Model upgrades

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

The ECMWF model was upgraded to cycle 36r1 on 26 January 2010.

The main changes included in this cycle are:

• Deterministic forecast and analysis horizontal resolution is increased from T799 to T1279, i.e. from 25 km to 16 km.
• EPS resolutions are increased from T399/T255 to T639/T319 for Leg A/B respectively. That is to say, the first 10 days of the EPS (Leg A) will run at T639 (32 km) and the extension beyond day 10 (Leg B) will run at T319 (63 km).
• Correction of short-wave radiation interaction with clouds.

The ECMWF model was upgraded to cycle 33r2 on 30th September 2008 12Z. The main changes included in this cycle are:

• The OSTIA (Operational Sea Surface Temperature and Sea Ice Analysis) high-resolution sea surface temperature, produced by the Met Office, and corresponding sea ice analysis (from EUMETSAT Ocea and Sea Ice SAF)
• Conserving interpolation scheme for trajectory fields in 4D-Var
• New variational bias correction (VARBC) bias predictors to allow the correction of infrared shortwave channels affected by solar effects
• Cleaner cold-start of AMSUA channel 14 bias corrections
• Changes to physics for melting of falling snow, albedo of permanent snow cover (e.g. over Antartica), diurnal variation of sea surface temperature, and linear parametrization schemes
• Convective contribution added to wind gusts in post-processing
• Monitoring of MERIS total-column water vapour data

The ECMWF model was upgraded to cycle 33r1 on 3rd June 2008 12Z. The main changes included in this cycle are:

• Improved moist physics in tangent linear/ adjoint model used in 4D- Var assimilation.
• Re-tuned entrainment in convection scheme.
• Bug fix to scaling of freezing term in convection scheme.
• Additional shear term in diffusion coefficient of vertical diffusion.
• Increased turbulent orographic form drag.
• Fix for soil temperature analysis in areas with 100% snow cover.
• Change in surface roughness for momentum, and change in post-processing of two-metre temperature and specific humidity.
• Assimilation of AMSR-E and TMI radiances in 1D+4D-Var; assimilation OMI ozone data.
• Usage of all four wind solutions for QuikSCAT in assimilation, rather than only two previously.
• Extended coverage and increased resolution for the limited area wave model.
• Improved shallow water physics and modified advection scheme for ocean wave models.
• Introduction of two new wave model parameters: maximum wave height and corresponding wave period.

The ECMWF model was upgraded to cycle 32r3 on 11th March 2008 12Z. The main changes included in this cycle are:

• Integration of the Monthly Forecasting System with the medium-range Ensemble Prediction System (EPS).
• Use of persisted SST anomalies in all atmospheric forecasts
• Daily ocean-coupling of days 10 to 15 of 0000 UTC EPS forecasts
• Monthly Forecast run once per week from 0000 UTC on a Thursday as an extension of the 15 day EPS forecast from this base time
• Modified EFI products using the new unified re-forecasts
• New GRIB description for all Monthly Forecast products, analogous to the current medium-range EPS data

The ECMWF model was upgraded to cycle 32r3 on 6th November 2007 12Z.

The main changes included in this cycle are:

• New formulation of convective entrainment and relaxation timescale
• Reduction in free atmosphere vertical diffusion
• New soil hydrology scheme
• New radiosonde temperature and humidity bias correction
• Increase in number of radio occultation data from COSMIC
• Assimilation of AMSR-E, TMI, SSMIS window channels (clear sky)
• Assimilation of SBUV (NOAA-17, NOAA-18) and monitoring of OMI ozone data

The main changes to the EPS included in this cycle are:

• initial perturbation amplitude reduced by 30%
• singular vectors targeted on tropical cyclones are computed with the new moist physics package in the tangent-linear and adjoint models (as used in the operational in 4D-Var since cycle 32r2).

The ECMWF model was upgraded to cycle 32r2 on 5th June 2007 12Z

The main changes included in this cycle are:

• Three-minimization version of 4D- Var assimilation scheme (T95/T159/T255) with improved moist linear physics (cloud and convection).
• Improved parametrization of the heterogeneous ozone chemistry.
• New short-wave radiation scheme (RRTM-SW), plus McICA cloud-radiation interaction and MODIS albedo.
• Retuned ice particle size.
• Revised subgrid-orography scheme.
• Explicit numerical treatment of convection in the moist tangent linear model used in the calculation of tropical singular vectors.

ECMWF upgraded its Ensemble Prediction System (EPS) and introduced the Variable Resolution Ensemble Prediction System (VarEPS). In particular, the forecast range was extended to 15 days using the VarEPS system with a resolution of T399 L62 for day 1 to day 10 (leg 1) and T255 L62 for T+246 to day 15 (leg 2).

The resolution of one-week ensemble prediction model of JMA was upgraded on 21 November 2007.

Major changes are:

• Increase in the resolution from TL159L40 to TL319L60 with a topmost level raised from 0.4hPa to 0.1hPa.
• Use of a new high-resolution analysis of sea surface temperature and sea ice concentration as ocean surface boundary conditions.
• Use of surface snow depth data from the domestic dense observational network in the global snow depth analysis.
• Introduction of a convective triggering scheme into the deep convection parameterization.
• Introduction of a new 2-dimensional aerosol climatology derived from satellite observations for the radiation calculation.
• Increase in the resolution of inner loop model of the four-dimensional variational (4D-Var) data assimilation system from T106L40 to T159L60.
• Introduction of a sigular vector method to make the initial perturbations.

