The large-scale kinetic energy (KE) spectrum is fairly well represented in current General Circulation Models (GCMs) and data assimilation products. Although the meso-scale KE spectrum in the tropopause region is fairly well constrained from aircraft measurements, models are just beginning to resolve this scale now. In particular, observations show a shallowing of the slope of the spectrum in the meso-scale, which has been replicated in some free-running GCMs and regional models.
In this talk I will give an overview of the representation of the KE spectrum in high resolution operational analysis from the European Centre for Medium- Range Weather Forecasts. Consistent with observations, spectral shallowing in the meso-scale is evident in the data, beginning in the lower stratosphere and becoming more pronounced with altitude. I will discuss the meso-scale KE cascade and possible mechanisms that can lead to the observed spectral shallowing.