Every day, ECMWF produces various global Analyses and Forecasts and archives them in MARS. The first ECMWF numerical model in 1979 was a grid-point model with 15 levels in the vertical and a horizontal resolution of 1.875 degrees in latitude and longitude, corresponding to a grid length of 200 kilometres. A number of major changes have occurred since ECMWF's activity started:
The upgrade to IFS Cycle 47r2 on 11 May 2021 increased the vertical resolution for the ensemble (ENS, streams enfo, enfh, efov, efho) NS) from 91 to 137 model levels, bringing it in-line with the HRES resolution.
- 5 Nov 2017: Implementation of Seasonal Forecast SEAS5
- With the upgrade on 22 November 2016, the medium-range ensemble and its monthly extension see a major upgrade in the dynamical ocean model (NEMO): the resolution is increased from 1° and 42 layers to 0.25° and 75 layers (ORCA025Z75). Furthermore, NEMO model version v3.4.1 with the interactive sea-ice model (LIM2) is implemented. The ocean and sea-ice components of the ENS initial conditions are provided by the new ocean analysis and reanalysis suite ORAS5, which uses the new ocean model and revised ensemble perturbation method.
- On 8 March 2016 with the introduction of cycle 41r2 the horizontal resolution was upgraded, equivalent to about 9 km for HRES and the data assimilation (the outer loop of the 4D-Var) and to about 18 km for the ENS up to day 15. The resolution of the ENS extended (day 16 up to day 46) is about 36 km. Cycle 41r2 also introduced a new reduced Gaussian grid, the octahedral grid. > Full description
- In Apr 2015 with cycle 41r1 the domain of the limited-area ocean wave model has been extended to the full globe and is now referred to as HRES-SAW. The ENS configuration has been changed and new climate files have been introduced. > Full description
In November 2013 the vertical resolution and the vertical extent used for the medium-range and monthly ensemble forecasts has changed: the number of levels of the ENS has increased from 62 to 91 with the model top raised from 5 hPa to 0.01 hPa. The MARS streams DCDA, DCWV, ENDA and EWDA were discontinued.
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