Ulrich Achatz

TL;DR: In this article, the authors make a case that the use of stochastic representation of unresolved processes in the atmosphere, oceans, land surface, and cryosphere of comprehensive weather and climate models gives rise to more reliable probabilistic forecasts of weather, and reduces systematic model bias.

TL;DR: In this article, the authors highlight recent developments from different research groups which show that the stochastic representation of unresolved processes in the atmosphere, oceans, land surface and cryosphere of comprehensive weather and climate models (a) gives rise to more reliable probabilistic forecasts of weather, and (b) reduces systematic model bias.

TL;DR: In this paper, the authors provided a scale analysis showing that the regime of validity of two of these extended models covers stratification strengths on the order of (hsc/u)du/dz, M 2/3, which corresponds to realistic variations of potential temperature u across the pressure scale height hsc of Duj h sc 0,30K.

TL;DR: In this paper, a semi-empirical model of atmospheric dynamics is presented, which is based on a Lorenz-type filtered two-layer model, but its linear terms are replaced by an empirically determined operator.

TL;DR: In this article, a quasi-linear theory for the acceleration rates and propagation parameters of charged test particles in weakly turbulent electromagnetic plasmas is considered. And the similarity between two recent approaches to modelling of therandom electromagnetic field is demonstrated.