Notes:

• The resolution and parameters of TIGGE data from JMA remains unchanged.
• Orography and Land Sea Mask in TIGGE data are slightly different from the previous data associated with the model change.

UM upgraded to version 7.4:

• Horizontal resolution upgraded to N216 (60km) from N144 (90km).
• Vertical resolution upgraded to 70 levels from 38 levels.
• SKEB2 upgraded with N216 tuning and velocity potential wind increments
• Bug fixed in wind gust diagnostic.
• CAPE and CIN formulations changed to bring into line with those of other Centres.
• Perturbations now formulated using vertical localisation to improve spread near the surface.
• Implementation was for the 12UTC cycle on 9 March 2010.

Implementation of E-suite 4. The model was upgraded to UM7.3 (released 26/3/09). The upgrade from UM6.3 represents 2 major and 5 minor releases of the model and brings the UK 15-day ensemble into line with its parent system and deterministic forecast system. There are many changes to the science schemes. RMS errors are improved in all areas with particular benefit noted in the northern hemisphere in the forecast range 6-12 days. The stochastic physics schemes SCV and SKEB1 were also replaced by the new SKEB2 scheme. This results in increased ensemble spread at all lead times (e.g. up to 10% in PMSL spread at T+10 days).

Implementation of E-suite 3. The model was upgraded to UM6.3 (released as a portable version 23/7/08). The upgrade from UM6.1 was primarily the implementation of the new configuration management system, although code restructuring in several schemes such as radiation and convection resulted in small improvements to RMS errors particularly in the tropics.

The UKMO TIGGE suite (MOTHS) was upgraded on 27 November 2007 00Z. The model version and stochastic physics schemes were not upgraded. UM Science Pack was upgraded from cycle 39 to cycle 44 (representing the operational deterministic model active as of May 2007 and the current parent 3-day ensemble forecast system).

The main features are:

• Change to the convective cloud which allows the cloud to decay away more slowly and more likely to influence the radiation scheme.
• Advanced adaptive detrainment for mid-level convection.
• Bug fix to freezing level calculation in convection.
• Bug fix to MSLP calculation over orography.
• Addition of biogenic aerosol climatology.
• Two corrections in the representation of convective clouds in the radiation scheme.
• Using MODIS observations of the surface albedo.
• Change to soil runoff formulation.
• Seasonally varying Leaf Area Index.
• SPARC ozone climatology instead of Li and Shine.
• A change from fixed SSTs to SSTs which evolve based on the climatology but with the SST anomaly at the start of the run persisted.

The UKMO TIGGE suite (MOTHS) was upgraded on 13 June 2007 00Z.

Model Version

• The UM was upgraded from Portable UM (PUM) version 6.0 to 6.1.

Stochastic Physics

• Random Parameters Scheme (RP) upgraded to version 2.
• Stochastic Convective Vorticity (SCV) upgraded from version 6.0 to 6.1.
• Additionally a (portability) bug was fixed in SCV that resulted in anomalous results in the tropics.
• Stochastic Kinetic Energy Backscatter (SKEB) was introduced at version 11.3.

UM Science Pack was upgraded from cycle 34 to cycle 39 (representing the operational deterministic model active as of June 2006). The main features are:

• Small improvements to mid-level convection.
• Introduction of the adaptive detrainment scheme.
• Changes to the formulation of the thermal roughness length.
• Other miscellaneous boundary level improvements.
• Updated soil parameter ancillary fields.

NAEFS upgrade, effective 12Z:

• GFS bias correction
• Combination of GFS & GEFS forecasts
• Probabilistic NAEFS forecasts
• Downscaled NAEFS forecasts

NAEFS Upgrade, effective 12Z:

• Ensemble size increased from 14 to 20 members

Ensemble Upgrade and NAEFS first Implementation, effective 12Z:

GEFS upgrade:

• increasing ensemble size from 10 to 14 members
• adding ensemble control for 0600 GMT, 1200 GMT and 1800 GMT
• introducing ET to breeding method
• NAEFS implementation:
• bias corrected forecast
• ensemble weights
• forecast anomalies

Ensemble Upgrade, effective 12Z:

• Increased resolution to T126 for all members between 180 hrs and 384 hrs (16 days)
• Changed initial pertubations from 24 hr breeding cycle to 6 hr cycle
• Added perturbed tropical storm vortex relocation

Effective 12Z: Bias-corrected QPF and PQPF forecasts

Effective 12Z: Ensembles available four times daily with T126 resolution out to 180 hrs

Effective 12Z: Mask Rescaling

Effective 12Z: Increased (T126) resolution for all members until 84 hrs

Effective 12Z: Change in regional rescaling procedure

Effective 12Z: Increased resolution for all members until 60 hrs

Effective 12Z: Increased membership at 12Z (10 members)

Effective 12Z: Increase in initial perturbation amplitude size

Effective 12Z: Change in regional rescaling procedure for setting initial perturbation amplitudes

Effective 12Z: New seasonally varying analysis uncertainty estimates introduced into regional rescaling procedure