Production suite overview

Recent Changes to Operational Runs

Tuesday December 13th 2005

Major changes to the Ensemble Prediction System (EPS)

Some new types of observations will start being used by the Ensemble Kalman filter (EnKF) data-assimilation system which itself will also benefit from some structural improvements.

The ensemble of forecast models has been revised to arrive at a better simulation of the diurnal cycle and to have a reduction in model biases. The forecasts will be performed twice daily and the forecast period will be extended from 10 days to 16 days.

Further details about this implementation are available in the official announcement note.

Wednesday December 7th 2005

Assimilation of new satellite data

On Wednesday December 7th 2005, the Canadian Meteorological Centre will update its Assimilation System by including the data from the NOAA-18 and METEODAT-8 satellites recently put into orbit. For the moment only the global and regional GEM models will benefit from this update. The impact on forecasts has been evaluated as being neutral, as expected for such updates.

Further details about this implementation are available in the official announcement note.

Thursday July 21st 2005

Modifications to the Canadian Wave model

On Thursday July 21st 2005, the Canadian Meteorological Centre will implement modifications to the Wave Forecast System over the Northern domains of the Atlantic and Pacific Oceans. This implementation will also introduce 4 new windows of wave forecast to cover the following domains in the Great Lakes : Ontario, Erie, Huron and Superior.

Further details about this implementation are available in the official announcement note.

Wednesday July 6th 2005

Improvements to Chronos air quality forecast

On July 6^th 2005 the Canadian Meteorological Centre will implement new version of the Chronos air quality forecasting model. Anthrogenic emissions of 2000-2001 will replace the 1995 emissions. The processing of the emission inventory was done using SMOKE (Sparse Matrix Operator Kernel Emissions) instead of CEPS (Canadian Emissions Processing System). The biogenic emissions have also undergone significant modifications using BELD3 vegetation categories instead of USGS (U.S. Geological Survey) and upgrading the associated emissions rates to BEIS3 instead of BEIS2. In brief more vegetation types are now used with updated emissions rates.

Further details about this implementation are available in the official announcement note.

Wednesday July 6th 2005

Improvements to the quantity of precipitation forecast in summer situations for the Regional GEM model

On July 6^th 2005 the Canadian Meteorological Centre will implement a minor change to the regional forecasting system to improve the quantity of precipitation forecast in summer situations. In addition to this change, a new analysis of sea surface temperature will be introduced featuring higher resolution and fed with more data.

Further details about this implementation are available in the official announcement note.

Tuesday March 15th 2005

4D-Var: a major improvement to the Canadian global data assimilation system

On Tuesday, March 15th 2005, the 3D-Var (3-Dimensional Variational) data assimilation system for the global forecasting suite will be extended to a 4D-Var scheme. This extension to include time as the fourth dimension of the analysis system implies that the analysis is no longer a simple snapshot of the atmospheric conditions at the time of the analysis (like in the 3D-Var which does this for the primary synoptic hours). Instead, the 4D-Var system provides a time evolution of the atmospheric conditions during the assimilation time window (for the current implementation, this window was chosen to maintain coherence with the 3D-Var, that is 6 hours centered on the main synoptic hours). The 4D-Var analysis is done by using the GEM forecast model itself as part of the assimilation process, and by using observations that are well distributed during the analysis time window. The 4D-Var then computes the best fit between these observations and the model forecasts. The resulting analyses show a much improved dynamical consistency and are accompanied by a significant improvement in the global system performance.

Further details about this implementation are available in the official announcement note. A more detailed technical document is also available. Documents on objective and subjective verification are also available.

Thursday January 13th 2005

Improvement to the surface temperature forecasts from the GEM regional model

On Thursday January 13, 2005, at 12 UTC, the Canadian Meteorological Centre will implement a minor change to the regional model forecast system in order to improve nocturnal surface temperature forecasts.  It has been noted that the operational GEM regional model forecasts excessively cold nocturnal surface temperatures, especially during winter, under clear skies and in weak low-level circulation regimes.  This problem has been noted more systematically in mountainous regions as well as in the Arctic. The change aims to correct this problem.

