A new dynamical core for NWP based on the spectral element method is presented. In this work, the 3D primitive hydrostatic atmospheric equations are written, discretized, and solve in 3D Cartesian space. The advantages of this approach are: the pole singularity which plagues all gridpoint methods disappears, the horizontal operators can be approximated by local high-order elements, and any grid can be used including lat-lon, icosahedral, hexahedral, and adaptive unstructured grids. The locality property of spectral elements means that the method will scale efficiently on distributed-memory computers. In order to validate our 3D atmospheric dynamical core,

we have run three test cases: Rossby-Haurwitz waves 1 and 4, and the Held-Suarez test case. Comparisons with the Navy's operational NWP model (NOGAPS) using the Rossby-Haurwitz waves demonstrate the high-order accuracy of the solutions obtained with our new model. The model is shown to scale quite well on distributed-memory computers.

[1] F.X. Giraldo, A spectral element shallow water model on spherical geodesic grids, International Journal for Numerical Methods in Fluids, Vol. 35, 869-901 (2001).