Description of the upgrade

Datasets affected

• HRES
• ENS

Resolution

Unchanged

Meteorological content

• Five-species prognostic microphysics scheme, introducing cloud rain water content, and cloud ice water content as new model variables.
• Retuning and simplification of convective entrainment/detrainment and land/sea dependent threshold for precipitation
• Retuning of subgrid-scale orographic gravity wave drag
• Adjustment to diffusion in stable boundary Iayers near the surface
• All-sky improvements of microwave radiance assimilation
• Adaptation to neutral wind of the observation operator for scatterometer data
• New soil-moisture analysis scheme (SEKF, simplified ensemble Kalman filter)
• New snow analysis based on 0I (Optimum Interpolation), and upgrade of NESDIS snow cover data to 4 km resolution.
• Monthly varying climatology of leaf area index (LAI) based on MODIS data
• The 4D-Var of the Early Delivery suite performs 2 rather than 3 updates of the outer loop

• Revision of stochastically perturbed physical tendencies
• Introduction of spectral stochastic backscatter scheme
• Retuned initial perturbation amplitudes

Meteorological impact

• Benefit in terms of objective scores in the medium range in both hemispheres, particularly in the upper troposphere.
• positive verification for winds against observations, whereas verification against analyses tends to be negative in the shorter range, which can be explained by higher variability in the analysed wind fields.
• improved snow analysis issues that affected the analysed snow depth on the 2009/2010 winter
• modifications to the stable boundary layer improve the diurnal cycle of 2m temperature, especially some reduction of the night-time cold bias over Europe
• improved tropospheric humidity analysis

• improved probabilistic scores in the extra-tropics
• better tuned spread-skill relationship - especially for 500 hPa geopotential height in the earlier forecast ranges (days 1-5)

New and changed parameters

New parameters

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Resources

ECMWF Newsletter: See Newsletter 126