Further details about this implementation are available in the official announcement note.

Wednesday January 12th 2005

Implementation of the Ensemble Kalman Filter data assimilation method in CMC's Ensemble Prediction System

As of Wednesday January 12 2005 at 00 UTC, the Canadian Meteorological Centre implemented a major change to the data assimilation of the Ensemble Prediction System. The Optimal Interpolation technique was replaced by an analysis cycle based on the Ensemble Kalman Filter. The model configuration of the 16 members used to produce the 10 day forecasts remains unchanged. The first forecasts using the new assimilation technique were produced in the 00Z run of 13 January 2005.

You will find details about this implementation inside the official announcement note. A more detailed technical document on the Kalman Filter is available by clicking here.

Tuesday September 21st 2004

New observations incorporated in the regional and global data assimilation systems at CMC

As of Tuesday September 21 2004 at 1200 UTC new observations will be incorporated in the regional and global 3D-VAR (3-Dimensional VARiational) data assimilation system. First, IR radiance data from the 6.7 micron channel from the GOES-12 (East) satellite will be incorporated, in addition to the GOES-10 (West) data which is already used. Also, data from the AMSUA instrument onboard the NASA AQUA satellite will also be assimilated. This will complement the AMSUA data already used for the NOAA-15 and NOAA-16 satellites and will partly compensate for the loss of the AMSUA instrument for NOAA-17 which occurred in late October 2003. There are also some changes to the ATOVS (AMSUA and AMSUB) thinning process and the variational quality control will also be applied to ATOVS data. A third change is the incorporation of satellite winds in the Polar Regions obtained from the MODIS instrument onboard the NASA AQUA and TERRA satellites. Modifications to the data selection aiming at increasing the number of satellite winds from the GOES-P satellite are also included. Finally, data from selected USA wind profilers will also be assimilated.

You will find details about this implementation inside the official announcement note. A more detailed technical document is also available.

Tuesday May 18 2004

Implementation of the 15km GEM regional model and of improvements to the regional data assimilation system

CMC will implement major changes to the operational regional forecast system on Tuesday May 18 2004, at 12 UTC. The horizontal resolution of the GEM model will increase from .22 degree (about 24 km) to 0.1375 degree (about 15 km) in the uniform resolution portion of the grid.  The number of vertical levels will increase from 28 to 58, the top of the model remaining at 10 HPa.  The model's physics package will be improved.  The Kain-Fritsch scheme will replace the Fritsch-Chappell scheme for deep convection while a new shallow convection scheme, based on a Kuo scheme closure, will complement the more selective deep convection scheme.   As well, the package features a new sub grid scale orographic parameterization (gravity wave drag and a blocking term).  

Changes will also be made to the regional data assimilation system.  It will use of satellite radiance data from the AMSU/B instrument, in addition to the data from the AMSU/A instrument that are currently assimilated. Irradiance data from the 6.7 micron channel from the GOES-W satellite (GOES-IR) will also be assimilated.  The addition of AMSU/B and GOES-IR data, which are sensitive to both atmospheric temperature and moisture, has the most impact over oceans where more channels are assimilated. These changes are the same that were successfully implemented in June 2003 in the global system. This upgrade to the regional system will bring the two systems to the same level.

You will find details about this implementation inside the official announcement note.  Also a more detailed  technical document is available.

