- Large scale atmospheric dynamics (balanced dynamics, potential vorticity inversion, wave-vortex interactions, dynamics of middle-latitude storm tracks, etc.)
- Numerical methods for fluid flows (the application of contour-advective methods to models of the Atmosphere and Ocean, Optimal algorithms for wave-vortex interaction problems, numerical weather prediction)

- Dritschel, D.G., Polvani, L.M. & Mohebalhojeh, A.R.

The contour-advective semi-Lagrangian algorithm for the shallow water equations.*Mon. Wea. Rev.***127(7)**, 1151-1165 (1999).

- Mohebalhojeh, A.R. & Dritschel, D.G.

On the representation of gravity waves in numerical models of the shallow water equations.*Q. J. Roy. Meteorol. Soc.***126****, 669-688 (2000).**

**Mohebalhojeh, A.R. & Dritschel, D.G.**

Hierarchies of balance conditions for the*f*-plane shallow water equations.*J. Atmos. Sci.*,**58****, 2411-2426 (2001).**

**Mohebalhojeh, A.R.**

On shallow water potential vorticity inversion by Rossby-number expansions.*Q. J. Roy. Meteorol. Soc.***128****, 679-694 (2002).**

**Mohebalhojeh, A.R. & Dritschel, D. G.**

Contour-advective semi-Lagrangian algorithms for many-layer primitive equation models.*Q. J. Roy. Meteorol. Soc.***130****, 347-364 (2004).**

**Esfahanian, V., Ghader, S., & Mohebalhojeh, A. R.**

On the use of super compact scheme for spatial differencing in numerical models of the atmosphere.*Q. J. Roy. Meteorol. Soc.***131****, 2109-2129 (2005).**

**Mohebalhojeh, A.R. & McIntyre, M.E.**

Local mass conservation and velocity splitting in PV-based balanced models. Part I: The hyperbalance equations.*J. Atmos. Sci.***64****, 1782-1793 (2007).**

**Mohebalhojeh, A.R. & McIntyre, M.E.**

Local mass conservation and velocity splitting in PV-based balanced models. Part II: Numerical results.*J. Atmos. Sci.***64****, 1794-1810 (2007).**

**Mohebalhojeh, A.R. & Dritschel, D. G.**

Assessing the numerical accuracy of complex spherical shallow water flows.*Mon. Wea. Rev.***135****, 3876-3894 (2007).**

**Ghader, S. Mohebalhojeh, A.R. & Esfahanian, V.**

On the spectral convergence of the supercompact finite-difference schemes for the*f*-plane shallow-water equations.*Mon. Wea. Rev.***137****, 2393-2406 (2009).**

**Mohebalhojeh, A.R. & Dritschel, D. G.**

The diabatic contour advective semi-Lagrangian algorithms for the spherical shallow water equations.*Mon. Wea. Rev.***137****, 2979-2994 (2009).**

**Mohebalhojeh, A.R.**

On the momentum equation for the quasi-geostrophic model.*Q. J. Roy. Meteorol. Soc.***135****, 1638-1641 (2009).**

**Theiss, J. & Mohebalhojeh, A.R.**

The equatorial counterpart of the quasigeostrophic model.*J. Fluid. Mech.***637****, 327-356 (2009) .**

**MirRokni, S.M., Mohebalhojeh, A.R. & Dritschel, D.G.**

Revisiting vacillations in shallow-water models of the stratosphere using potential-vorticity-based numerical algorithms.*J. Atmos. Sci.*,**68****, 1007-1022 (2011).**

**Nasr-Esfahani, M., Ahmadi-Givi, F. & Mohebalhojeh, A.R.**

An energetic view of the relation between the Mediterranean storm track and the North Atlantic Oscillation .*Q. J. Roy. Meteorol. Soc.***137****, 749-756 (2011).**

**Mohebalhojeh, A.R. & Theiss J.**

The assessment of the equatorial counterpart of the quasi-geostrophic model.*Q. J. Roy. Meteorol. Soc.***137****, 1327-1339 (2011).**

**Mirzaei, M., Mohebalhojeh, A. R. & Ahmadi-Givi, F.**

On imbalance generated by vortical flows in a two-layer spherical Boussinesq primitive equation model.*J. Atmos. Sci.***69****, 2819-2834 (2012).**

- Dritschel, D.G. & Mohebalhojeh, A.R.

The contour-advective semi-Lagrangian algorithm: keeping the balance. in Proceedings of ECMWF Workshop on*Developments in numerical methods for very high resolution global models*, 5-7 June 2000, 119-136.

- Mohebalhojeh, A.R.

Waves and vortices in numerical models of the atmosphere and oceans. in Proceedings of the 9th Asian Congress of Fluid Mechanics, 27--31 May 2002, IUT, Isfahan, Iran.

- Esfahanian, V., Ghader, S., & Mohebalhojeh, A.R.

Super compact spatial differencing for the linear and nonlinear geophysical fluid dynamics problems. in Proceedings of the Third International Conference on*Computational Fluid Dynamics, ICCFD3,*, Toronto, 12-16 July 2004, 423-428.

- Mohebalhojeh, A.R. & McIntyre, M.E.

Local mass conservation and velocity splitting in potential vorticity based balanced models: The hyperbalance equations. British Applied Mathematics Colloquium 2006, Keele University, 24-27 April 2006.

- Mohebalhojeh, A.R. & Dritschel, D.G.

Contour-advective semi-Lagrangian algorithms for the spherical shallow water equations. The 2006 Workshop on the Solution of Partial Differential Equations on the Sphere , Monterey, California, 26-29 June 2006.

- A movie of
polar vortex
simulated using diabatic CASL algorithm
developed in the Vortex Dynamics group. This simulation is for 1000 days
with a strong topographic forcing of 3000m and a thermal relaxation time of
10 days using 128x128 points in longitudinal and latitudinal directions.

- See the movie of the polar vortex for 1000 days obtained at a
higher resolution of
256x256
points . For contrast, see the 1000-day
pure semi-Lagrangian solution with the same topographic forcing and
thermal relaxation.