Modal decomposition of ECMWF deterministic forecasts

 

Atmospheric energy spectra

Distribution of atmospheric balanced and inertia-gravity energy as a function of the zonal wavenumber.
 

Circulation maps

Horizontal circulation maps of the Northern and Southeren Hemisphere and the Tropics.
 

Tropical winds

Longitude-altitude diagram of the tropical zonal winds associated with the balanced and inertio-gravity circulation and the equatorial Kelvin wave.
 

Hovmoeller diagrams

Ten-day evolution of the tropical winds on selected levels.
 

Kelvin waves

Evolution of the Kelvin wave in the ECMWF model forecast and comparison with analyses.
 

Mixed Rossby-gravity waves

Mixed Rossby-gravity waves in the ECMWF model.
 

Polar maps

Polar maps of horizontal winds in the Northern Hemisphere (40°N-90°N)

 

n=1 Rossby waves

n=1 Rossby wave horizontal winds and geopotential height (60°S-60°N)
 

Inertia-gravity waves

Horizontal winds and geopotential height perturbations associated with eastward and westward inertia-gravity waves (40°S-40°N)

Modal view of atmospheric circulation

representation of the atmosphere

MODES applies three-dimensional linear wave theory for the decomposition of global circulation in terms of normal-mode functions (NMFs). For details, see https://gmd.copernicus.org/articles/8/1169/2015/. MODES outputs quantify spatial and temporal variability associated with the two main circulation regimes, the Rossby wave (or balanced) regime and the inertia-gravity wave (or unbalanced) regime. The approach is most useful in the tropics where the two special NMF solutions, the Kelvin wave and the mixed Rossby-gravity wave, account for a significant part of tropical variability. Recently published book describes theory and applications of normal-mode functions in weather and climate dynamics and numerical weather prediction research: https://www.springer.com/gp/book/9783030609627. MODES pages provide real-time and archive results of modal decomposition of the operational deterministic ECMWF 10-day forecasts. Selected outputs of modal analysis of reanalysis and interesting datasets are also here.

MODES is maintained and further developed by the Atmospheric Dynamics and Predictability group of Prof. Nedjeljka Žagar at the University of Hamburg.