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NEWS!
Information on meteorological impact A giving Changes the Recording the and the are 1000pagePin4Meteorological content
Assimilation
- New RTTOV coefficients for hyperspectral infrared (IR) sounders
- New height reassignment for low level AMVs
- Add representativeness error in the total observation error for Aeolus
- Weak-constraint 4D-Var active in the stratosphere for the EDA system
Observations
- Assimilation of all-sky AMSU-A
Model
- A more consistent formulation of boundary layer turbulence, shallow convection and sub-grid cloud including:
- Simplified and more consistent treatment of sub-grid cloud saturation adjustment
- Consistent treatment of subgrid cloud from boundary layer turbulent mixing without separate statistical cloud scheme
- Consistent computation of mixing height for unstable turbulent boundary layer and convection scheme
- Change from double to single iteration of turbulent mixing scheme
- New method for computing inversion strength based on moist entropy for distinguishing stratocumulus and cumulus cloud
- Limit to convective overshoot based on tropopause stability
- New parametrized deep convection closure with an additional dependence on total advective moisture convergence
- Change from exponential-exponential cloud vertical overlap to random-exponential overlap in closer agreement with observations
- Include vapour deposition process for growth of falling snow particles
- Change from linear to cubic interpolation for cloud liquid, ice, rain and snow semi-Lagrangian departure point calculations, including 3D quasi-monotone limiter
- Interpolation of cloud and precipitation to radiation grid changed from in-cloud to grid-mean
- Inclusion of full supersaturation adjustment in the ensemble SPPT stochastic perturbations
- Mass-weighting and relaxation timescale introduced for ensemble SPPT stochastic perturbations
- Revised simplified moist physics and associated tangent-linear and adjoint
- Bug fix for vertical interpolation of 3D aerosol climatology
- Improved calculation of extinction coefficients for near-surface visibility in fog, rain and snow
- Revised gustiness parametrization
- Improved calculation of the peak wave period for multi-peaked ocean wave spectra
Meteorological impact
- Extratropical upper-air geopotential and wind in the first few days of the forecast improved by a few percent
- Tropical upper-air winds throughout the medium-range improved by up to 7%, reducing with lead time
- Tropical upper-air temperature improved in HRES, but degraded CRPS in ENS due to small (~0.2K) increase in bias. Low level temperatures (including 850hPa and 2m) temperature approximately neutral versus observations but degraded versus analysis over subtropical ocean.
- Tropical Cyclones: 10% improvement in position error in HRES and ENS and weaker central pressure
- Improved MJO prediction and amplitude
- More realistic precipitation PDF in strongly convective regimes
- Increased convective precipitation (reduced dry bias) in arid regions
- Increase in small scale structure for cloud and precipitation but total cloud cover degraded
- Reduced biases for wind gusts and for visibility in fog, rain and snow
The separate document 47r3 Impact on Surface Weather representation highlights the changes with 47r3 in the characteristics of many frequently used forecast fields and products.
Evaluation
Scorecards presenting the new cycle performance are regularly updated:New and changed parameters
New parameters
The table contains the list of parameters expected to be available with the model implementation. They will be available as part of the test data.
ENS CF/PF
Correct decoding of all 47r3 GRIB 2 parameters requires ecCodes 2.23.0 or newer. Users are encouraged to check their data processing with the test data provided.
Software
The software packages listed below are required to provide full support for IFS Cycle 47r3 and will become the default on ECMWF platforms on Wednesday 6 October 2021, see Change of default versions of ECMWF software packages - October 2021:
ecCodes 2.23.0
Magics 4.9.0
Metview 5.13
CDO 1.9.10-01
Users are strongly encouraged to test their software applications and data processing chain with the new versions of the various software packages before this change.
Availability of 47r3 test data
Test data in MARS
IFS Cycle 47r3 beta test data is available from MARS with experiment version 0076 (MARS keyword EXPVER=0076):
- HRES (class=od, stream=oper, expver=76)
- HRES-WAM (class=od, stream=wave, expver=76)
- ENS (class=od, stream=enfo, expver=76)
- ENS-WAM (class=od, stream=waef, expver=76)
Only users registered with access to MARS will be able to access these test data sets. The data should not be used for operational forecasting. Please report any problems you find with this data via the ECMWF Support Portal.
The release candidate test data and products, available from , will be note, pp. 24-32. DOI:10.21957/3gt59vx1pbDavid Duncan et al., Assimilation of AMSU-A in all-sky conditions. EUMETSAT/ECMWF Fellowship Programme Research Report, in preparation, 2021