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Home >  Products > Operational Upgrades > 2005 Higher resolution upgrade >     
   

Higher resolution model upgrade


 
 

 

ECMWF will upgrade both the horizontal and vertical resolution of its deterministic, Ensemble Prediction (EPS) and monthly forecasting systems. There will be no change to the forecast ranges with this implementation.

These upgrades do not apply to the ECMWF seasonal forecasting system.


 

This document will be updated as required and was last changed on 03.02.2006.

For a record of changes made to this page please refer to Document versions.

Further information and advice regarding the upgrade can be obtained from
User Support .


News

3 February 2006

The high resolution forecasting system T799 (deterministic) and T399 (EPS) was successfully implemented on Wednesday, 1 February 2006.

On 2 February 2006, the number of vertical levels in the monthly forecasting system was increased to 62.

 

18 January 2006

A revised dissemination schedule will be introduced in operations with the implementation of IFS Cycle 30r1 - "High Resolution" on 1 February 2006.

The new schedule is based on a much tighter internal production process that aims at accommodating the longer runtimes of the higher resolution system while at the same time delivering products as timely as possible. For a large range of products, in particular the EPS, the delivery times will be significantly earlier. A summary of the new times is given in Changes to the dissemination schedule below.

With the longer runtimes of the high resolution system and the much tighter production process, the de facto differences between dissemination, MARS and web based products access will become very small. Products will become available through MARS at the same time as they are available in dissemination.

All queries concerning the implementation of the new dissemination times or requests for additional information should be sent to User Support .

 

6 January 2006

A new version of the ECMWF model that includes a major resolution upgrade has been tested extensively in all seasons during 2004 and 2005. The final configuration has been run in experimental suite mode (e-suite) since the beginning of October 2005. This version of the forecasting system is now ready for implementation. The planned implementation date is Wednesday 1 February 2006. The BC suite from 06UTC and the main suite from 12UTC will be run on 1 February in the new configuration.

IFS cycle 30r1 includes the following changes:

  • Increase in horizontal resolution to T799 for the deterministic forecast and the outer loops of 4D-Var.
  • Increase in vertical resolution to 91 levels for the deterministic model. Model top raised to 0.01 hPa.
  • Increase in horizontal resolution to T255 for the second inner loop of 4D-Var.
  • Increase in horizontal resolution to T399 and in vertical resolution to 62 levels (model top approx. 5 hPa) for the EPS.
  • Increase in horizontal resolution to 0.36 degrees for the global ocean wave model.
  • Increase wave spectral resolution to 24 directions and 30 frequencies (from 12 and 25 respectively) for the EPS ocean wave model.
  • Use of grid-point humidity and ozone in 4D-Var.
  • Revised coefficients (version 2.3) for the linearised ozone chemistry scheme, supplied by Daniel Cariolle, CERFACS.
  • Use of Jason altimeter wave height data and ENVISAT ASAR spectra in the wave model data assimilation. ERS-2 SAR spectra are no longer assimilated.

The impact of the new cycle on the performance of the deterministic forecast system has been tested on more than 360 cases between July 2004 and December 2005. The e-suite is now running in near-real-time in step with operations.

The impact on the performance of the forecasting system has been evaluated comprehensively checking out all components of the system. There are small but statistically significant improvements to deterministic 500 hPa height forecasts over Europe and for both extra-tropical hemispheres out to day 6. Overall impact on weather parameters is modest, but precipitation scores over Europe are consistently improved, in particular for large daily rainfall amounts.

Tropical temperature and wind forecasts are generally better when verified against radiosondes. Tropical cyclone position and intensity forecasts are improved in the high resolution system with some spectacular results for the intense hurricanes, such as Katrina, which hit the US Gulf Coast last autumn.

There are increases in the number of observations used in the assimilation with better analysis and background departure statistics. Extra data also had a significant beneficial impact on the ocean wave analyses. Verification against independent observations confirmed improvements in the ocean wave forecasts.

The Ensemble Prediction System has been tested for some 30 cases in July and August 2005 and again in the e-suite over the period 17 October to 30 November 2005. The overall benefit of the higher resolution for the EPS is reflected in the results for the probability scores which are consistently improved for 500hPa height anomalies. In a similar way, the evaluation of precipitation events over Europe gave better results for the e-suite with respect to the Brier and ROC area scores.

Technical implications of the changes in IFS cycle 30r1:

  • The new model cycle will be used throughout the ECMWF forecast suites, including the monthly system and the BC Optional Project, but not in the seasonal (system 2) suite. The atmospheric model identification number in the GRIB headers will change from 126 to 127.
  • Model numbers for the Global wave model will remain at 116. Also for the European waters wave model the number will remain 216.

Other technical implications have been summarised here.

