Vorticity-Divergence semi-Lagrangian Global Atmospheric Model
SL-AV20: Dynamical Core
Mikhail Tolstykh1,2,3, Vladimir Shashkin1, Rostislav Fadeev1,3, and Gordey Goyman3,11Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russia 2Hydrometeorological Centre of Russia, Moscow, Russia 3Moscow Institute of Physics and Technology (State University), Moscow, Russia
Received: 11 Oct 2016 – Accepted for review: 08 Dec 2016 – Discussion started: 12 Dec 2016
Abstract. SL-AV (Semi-Lagranginan Absolute Vorticity) is a global atmospheric model. Its latest version SL-AV20 provides global operational medium-range weather forecast with 20 km resolution over Russia. The lower resolution configurations of SL-AV20 are being tested for seasonal prediction and climate modeling.
The article presents the model dynamical core. Its main features are vorticity-divergence formulation at the unstaggered grid, high-order finite-difference approximations, semi-Lagrangian semi-implicit discretization and the reduced latitude-longitude grid with variable resolution in latitude.
The accuracy of SL-AV20 numerical solutions using reduced lat-lon grid and the variable resolution in latitude is tested with two idealized testcases. The results agree well with other published model solutions. It is shown that the use of the reduced grid having up to 25 % less grid points than the regular grid does not significantly affect the accuracy. Variable resolution in latitude allows to improve the accuracy of solution in the region of interest.
Tolstykh, M., Shashkin, V., Fadeev, R., and Goyman, G.: Vorticity-Divergence semi-Lagrangian Global Atmospheric Model
SL-AV20: Dynamical Core, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2016-265, in review, 2016.