projects, centres and duties
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
am currently teaching and responsible for the following semester
Physics (Geofysik 1). This an undergraduate course
introducing atmospheric physics and dynamics based on the popular
book by Wallace and Hobbs.
Meteorology – 1. This is an undergraduate course
introducing the various types of waves in the atmosphere, and,
based on quasi-geostrophic theory, also the large scale dynamical
structures and instabilities of the atmosphere.
circulation of the atmosphere. 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 waves. The course also covers
balances of energy and angular momentum, dynamically coursed
variability and meridional transports of, e.g., heat.
models for climate and Numerical Weather Prediction (NWP).
This is graduate course on on atmospheric dynamical modeling and
data assimilation for use in climate research and numerical
weather prediction (NWP).
Ongoing PhD projects (main supervisor)
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.
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.
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.
is an industrial PhD in collaboration with the 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
PhD students (finalised 2009-2015)
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
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)
Cvijanović. Ivana studied the climate dynamics related to abrupt
climate change with main focus on potential atmospheric
Korsholm (in collaboration with DMI). Ulrik modelled the indirect
effects of aerosol. Ulrik is co-developer of the ENVIRO-HIRLAM
model at DMI.
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
(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.
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.
(planned 2016) works on physically based statistical downscaling
of extreme precipitation events in a warmer climate with special
focus on precipitation changes in the UK.
Valentin Ukkonen (planned 2016) uses information from a regional
climate model to model extreme precipitation in a warmer climate.
master theses (finalised 2008-2016)
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.
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
Eggeling (2016) analysed relationships between temperature and
the occurrence of extreme precipitation over the Brittish Isles.
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.
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.
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.
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
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.
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).
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).
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.
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)
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
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).
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).
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).
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)
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).
(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.
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)
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.
CV , four
page CV , two
page CV , one
page CV, recent
Recent reviewed scientific publications
can be delivered on request, also for accepted manuscripts):
Kaas, E., 2008: A
simple and efficient locally mass conserving semi-Lagrangian
transport scheme. Tellus,
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.
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.:
Issue 635, pp. 1583–1595,
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.
T. A. S, N. Kliem, E. Kaas (2011) The effect of climate change on
the sea ice and the hydrography in the Nares Strait.
P. L. Langen, and E. Kaas (2011): Weakened
atmospheric energy transport feedback in cold glacial climates.
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,
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:
I, P. L. Langen, E. Kaas, and Peter D. Ditlevsen (2013): Southward
Intertropical Convergence Zone shifts and implications for an
atmospheric bipolar seesaw.
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
Rathmann, N. M., S. Yang
and E. Kaas (2013): Tropical cyclones in enhanced resolution CMIP5
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
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.
Phys., 13, 7747-7764,
E., B. Sørensen, C. C. Tscherning and M. Veicherts (2013):
Multi-processing least squares collocation: Applications to
gravity field analysis. Journal
of Geodetic Science.
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.
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,
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.
A. A., F. Collins, K. A. Leonard, and E. Kaas (2016): Comparison
of Precipitable Water over Ghana using GPS Signals and Reanalysis
products. Accepted in Journal of Geodetic Science.
A. M., S. Yang, and E. Kaas (2016): Sea ice thickness and recent
Arctic warming. Geophysical Research Letters, Submitted.