained was that a change in ENSO variability significantly impact and enhance the interannual climate variability over the North Pacific. In collaboration with Shuting Yang at DMI.

  • Emy Alerskans (2016) combined the use of a new explicit filter for stabilising non-hydrostatic models based on the fully compressible Euler equations with a new explicit time-splitting time scheme. This is an alternative to the use of (semi-)implicit discretisation.

  • Johanna Eggeling (2016) analysed relationships between temperature and the occurrence of extreme precipitation over the Brittish Isles.

  • Andreas Michael Lang (2016) worked on the impact of Sea ice thickness in the Arctic. Andreas modified the atmospheric component of the EC-EARTH global climate model so that it can take into account the influence of gradually reduced sea ice thickness. In collaboration with Shuting Yang at DMI.

  • Mathilde Thorn Ljungdal (2016) used termistor-string measurements from arctic drifters (buoys on drifting Arctic sea ice) to estimate the heat conductivity and actual heat flux through the ice. The results were used to validate corresponding time series of total surface heat flux in the ERA interrim re-analysis data set. Drifter data were made available by Leif Toudal at DMI.

  • Kasper Hintz (2015) assimilated (nudged) high resolution precipitation radar data information into the HIRLAM system at DMI aiming at improving short-term forecasts of heavy precipitation (“Nowcasting”). His special focus was on the importance of the length of the model time step which appeared to be quite important for resolving the most intensive convection. In collaboration with DMI.

  • Abdulai Ademola Kayode (2015) used GPS data collected at the Greenland ice sheet. “Demi” (his nickname) reprocessed the data using “Bernese” software using alternative parameters for ionospheric and tropospheric correction. The application was on the use of GPS to quantify surface movements of the Greenland Ice Sheet.

  • Zhenhua Sun (2013, 30 ECTS) used high temporal resolution atmospheric data to drive a simple hydrological model, which was set up for conditions in the city of Århus. The aim was to investigate the role of green infrastructures on the hydrology and pollution.

  • Rune H. Gjermundbo (2013) is using an atmospheric GCM coupled to a mixed layer ocean model to study mechanisms responsible for Arctic amplification with main emphasis on understanding the relative role of local (i.e. Arctic) versus remote (i.e. tropical) processes/mechanisms. External (main) supervisor: Peter Lang Langen (DMI/DKC).

  • Kaija Jumppanen Andersen (2013) is using satellite altimetry to calculate geostrophic currents and changes therein in the North Atlantic over the last decades. Comparisons with estimated sea level atmospheric pressure (SLP) and wind stress are made and a simple model describing sea level as function of SLP is being set up. External supervisor: Ole Baltazar Andersen (DTU Space).

  • Danny Høgsholt (2013) applied a combined time-splitting using a forward-backward approach with a semi-Lagrangian scheme in order to solve the fully compressible Euler equations in simple 2-dimensional convective plume model.

  • Cecilie Drost Aakjær (2013) analysed the dynamics of Arctic Ocean freshwater storage in the EC-Earth coupled climate model. External supervisors: Steffen M. Olsen and Torben Schmith (DMI)

  • Bjarke Tobias Olsen (2013) studied mixing in models employing the Hybrid Eulerian – Lagrangian (HEL) method for solving continuity equations. The main emphasis was to identify an optimal degree of flow-dependent mixing in order to obtain realistic cascades of energy etc. to small scales

  • Rasmus Anker Pedersen (2013) used an atmospheric GCM with different prescribed sea-ice concentrations to study the impact of sea ice reductions on the Arctic tropospheric temperature changes. External (main) supervisor: Peter Lang Langen (DMI/DKC).

  • Philip Tarning-Andersen (2012) studied aerosol-cloud microphysics in a one dimensional atmospheric model, with emphasis on a simple parameterization of effective droplet radius in warm clouds (In collaboration with Ulrik Smith Korsholm, DMI).

  • Karis Anneke Kürstein Glibbery (2011) used different satellite data sets for outgoing long wave radiation (OLR) to verify the long wave feedbacks in the EC-Earth climate model running at DMI (In collaboration with Shuting Yang, DMI).

  • Matilde Marie Brandt Jensen (2011) studied and analysed Arctic sea ice thinning over the period 1979-2008 using a number of different remote sensing based data (In collaboration with Rasmus Tonboe, DMI)

  • Maria Elisabeth Wulff (2011). Maria used ice core data for recent years and observed precipitation at Greenland SYNOP stations to identify a correction data base for the precipitation simulated in the HIRHAM regional climate model. The correction is needed to obtain reasonable atmospheric data for driving an ice sheet model (not part of the study). (In collaboration with Gudfinna Adalsgeirdottir and others at the Danish Climate Centre, DMI).

