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 in the following semester (block) courses:
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.
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
Thorn Ljungdal investigates the possibilities of using remote
sensing data to determine the extend, thickness and type of snow
on sea ice (focus on Arctic sea ice). In collaboration with Leif
Toudal at DMI.
works on a new explicit filter for stabilising non-hydrostatic
models based on the fully compressible Euler equations. This is
an alternative to the use of (semi-)implicit discretisation.
Michael Lang works on the impact of Sea ice thickness in the
Arctic. Andreas is modifying 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.
works on physically based statistical downscaling of extreme
precipitation events in a warmer climate with special focus on
precipitation changes in NW Europe.
Eggeling works on present and future change in precipitation
statistics/extremes over the Brittish Isles.
Honsinger studies possible changes of large scale climate
variability in a warmer climate. In collaboration with Shuting
Yang at DMI.
Valentin Ukkonen will use information from a regional climate
model to model extreme precipitation in a warmer climate.
master theses (finalised 2008-2015)
Hintz assimilated (nudge) high resolution precipitation radar
data information into the HIRLAM system at DMI aiming at improved
short term forecasts of heavy precipitation (“Nowcasting”).
His special focus was on the importance of the length of the time
step required to resolve intensive convection. In collaboration
Ademola Kayode 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.