Om mig

 

Jag är biträdande lektor i beräkningsteknik med applikationer i klimatvetenskap. Min forskning handlar främst om hur numeriska metoder ska användas på bästa sätt i klimatmodeller. Mina specifika forskningsintressen inkluderar bland annat utveckling och analys av finita element metoder, inlandsismodellering, modell-adaptivitet, och mer nyligen havsmodellering och stokastiska processer. Jag har även intresse av perturbations-teori och radiella-basfunktion-metoder. 

För en översiktlig introduktion om vad min forskning på beräkningsteknik inom inlandsismodellering handlar om, läs gärna denna populärvetenskapliga artikel i studentmagasinet XRDS: Crossroads, the ACM Magazine for Students. 

Jag har tidigare arbetat som postdoktor vid matematiska institutionen på Christian-Albrechts-Universität i Kiel, Tyskland, och som doktorand vid IT-institutionen på Uppsala Universitet. 

Undervisning

I vår kommer jag att undervisa programmeringsdelen av kursen Geometri och programmering för lärare i matematik

Forskning

Publikationer

 

• Ahlkrona, J., Braack, M., "Equal-Order Stabilized Finite Element Approximation of the p-Stokes Equations on Anisotropic Cartesian Meshes", Computational Methods in Applied Mathematics, 2019

• Ahlkrona, J. "How much are the Greenland and Antarctic Ice Sheets Melting?", XRDS: Crossroads, The ACM Magazine for Students, 2018

• Helanow, C., Ahlkrona, J.,  "Stabilized equal low-order finite elements in ice sheet modeling – accuracy and robustness", Computational Geosciences, 2018

• Ahlkrona, J., Shcherbakov, V.,  "A Meshfree Approach to Non-Newtonian Free Surface Ice Flow: Application to the Haut Glacier d'Arolla'', Journal of Computational Physics, 2017

• Ahlkrona, J., "Computational Ice Sheet Dynamics- Error control and efficiency", PhD-thesis (2016)

• Ahlkrona, J., ''The ISCAL method and the Grounding Line - Combining the Stokes equations with the Shallow Ice Approximation and Shelfy Stream Approximation'', Technical Report 2016-006 Uppsala University, 2016

• Ahlkrona, J., Lötstedt, P., Kirchner, N., Zwinger, T., ''Dynamically coupling the non-linear Stokes equations with the Shallow Ice Approximation in glaciology: Description and first applications of the ISCAL method'', Journal of Computational Physics, 2016

• Kirchner, N., Ahlkrona, J., Lötstedt, P., Gowan, E., Lea, J., Noormets, R., von Sydow, L., Dowdeswell J., Shallow Ice Approximation, Second Order Shallow Ice Approximation, and Full Stokes models: a discussion of their roles in palaeo-ice sheet modelling and development, Quaternary Science Reviews, 2016

• Ahlkrona, J., Kirchner, N., Lötstedt, P., ''Accuracy of the zeroth and second order shallow ice approximation - numerical and theoretical results'', Geoscientific Model Development, 2013

• Ahlkrona, J., Kirchner, N., Lötstedt, P., "A Numerical Study of Scaling Relations for Non-Newtonian Thin-film Flows with Applications in Ice Sheet Modelling'', Quarterly Journal Of Mechanics And Applied Mathematics, 2013

• Ahlkrona, J., ''Implementing Higher Order Dynamics into the Ice Sheet Model SICOPOLIS'', Master's Thesis with Nina Kirchner (supervisor) and Per Lötstedt (reviewer), 2011.

Föredrag

• The Numerical (in?)Stability of Ice Sheet Models, Seminar at the Division of Scientific Computing, Uppsala University, 2018
• Local Projection Stabilization of the p-Stokes Equations - Motivated by Ice Sheet Modelling,  Seminar at the Division of Numerical Analysis, Mathematics, Royal Institute of Technology, Stockholm 2017
• Finite Element Discretization of the p-Stokes Equations for Glaciological Applications, at the workshop "Numerical Methods for PDEs and their applications", Mittag-Leffler Institut, Stockholm 2017 
• The Impact of Ice Sheet Melting on the Ocean – Reducing Uncertainty in Predictions of Future Sea-Level Rise and Ocean Circulation by Improving Computer Models, Arctic Circle Assembly, 2017
• Towards stable ice sheet simulations – Inf-sup stabilization of the p-Stokes equations on anisotropic meshes, SIAM Conference on Mathematical and Computational Issues in the Geosciences, Erlangen, 2017
• Local projection stabilization for the p-Stokes equations, 12th International Workshop on Variational Multiscale and Stabilized Finite Elements, Sevilla, 2017
• The p-Stokes equation with glaciological applications, CSE workshop 2017, Plön, 2017
• Ice Sheet Modelling ISCAL (Ice Sheet Coupled Approximation Levels) - Dynamically Coupling the Non-linear Stokes Equations with the Shallow Ice Approximation - European Numerical Mathematics and Advanced Applications, Ankara, September 2015
• ISCAL (Ice Sheet Coupled Approximation Levels) - an Ice Sheet Model applied in the FROZEN-project - SIAM Conference on Mathematical and Computational Issues in the Geosciences, Stanford, June 2015
• The Fast Full Stokes Method (FFS) Applied to the Greenland Ice Sheet - International Symposium on Contribution of Glaciers and Ice Sheets to Sea Level Change, Chamonix, May 2014.
• Fast Full Stokes (FFS) - Dynamic Coupling of the SIA and full Stokes Equations - American Geophysical Union Fall Meeting 2013, San Francisco, December 2013.
• Improving paleosimulations of Ice Sheet/Ice Stream/Ice Shelf Systems: The development of a Fast Full Stokes numerical ice code, and first applications - Bolin Days 2013 - Stockholm University, November 2013.
• The Second-Order Shallow Ice Approximation - Workshop in Ice Modeling and Simulation, Division of Scientific Computing, Uppsala University, February 2012.
• Ice Sheet Modeling - Improving the Modeling of Ice Dynamics - Seminar at the Department of Numerical Analysis, The Royal Institute of Technology KTH, April 2011.
• Ice Streams in the Past, the Present and the Future: A Challenge for Numerical Modeling - Annual Meeting of the Bert Bolin Centre for Climate Research, Stockholm, November 2010.
• Updating the ice sheet model SICOPOLIS with an improved treatment of ice flow - International Glaciological Society Nordic Branch Meeting 2010, Copenhagen, October 2010.
• Implementing Second Order Equations into SICOPOLIS - Seminar at the Department of Physical Geography and Quaternary Geology, Stockholm University, October 2010.