Thrusday June 19 2003

Improvements to the global data assimilation system 

As of Thursday June 19, 2003 at 1200 UTC the 3D-VAR (3-Dimensional VARiational) data assimilation system will now make use of satellite radiance data from the AMSU/B satellite instrument in addition to the data from the AMSU/A instrument which are currently assimilated.  The AMSU instruments are part of the ATOVS sounder on-board the NOAA-15, NOAA-16 and NOAA-17 satellites. As well, the assimilation of IR radiance data from the 6.7 micron channel on the GOES-W will be introduced.  Since AMSU/B and GOES-IR data are sensitive to both temperature and moisture, the addition of the new data has a large impact on the moisture analyses that are used by the numerical models. It is expected that the use of these new data will result in significant improvements in moisture analyses and some modest improvement in the model performance. You will find details about this implementation inside the official announcement note.
Due to time constraints imposed by the conversion to the new IBM supercomputer, the regional data assimilation and forecast system will not make use of these new datasets. The regional system will continue to use the same dataset as it currently does. There will however be some impact on the regional system due to the use of the global analyses at the beginning of the regional spin-up cycle. Work is underway to incorporate the AMSU/B-GOES data in the regional system, but this modification will not be implemented until the new supercomputer is operational. 

Febuary, March and April 2002

Minor changes to the operational system in February, March and April 2002:

• 19 Febuary 2002: a correction was made in the regional and global assimilation system to the thinning of SATWINDS data in order to ensure a better treatment of the data near the edges of the selection boxes. As well, a correction to the Humsat system was implemented. This corrected a bug which in certain cases was causing a erroneous evalution of the value of the cloud fraction during daytime.

• 27 March 2002: the thinning process of aircraft data was improved in the data assimilation systems. Also, the rejection criterea applied to "dropsonde" data within the background check process was modified to reduce the number of wind data rejections over the Pacific Ocean. As well, a correction was made to the interpolation process near the computing pole of the grid in order to eliminate problems when processing data at that point.

• 24 avril 2002: a modification was made to the calculation of the geopotential in pressure coordinates in the GEM regional model. Since 11 January 2001 the geopotential was computed using a cubic interpolation of the model fields in eta coordinates. Recently, it was clearly demonstrated that this method caused a degradation of the geopotential near and above 250 hPa level. Consequently, the previous more precise method was re-introduced which is a linear interpolation done after the recomputing of the geopotential. The meteorological impact of this problem is fairly limited. However, the problem had a negative effect on the monthly verification scores of the geopotential near and above 250 hPa level.

Tuesday, December 11, 2001, 12Z

Implementation of a major change to the analysis and of an improved global GEM model

CMC Operations will implement a major change to the global and regional assimilation systems Tuesday 11 December 2001 at 12UTC.   As well modifications will be implemented to the GEM global model in order to improve the treatment of winds over the mountains.  The most important change to the assimilation scheme is that temperature and surface pressure will now be directly assimilated thus replacing geopotential height which will now be a diagnosed variable. Also, assimilated radiosonde levels will pass from 16 to 27 levels. Additional datasets will be assimilated. These are dropsondes, temperature data from AMDAR and ACARS, five additional TOVS channels below 500 hPa and satwinds from GOES 8 and 10. The new assimilation scheme will also include a full 3-D VAR quality control module in addition to a background check for the detection of gross errors, thus replacing the OI quality control package. All the above changes are common to both global and regional assimilation systems.

Changes in the GEM global model  include a numerical correction to the existing gravity-wave drag scheme and the addition of a low level blocking term to the sub-grid scale orographic scheme. Practically this will result in a better handling of the wind over high mountains like the Rockies and the Himalayas.  The regional model remains unchanged.

You will find the official  announcement on this change here.  A detailed document (PDF Version) describes all the changes and their significant positive impacts on the global and regional analysis and forecast systems.

Tuesday, September 11, 2001, 12Z

Implementation of the ISBA surface scheme in the GEM regional model

CMC Operations implemented a change to the regional forecast system Tuesday 11 September 2001 at 12UTC.  A new surface modeling scheme known as ISBA (Interactions, Surface, Biosphere, Atmosphere) replaced the so-called "force-restore" module.  The ISBA scheme improves the treatment of surface processes by taking into account the surface fluxes of heat, moisture, and momentum over the various surfaces (land, water, sea ice, and glaciers). The fluxes calculated over these four land types are combined over each grid tile according to their respective weights. These fluxes are then used as a lower boundary for the vertical diffusion.  The "force-restore" scheme considered only one land type for each model grid title.  You will find detailed information on this change and its impact in the official note. As well a technical note (PDF Version) describes how the ISBA scheme works.

