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- Assimilation of non-surface-sensitive infra-red (IR) channels over land;
- Assimilation of all sky micro-wave (MW) sounding channels over coasts;
- Use of direct broadcast FY-3C MWHS2 data for better timeliness;
- Introduction of RTTOV-12 and new microwave instrument coefficients;
- Activation of constrained variational bias correction (VarBC);
Retuning of the radiosonde observation error, and introduction of a scheme to account for radiosonde drift;
Introduction of temperature bias correction of old-style AIREP observations; aircraft temperature varBC predictor upgraded to a three predictor model (cruise, ascent, descent); reduced thinning of aircraft data;
Assimilation of JASON-3 and Sentinel-3A altimeters, and use of new altimeters for wave data assimilation;
Model
- Coupling of the 3-dimentional dimensional ocean and atmosphere: introduction of the coupling to the NEMO 3-dimentional dimensional ocean model also in the high-resolution forecast (HRES), with the same ocean model version used in the medium-range/monthly ensemble (ENS): NEMO3.4 in ORCA025_Z75 configuration; upgrade of the NEMO-IFS coupling strategy in both ENS and HRES to a full-coupling in the tropical region (partial-coupling-extra-tropics);
- Improved numerics for warm-rain cloud microphysics and vertical extrapolation for semi-lagrangian trajectory;
- Increased methane oxidation rate to improve (increase) water vapour in the stratosphere;
- Improved representation of super-cooled liquid water in convection, and minor convection updates;
- Improvements in the tangent forward and adjoint models linked to the convection scheme;
- Correction of soil thermal conductivity formulation and addition of soil ice dependency;
- New extended output parameters have been added. See below.
- Modified parameter for non-orographic gravity-wave drag scheme for 91 levels;
- Model error changes:
- Stochastically perturbed parametrization tendency scheme (SPPT): improved flow-dependent error representation via reduced spread in clear skies regions (due to unperturbed radiative-tendency in clear sky), activation of tendency perturbations in stratosphere, and weaker tapering of perturbations in boundary layer; amplitude reduction of the SPPT perturbations patterns (by 20%);
- EDA: cycling of stochastic physics random fields in the EDA, and adoption of the same SPPT configuration in EDA as in ENS;
- Stochastic kinetic energy backscatter scheme (SKEB): deactivation of the stochastic backscatter (SKEB) scheme due to improved model error representation by the SPPT scheme (see above), leading to a 2.5% cost saving in the ENS;
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