Further information about the higher resolution model upgrade including some case studies and scores for the IFS cycle 29r3 e-suite was given at the ECMWF Tenth Workshop on Meteorological Operational Systems, ECMWF, 14-18 November 2005. See the presentation The new ECMWF high resolution forecasting systemfor details.

Member State jobs submitted through the msjobs mechanism need to be tested and adapted by Member States themselves. Users will be reminded by User Support during January.

 

28 November 2005

The e-suite for the IFS cycle 30r1 deterministic T799L91 forecasts has been run since 18 November 2005.

The starting date of the e-suite was 30 September 2005, 12 UTC. All results are stored in MARS and are available to all users in Member States and Co-operating States for testing and adapting their applications to the high resolution forecasting system. The MARS Expver version number of the e-suite is 29.

We expect to run the high resolution EPS suite in the next couple of weeks. Information about test data from the high resolution EPS suite will follow as soon as such data are available.

For technical purposes, test data sets from the previous e-suite (IFS cycle 29r3) can still be used.

Implementation of the high resolution forecasting system is planned for early 2006, aiming at the second half of January.

 

4 November 2005

The problems encountered with IFS cycle 29r3, which have been described in previous updates, have now been addressed and corrective action has been taken. The IFS cycle 29r3 e-suite was terminated after reaching 31 October.

A new IFS cycle 30r1 of the forecasting system has been created with the following modifications:

  • revised Rayleigh friction to avoid a spurious mesospheric jet;
  • smoothed trajectory in the tangent linear computations to avoid occasional computational instability;
  • revised convergence criteria to avoid premature exit of the analysis from the minimization;
  • modified analysis increments at the top of the model to avoid unrealistic changes to temperature, humidity and ozone.

E-suite testing is expected to commence next week or soon afterwards. Further information will be provided when new experimental data become available.

For technical purposes, test data sets from the previous e-suite (IFS cycle 29r3) can still be used.

Implementation of the high resolution forecasting system is now planned for early 2006, aiming at late January.

 

22 September 2005

The test suite continues and will soon start to shadow operations in near real-time. Next we will run extensive EPS tests to evaluate the synoptic performance of the deterministic and probabilistic systems during episodes of severe weather this summer and autumn.

We are still addressing the occurrences of instability of the tangent linear model mentioned on 5 September. We expect to have a solution for the problem within a few weeks. Depending on the nature of the modifications we will then decide on the length of additional e-suite testing to be carried out in parallel in Research and Operations.

In any case, this will result in a delay of the implementation of IFS cycle 29r3 into operations. Implementation is now planned for the first half of December or early in 2006.

 

5 September 2005

In extensive final testing of the T799L91 system in e-suite and research runs, we have experienced a few occurrences of instability of the tangent linear model used by the data assimilation system. These instabilities result in convergence problems in the second, high-resolution minimisation.

This problem in the high-resolution forecasting system is currently being addressed. At this stage, we expect a delay of several weeks with the implementation of the new system.

The e-suite for the deterministic T799L91 forecasts has been run since 1 July 2005. All results are stored in MARS and can be used for technical test purposes by Member States users. The version number of the e-suite is 28 (MARS parameter expver=28 - see Test data sets from pre-operational e-suite).

 

18 August 2005

The e-suite for IFS cycle 29r3 (high resolution forecasting system) was suspended on 3rd August. Problems had occurred with large increments developing in the data assimilation cycles near the top of the model with a build-up of excessive moisture at those levels creating convergence problems in the 4D-Var minimisation.

Corrective action was taken by adding a dampening of the increments on the last few levels towards the top of the model. The modification was tested successfully and the e-suite was restarted on 17th August with a starting date of 1st July 2005.

The target date for the implementation of the high resolution forecasting system is still end of September/early October depending on the progress with the running of the e-suite.

 

Timetable

The planned timetable for the higher resolution model implementation (IFS cycle 30r1) is as follows:

  • End June 2005: First operational testing
  • Mid-July 2005: First high resolution test data sets for selected operational suites available in MARS
  • July 2005: Start of operational “e-suite”
    • Meteorological test data sets for all operational suites available in MARS
  • January 2006: Parallel test dissemination for selected dates.
  • 1 February 2006: Implementation.

The timetable given here represents our current expectations and may have to be reviewed in light of the actual progress made.

This cycle of the IFS model is primarily to implement the higher resolution upgrade. No other significant meteorological changes are planned for this model change.

Further information regarding previous changes to the IFS model can be found at:

http://www.ecmwf.int/products/data/technical/model_id/.

 

Resolution changes

Atmospheric model

  Deterministic Ensemble Prediction
System (EPS)
Monthly Forecast
(MOFC)
 
Current
Upgrade
Current
Upgrade
Current
Upgrade
Spectral
T511
T799
T255
T399
T159
T159
Gaussian
N256
N400
N128
N200
N80
N80
Dissemination (LL)
0.5
0.25
1.0
0.5
1.5
1.5

Model Level
Vertical resolution

60
91
40
62
40
62
 

No increase in the number and definition of the pressure levels is planned.