Thursday, June 7 2001, 06Z

Implementation of ATOVS level 1B data in the of global and regional analysis system

CMC Operations implemented a change to the global and regional data assimilation and forecast systems Thursday June 7 2001 at 0600 UTC. The ATOVS-1B data have replaced the TOVS-1D data which were received via the GTS (Global Telecommunication System). The new ATOVS data are now collected directly from a NESDIS server via the internet. As well note that the ATOVS data are obtained from the NOAA-15 and NOAA-16 satellites. The new raw ATOVS-1B data are calibrated at CMC. The new dataset is significantly larger and amounts to approximately 670,000 observations per 24 hours. The impact of the introduction of the ATOVS-1B data was studied in the last few months. The results suggest a general improvement in forecast quality especially in the Southern Hemisphere.

Thursday, January 11 2001, 12Z

Improvements to the regional analysis: new "eta" coordinates and addition of TOVS and ACARS/AMDAR data

CMC Operations will implement changes to the regional data assimilation and forecast systems Thursday January 11 2000 at 1200 UTC. We will introduce in the regional analysis system the modifications which were made to the global system last June 2000 (analysis on eta model coordinates) and in last September 2000 (addition of TOVS and ACARS/AMDAR data). The 3D-VAR (3-Dimensional VARiational) data assimilation will then be performed on the model coordinates and, as well, will make use of automated aircraft observations, that is ACARS and AMDAR data, in addition to the AIREP data which are currently assimilated. We are also incorporating satellite radiances from NOAA-14 TOVS and NOAA-15 ATOVS instead of the NOAA-14 SATEM data (temperature profiles derived from radiances). You will find detailed information on this change in the official note.   As well, technical notes are available on the assimation of TOVS  and ACARS/AMDARS data.

Wednesday, September 27 2000, 12Z

Improvements to the global analysis: addition of TOVS and ACARS/AMDAR data

CMC Operations will implement changes to the global data assimilation and forecast systems Wednesday September 27 2000 at 1200 UTC.  The 3D-VAR (3-Dimensional VARiational) data assimilation will now make use of automated aircraft observations, that is ACARS and AMDAR data, in addition to the AIREP data which are currently assimilated. We are also incorporating satellite radiances from NOAA-14 TOVS and NOAA-15 ATOVS instead of the NOAA-14 SATEM data (temperature profiles derived from radiances).   You will find detailed information on this change in the official note. As well, technical notes are available on the assimation of TOVS  and ACARS/AMDARS data. Note that the regional assimilation and forecast system remains unchanged.

Wednesday,June 14 2000, 12Z

Implementation of a new global analysis on "eta" coordinates

CMC Operations will implement changes to the global data assimilation and forecast systems Wednesday 14 June 2000 at the 12Z run.  The new global analysis on "eta" coordinates will be implemented.  The 3D-Var data assimilation will be performed directly on the GEM model 28 eta vertical levels rather than on the current 16 standard pressure levels.  At the same time, a new version of the GEM model in the global configuration will also be implemented.  The main impact of this last change is to increase the level of activity in the model.  You will find more information in the  official note. The regional assimilation and forecast system remains unchanged.

Wednesday,October 14 1998, 12Z

Implementation of a new global forecast model

CMC Operations will implement the global uniform grid version of the GEM model Wednesday October 14^th at the 12Z run. The GEM model in global configuration will replace the T199 version of the global SEF spectral model which is currently used to produce the medium and long range forecasts at CMC. The new model, which has a latitude-longitude resolution of 0.9°, will be also used in the global data assimilation system to generate the trial fields for the global analyses. The official note (GENOT) describes the main differences between GEM global and the spectral SEF model and summarizes the results of the objective and subjective evaluations of the parallel run which has been in place during the past 5 months. The article from Côté et al. (1997) (PDF Version) gives additional details on the GEM model.

