Grave wave (GW) parameterisations currently used in state-of-the-art weather and climate models are based on a purely columnar approach, which does not allow for any horizontal propagation of GWs and has been identified as potential source of systematic biases in the simulation of middle atmospheric dynamics. The study by Eichinger and colleagues presents now a computationally efficient method to emulate the effects of lateral propagation of orographic GWs in climate models by horizontal momentum flux redistribution using redistribution maps derived from a GW ray-tracing model. The presented approach is an important step towards a better representation of orographic GWs in climate models, which might improve long-standing problems in atmospheric modelling.
Grave wave (GW) parameterisations currently used in state-of-the-art weather and climate models...
The columnar approach of gravity wave (GW) schemes results in dynamical model biases, but parallel decomposition makes horizontal GW propagation computationally unfeasible. In the global model EMAC, we approximate it by GW redistribution at one altitude using tailor-made redistribution maps generated with a ray tracer. More spread-out GW drag helps reconcile the model with observations and close the 60°S GW gap. Polar vortex dynamics are improved, enhancing climate model credibility.
The columnar approach of gravity wave (GW) schemes results in dynamical model biases, but...