Virtual Event: Annual Seminar 2020

Consistent Modelling of Non-Equilibrium Thermodynamic Processes in the Atmosphere

Authors: Paul Bowen, John Thuburn
Presenting Author: Paul Bowen

Approximations in the moist thermodynamics of atmospheric/weather models are often inconsistent. Different parts of numerical models may handle the thermodynamics in different ways, or the approximations may disagree with the laws of...

Currently, the dynamical core of Russian operational global NWP model is the hydrostatic semi-Lagrangian semi-implicit core SLAV20 (Tolstykh et al, GMD 2017). The operational version has the horizontal resolution about 20 km. The new version with 10 km resolution is under testing. The works on increase of parallel efficiency for this new version of SLAV model are presented. The result is 23%...

The dynamical core of the Global Environment Multiscale (GEM) model—used operationally by Environment and Climate Change Canada (ECCC)—is based on a log-hydrostatic-pressure-type terrain-following coordinate (TFC) in the vertical. Recently, a new dynamical core for the GEM model has been developed that introduces the option of a height-based TFC. Hereinafter, the new core is referred to as...

In the simulation of complex multi-scale flow problems, such as those arising in weather and climate modelling, one of the biggest challenges is to satisfy operational requirements in terms of time-to-solution and available energy without compromising the accuracy and stability of the solution. These competing factors require extreme computational capabilities in conjunction with...

Eddy-permitting numerical ocean models resolve mesoscale turbulence only partly, that leads to underestimation of eddy kinetic energy (EKE). Mesoscale dynamics can be amplified by using kinetic energy
backscatter (KEB) parameterizations returning energy from the unresolved scales. We consider two types of KEB: stochastic and negative viscosity ones. The tuning of their amplitudes is based on a...

The Met Office is currently developing a next generation dynamical core for weather and climate prediction, known as GungHo. The model uses compatible finite-elements with finite-volume methods for the transport and is designed to be highly scalable and easily adaptable to future supercomputing architectures. A limited-area version of the model is also being developed: a limited-area model...

The upcoming era of exascale computing promises significant improvements in model resolution and thus forecasting skill for numerical weather codes. However, all known or presumed candidates for exascale supercomputers are going to feature novel computing hardware or heterogeneous architectures. Using these machines efficiently with today's complex operational weather prediction codes requires...

In a NWP model a prognostic equation is being solved (simplified):
\begin{equation}
\frac{\partial\psi}{\partial t} + u \frac{\partial\psi}{\partial x}=L+N+P
\end{equation}
where l is the linear part of the dynamics contribution, N is the non-linear part from dynamics and P is the physics tendency.

In a semi-implicit semi-lagrangian treatment, the future value of the variable is...

The discontinuous Galerkin (DG) method is, by now, a well established numerical method
in nearly all areas of computational and geophysical fluid dynamics. In addition to the
ability to use high-order approximation spaces, its robustness for problems with shocks
and discontinuities and its natural support for h- and p-adaptivity count as the main
strengths. However, a persistent issue of...