With this implementation, CMC now has a unified forecasting system in which a single model (GEM) is used in different configurations (global, regional, local). After running a barotropic model since the 1960s CMC implemented the first version of the spectral hemispheric T20L5 model in 1976. Fifteen years later, in 1991, the global version of the spectral SEF model (T79L21) was implemented. The model's horizontal resolution was increased to T119 in 1993, then to T199 (100km) in 1995. Note that the SEF model will continue to be used for the monthly and seasonal forecasts as well as in the ensemble forecasting system.

Tuesday, September 15 1998, 12Z

Implementation of the GEM, regional 24 km model.

CMC Operations will implement a new version of the GEM regional model on Tuesday, September 15 1998 at the 12Z run. The main changes affect the horizontal resolution of the model grid, which is increased from 35 km to 24 km, and the parametrization of the physical processes. For more information, please consult the official note (GENOT).

Wednesday, March 11, 1998, 12Z

Implementation of the new snow depth analysis.

CMC Operations will implement a new snow depth analysis on Wednesday, March 11, 1998, 12Z. This new analysis will have, among other things, an improved temporal and spatial resolution and will take into acount intermediate synoptic observations. In addition, we have significantly improved the analysis algorithm. For more information, please consult the official note (GENOT) or the detailed documentation (PDF Version) about impacts of this new analysis.

Thursday, January 22, 1998, 00Z

Improvement to the «force-restore» scheme of GEM.

CMC Operations implemented a modification to the GEM model on Thursday January 22nd 1998 at 00Z. This modification is an improvement to the «force-restore» scheme which allows to calculate the model surface temperature and humidity. These modifications will improve the surface temperature and dew point forecast during the winter season. An official note (GENOT) announcing this modification summarizes the results of the objective and subjective evaluations of the parallel run.

Wednesday, September 24, 1997, 12Z

Reintroduction of the regional data assimilation system at CMC

CMC Operations will reintroduce the regional data assimilation system (12 hour spin-up) on Wednesday September 24 1997 at 12Z.  This system had been turned off when the GEM model replaced the RFE model last February.  The 3D-VAR (3-dimensional variational) data assimilation system was adapted to the regional system which uses the GEM model to produce the 6 hour trial fields needed by the analysis.  The official note announcing this modification summarizes also the results of the parallel run.

Wednesday, June 18th 1997 at 12Z

3D-VAR, the new data assimilation system at CMC was implemented

CMC Operations has implemented a new data assimilation system on Wednesday June 18^th 1997 at 12Z. The 3D-VAR (3-dimensional variational) data assimilation system has replaced the operational OI (optimum interpolation) scheme that has been used at CMC since the last 20 years. The official note announcing this modification summarizes also the results of the parallel run. A detailed documentation on this new analysis is in preparation. In the meantime, you can consult the images from a Powerpoint presentation prepared by Pierre Koclas for the CMOS conference which was held in Saskaton in early June.

Tuesday June 10^th 1997 at 12Z

Modification to the analysis feeding GEM regional implemented

CMC Operations implemented a modification of the regional forecast system on Tuesday June 10^th 1997 at 12Z. The GEM regional model is now fed by the 21 level global analysis in sigma coordinates. Since the introduction of GEM, last February 24th, the model was being fed by the 16 level pressure global analysis. An official note annoucing this modification summarizes the results of the objective and subjective evaluations of the parallel run.

Monday 24 February 1997 at 12Z

The new GEM regional model was implemented

The new GEM regional model was implemented On Monday 24 February 1997 at 12Z CMC Operations implemented a new regional forecast model: the GEM (Global Environmental Multiscale) model. This new model replaces the operational RFE model that has been used to produce short range forecasts at CMC since April 22 1986. An official note announcing the implementation of GEM describes the differences between GEM and RFE and summarizes the results of the objective et subjective evaluations of the parallel run which has run during the last few months. The article by Côté et al. (1997) (PDF Version) describes the development and the characteristics of the GEM model and offers, as well, a more detailed discussion of the parallel run evaluation.

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