  • Leif Skovbo (2009). Leif investigated the realism of certain verifiable feedbacks in IPCC climate models and used this to perform a model weighting for future climate scenarios.

  • Ayoe Buus Hansen (2009). Ayoe performed a two-dimensional intercomparison of semi-Lagrangian transport schemes and the ASD algorithm used in the atmospheric chemical modules at the National Environmental Research Institute. This project was part of CEEH (www.ceeh.dk)

  • Joakim Refslund Nielsen (2009). Joakim implemented and tested a new anti-diffusive monotonic filter in combination with a locally mass conserving semi-Lagrangian transport scheme in the HIRLAM model used at DMI.

  • Brian Sørensen (2009). Brian implemented and tested a new quasi-Lagrangian vertical coordinate in combination with a locally mass conserving semi-Lagrangian transport scheme in the HIRLAM model used at DMI.

  • Allan Christensen (2009). Allan implemented and tested a locally mass conserving semi-Lagrangian transport scheme in the HIRLAM model used at DMI.



Full CV , four page CV , two page CV , one page CV, recent publication, publications.

Recent reviewed scientific publications

(pdf-copies can be delivered on request, also for accepted manuscripts):

Kaas, E., 2008: A simple and efficient locally mass conserving semi-Lagrangian transport scheme. Tellus, 60A, 305-320.

Machenhauer, B., E. Kaas, and P. H. Lauritzen, 2008: “Finite volume methods in meteorology”. Chapter of 119 pages in ”COMPUTATIONAL METHODS FOR THE ATMOSPHERE AND THE OCEANS” published by Elsevier. Editors: Roger Temam, Joe Tribbia and Philippe Ciarlet. 784 pages. ISBN 978-0-444-51893-4.

Lauritzen, P.H., E. Kaas, B. Machenhauer and K. Lindberg, 2008: A mass-conservative version of the semi-implicit semi-Lagrangian HIRLAM. Quart. J. Roy. Meteor. Soc.: Vol. 134, Issue 635, pp. 1583–1595, [Abstract], Pdf-version.

Kaas, E., 2009: “Menneskeskabte klimaændringer”. Ugeskrift for læger, 171/44, 3165-3168. (in Danish).

Kaas, E., and J. R. Nielsen (2010): A mass conserving quasi-monotonic filter for use in semi-Lagrangian models. Monthly Weather Review, 138, No. 5. 1858-1876.

Rasmussen, T. A. S, N. Kliem, E. Kaas (2010) Modelling the sea ice in the Nares Strait. Ocean Modelling, 35, No. 3 161-172.

Rasmussen, T. A. S, N. Kliem, E. Kaas (2011) The effect of climate change on the sea ice and the hydrography in the Nares Strait. Atmosphere-Ocean. doi:10.1080/07055900.2011.604404.

Cvijanovic, I, P. L. Langen, and E. Kaas (2011): Weakened atmospheric energy transport feedback in cold glacial climates. Clim. Past, 7, 1061-1073, doi:10.5194/cp-7-1061-2011.

A. B. Hansen, J. Brandt, J. H. Christensen, and E. Kaas (2011): Semi-Lagrangian methods in air pollution models, Geosci. Model Dev., 4, 511-541, doi:10.5194/gmd-4-511-2011.

Funder S., H. Goosse, H. Jepsen, E. Kaas, K. H. Kjær, N. J. Korsgaard, N. K. Larsen, H. Linderson, A. Lyså, P. Möller, J. Olsen, E. Willerslev (2011): A 10,000-Year Record of Arctic Ocean Sea-Ice Variability—View from the Beach, Science. 5 August 2011: 747-750. [DOI:10.1126/science.1202760].

Cvijanovic, I, P. L. Langen, E. Kaas, and Peter D. Ditlevsen (2013): Southward Intertropical Convergence Zone shifts and implications for an atmospheric bipolar seesaw. J. climate, http://dx.doi.org/10.1175/JCLI-D-12-00279.1

Sørensen, B., E. Kaas, U. S. Korsholm (2013): A mass conserving and multi-tracer efficient transport scheme in the online integrated Enviro-HIRLAM model. Geosci. Model Dev., 6,1029-1042, doi:10.5194/gmd-6-1029-2013, http://www.geosci-model-dev.net/6/1029/2013/gmd-6-1029-2013.pdf

Rathmann, N. M., S. Yang and E. Kaas (2013): Tropical cyclones in enhanced resolution CMIP5 experiments. Clim Dyn, DOI 10.1007/s00382-013-1818-5.

