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title17-08-2011 CMC

The CMC global ensemble prediction system was upgraded to version 2.0.2 on 17 August 2011.

The main changes included in this upgrade are:

  • The number of members in the ensemble Kalman filter is doubled from 96 to 192.
  • The resolution of the medium-range forecasts is changed from 100 to 66 km.
  • The model top is raised from 10 hPa to 2 hPa.
  • A new dynamical model, with a Charney-Phillips vertical grid, is used.

Further documentation of the operational upgrade can be found at http://collaboration.cmc.ec.gc.ca/cmc/CMOI/product_guide/docs/changes_e.html

ECMWF

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title1106-0706-2017 2018 ECMWF

The ECMWF forecast system IFS was upgraded to the version 43r345r1.

The main changes included in this upgrade:

Assimilation

  • Weakly coupled sea-ice atmosphere assimilation applied with the use of OCEAN5 sea-ice (instead of OSTIA) in the surface analysis of the high-resolution (HRES 4d-Var) and the ensemble of data assimilations (EDA) analyses;
  • Relative humidity increments calculated using temperature instead of virtual temperature;
  • Weak constraint model error forcing applied at every time step instead of every hour to avoid shocks in the model integration.

Observations

  • 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-dimensional ocean and atmosphere: introduction of the coupling to the NEMO 3-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;

Click  here for full details.


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title11-07-2017 ECMWF

The ECMWF forecast system IFS was upgraded to the version 43r3In this upgrade there are many scientific contributions, including changes in data assimilation (both in the EDA and the 4DVAR), in the use of observations, and in modelling. The new cycle only includes meteorological changes; there are no technical changes, e.g. new resolutions.

The main changes included in this upgrade:

Assimilation

    • Improved humidity background error variances directly from the EDA like for all other variables.
    • Revised wavelet filtering of background error variances and revised quality control of drop-sonde wind observations in 4DVAR to improve tropical cyclone structures.

Observations

    • Increased use of microwave humidity sounding data by adding new sensors (SAPHIR, GMI 183 GHz channels).
    • Activation of 118 GHz channels over land from MWHS-2 instrument on-board FY-3C.
    • Harmonised data usage over land and sea-ice for microwave sounders (adding MHS channel 4 over snow, adding some ATMS channels, lower observation errors for MHS data over land).
    • Improved screening of infrared observations for anomalously high atmospheric concentrations of hydrogen cyanide (HCN) from wildfires.
    • Improved quality control for radio occultation observations and radiosonde data.

Model

    • New, more efficient radiation scheme with reduced noise and more accurate longwave radiation transfer calculation.
    • New aerosol climatology based on ‘tuned’ CAMS aerosol re-analysis including dependence on relative humidity.
    • Increased super-cooled liquid water at colder temperatures (down to -38C) from the convection scheme.
    • Visibility calculation changed to use ‘tuned’ CAMS aerosol climatology.

Click  here for full details.

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