6 papers
Diffusive behavior of transport noise on
Sagy Ephrati, Erik Jansson, Andrea Papini
We investigate theoretically and numerically transport noise-induced diffusion in flows on the sphere. Previous analysis on the torus demonstrated that suitably chosen transport no…
Trajectory learning for ensemble forecasts via the continuous ranked probability score: a Lorenz '96 case study
Sagy Ephrati, James Woodfield
This paper demonstrates the feasibility of trajectory learning for ensemble forecasts by employing the continuous ranked probability score (CRPS) as a loss function. Using the two-…
Thermal quasi-geostrophic model on the sphere: derivation and structure-preserving simulation
Michael Roop, Sagy Ephrati
We derive the global model of thermal quasi-geostrophy on the sphere via asymptotic expansion of the thermal rotating shallow water equations. The model does not rely on the asympt…
On spectral scaling laws for averaged turbulence on the sphere
Sagy Ephrati, Erik Jansson, Klas Modin
Spectral analysis for a class of Lagrangian-averaged Navier--Stokes (LANS) equations on the sphere is carried out. The equations arise from the Navier--Stokes equations by applying…
Critical latitude in global quasi-geostrophic flow on a rotating sphere
Arnout Franken, Erwin Luesink, Sagy Ephrati +1
In this paper, we study geostrophic turbulence without external forcing or dissipation, using a Casimir-preserving numerical method. The research examines the formation of large zo…
Casimir preserving numerical method for global multilayer geostrophic turbulence
Arnout Franken, Erwin Luesink, Sagy Ephrati +1
Accurate long-term predictions of large-scale flow features on planets are crucial for understanding global atmospheric and oceanic systems, necessitating the development of numeri…