Krueger, O., F. Feser, L. Bärring, E.Kaas, T. Schmith, H. Tuomenvirta and H. von Storch (2013): Comment on “Trends and low frequency variability of extra-tropical cyclone activity in the ensemble of Twentieth Century Reanalysis” by Xiaolan L. Wang, Y. Feng, G. P. Compo, V. R. Swail, F. W. Zwiers, R. J. Allan, and P.D. Sardeshmukh, Climate Dynamics, published online, DOI 10.1007/s00382-013-1814-9

Brandt, J., J. D. Silver, J. H. Christensen, M. S. Andersen, J. H. Bønløkke, T. Sigsgaard, C. Geels, A. Gross, A. B. Hansen, K. M. Hansen, G. B. Hedegaard, E. Kaas and L. M. Frohn (2013): Contribution from the ten major emission sectors in Europe and Denmark to the health-cost externalities of air pollution using the EVA model system – an integrated modelling approach. Atmos. Chem. Phys., 13, 7725-7746. doi:10.5194/acp-13-7725-2013.

Brandt, J, J. D. Silver, J. H. Christensen, M. S. Andersen, J. H. Bønløkke, T. Sigsgaard, C. Geels, A. Gross, A. B. Hansen, K. M. Hansen, G. B. Hedegaard, E. Kaas and L. M. Frohn (2013): Assessment of past, present and future health-cost externalities of air pollution in Europe and the contribution from international ship traffic using the EVA model system. Atmos. Chem. Phys., 13, 7747-7764, doi:10.5194/acp-13-7747-2013.

Kaas, E., B. Sørensen, C. C. Tscherning and M. Veicherts (2013): Multi-processing least squares collocation: Applications to gravity field analysis. Journal of Geodetic Science. Volume 3, Issue 3, Pages 219–223, DOI: 10.2478/jogs-2013-0025

Kaas, E., B. Sørensen, P. H. Lauritzen and A. B. Hansen (2013): A hybrid Eulerian Lagrangian numerical scheme for solving prognostic equations in fluid dynamics. Geosci. Model Dev. 6, 2023-2047, doi:10.5194/gmd-6-2023-2013

Baklanov, A., K. H. Schluenzen, P. Suppan, J. Baldasano, D. Brunner, S. Aksoyoglu, G. Carmichael, J. Douros, J. Flemming, R. Forkel, S. Galmarini, M. Gauss, G. Grell, M. Hirtl, S. Joffre, O. Jorba, E. Kaas, M. Kaasik, G. Kallos, X. Kong, U. Korsholm, A. Kurganskiy, J. Kushta, U. Lohmann, A. Mahura, A. Manders-Groot, A. Maurizi, N. Moussiopoulos, S. T. Rao, N. Savage, C. Seigneur, R. Sokhi, E. Solazzo, S. Solomos, B. Sørensen, G. Tsegas, E. Vignati, B. Vogel, and Y. Zhang, (2013): Online coupled regional meteorology-chemistry models in Europe: current status and prospects. Atmos. Chem. Phys. Atmos. Chem., 14, 317–398, doi:10.5194/acp-14-317-2014.

Lauritzen, P.H., P.A. Ullrich, C. Jablonowski, P.A. Bosler, D. Calhoun, A.J. Conley, T. Enomoto, L. Dong, S. Dubey, O. Guba, A.B. Hansen, E. Kaas, J. Kent, J.F. Lamarque, M.J. Prather, D. Reinert, V.V. Shashkin, W.C. Skamarock, B. Sørensen, M.A. Taylor, and M.A. Tolstykh (2013): A standard test case suite for two-dimensional linear transport on the sphere: results from a collection of state-of-the-art schemes. Geosci. Model Dev., 7, 105–145, doi:10.5194/gmd-7-105-2014.

A. Acheampong, C. Fosu, L. K. Amekudzi, and E. Kaas (2015): Comparison of precipitable water over Ghana using GPS signals and reanalysis products. J. Geod. Sci.; Volume 5, Issue 1, ISSN (Online) 2081-9943, DOI: 10.1515/jogs-2015-0016, November 2015.

Lang, A., S. Yang, and E. Kaas (2017), Sea ice thickness and recent Arctic warming, Geophys. Res. Lett., 44, 409–418, doi:10.1002/2016GL071274.

UPDATED February 2017

Niels Bohr Institute
Juliane Maries Vej 30
DK-2100 Copenhagen,

+ 45 35 32 05 14
Mobile phone:
+ 45 26 14 93 02


Section head of the Climate and Geophysics Section and part time affiliated to the Centre for Ice and Climate

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