The TRR 181 seminar is held by Serhat Can (Leibniz Institute for Atmospheric Physics, PhD in T1) on May 16, 11 am at Universität Hamburg, Bundesstr. 53, room 22/23.
“Investigation of Mesoscale Energy Cascades with a Scale Invariant GCM”
Attempts to explain the different parts of observed tropospheric Kinetic Energy (KE) spectra historically focused on different driving mechanisms. Although the synoptic and larger scales could be explained with Geostrophic turbulence, leading to an inverse energy cascade for planetary scales and a forward enstrophy cascade in the synoptic regime, theories for the mesoscales are largely exempt from such a consensus.
In the present study, we review the dynamics for the high wavenumber regime of a GCM from the perspective of Stratified Macro Turbulence (SMT), and we look for conditions for the existence of SMT via analyzing the spectral budget of KE. We argue that a net forward energy cascade for wavenumbers beyond the kink seen in spectral slopes is governed by SMT. Analysis is carried out on a 12 day time series from a January simulation performed with Kühlungsborn Mechanistic Circulation Model with idealized differential heating. Different contributions to the KE budget are compared between runs having different diffusion schemes in the momentum equation.