 

Wave model

  Deterministic Ensemble Prediction System (EPS) European Shelf (Mediterranean) Monthly Forecast (MOFC)
 
Current
Upgrade
Current
Upgrade
Current Upgrade
Current
Upgrade
Lat/Long
0.5
0.36
1.0
1.0
0.25
0.25
1.5
1.5
Dissemination (LL)
0.5
0.25
1.0
1.0
0.25
0.25
1.5
1.5
Frequencies
30
30
25
30
30
30
25
25
Directions
24
24
12
24
24
24
12
12

Ocean model

There will be no changes made to the resolution of the ocean model used in the monthly forecasting system.

 

Model levels

New model level definitions are available for L91 and L62.

A list of all other model level definitions currently in use is available at:

http://www.ecmwf.int/products/data/technical/model_levels/.

 

New vertical resolution for the deterministic model: L91

The correspondence between the current L60 (blue) and the new L91 (red) model levels is shown in the figure.

Correspondence between L91 and L60

 

In L91 the vertical resolution is increased everywhere compared to the 60-level resolution, with the largest increase around the tropical tropopause (100hPa), where the resolution is doubled.

Click on the figure to see a full-size copy. A printable version is also available.

A t able showing the correspondence between the L60 and L91 model levels is available.

 

New vertical resolution for the EPS: L62

The new vertical resolution for the EPS will have 62 levels, with the top full model level located at ~5hPa. The current EPS vertical resolution has 40 levels with top at 10hPa. The location of the levels in L62 is identical to the location of the levels in the vertical resolution of the deterministic model (L91) from the surface to about 150hPa. Above this pressure the EPS vertical resolution (L62) gradually becomes coarser than the 91-level resolution. This correspondence between the new EPS resolution (L62) and the new deterministic resolution (L91) is very similar to the correspondence between the current EPS resolution (L40) and the current resolution of the deterministic model (L60).

A table showing the correspondence between the L40 and L62 model levels is available.

 

Gaussian definitions

Descriptions of the Gaussian Grids for N400 and N200 used with the higher resolution model are available.

For a catalogue containing the descriptions of all other Gaussian Grids as well as the correspondence between the three types of grid resolutions (Spherical Harmonic, Gaussian Grid and Latitude-Longitude) please refer to:

http://www.ecmwf.int/products/data/technical/gaussian/.

 

Impact on users

Field sizes

If no specific spectral resolution or grid is given then the increase in horizontal resolution will result in a corresponding increase in the sizes of fields obtained via dissemination or retrieved from the MARS archive:

  • For model output in Spherical Harmonics or on Gaussian Grids data sizes will increase by a factor of 2.5
  • For model output on Latitude-Longitude grids data sizes will increase by a factor of 4

The increase in the number of vertical model levels will increase the size of data by a further factor of 1.5.

 

Dissemination

There are a number of issues that need to be addressed before the implementation of the resolution upgrade:

  • Any dissemination requests that use the GG/AUTOMATIC directive will need to be checked. This will be undertaken by ECMWF.
  • The choosing of nearest “new” model level will require manual intervention. This will be undertaken by ECMWF. Tables showing the correspondence between old and new model level definitions for L60 and L91 and L40 and L62 are available (see also Model levels).
  • Nearest GRID point coordinates for Weather parameter requests will change. Member and Co-operating States will need to choose new GRID points coordinates or rely on interpolation.
  • Line capacity should be checked to ensure that there is sufficient bandwidth available to support the possible increase in field sizes.

All results from the e-suite runs are available from the MARS archive. A test data set based on current operational dissemination requirements will become available through dissemination around the middle of January. We are now in the process of migrating all Member States’ dissemination requirements to the high resolution system. Test dissemination of e-suite data (deterministic model, EPS, wave and wave EPS) will be made available as version number 29.

On the day of implementation, we intend to provide you with dissemination products which are compatible with the current products, i.e. they will be provided at the same horizontal resolution as currently disseminated. Users will be able to request data at higher resolution after implementation of IFS cycle 30r1. Users of model level data are kindly asked to take note of and accommodate the changes in model levels, i.e. different model level numbers and positions. For existing requests, we have selected the nearest model levels which match the existing (L60) vertical structure as closely as possible.

Together with the implementation of the resolution upgrade the products dissemination schedule will be revised and products will be available earlier. Further information on the new schedule will be provided later in January.

 

Member State jobs

Member State users will be responsible for testing and checking the output of their jobs that use the new higher resolution data sets. In particular:

  • Check new disk space requirements.
  • Check new memory and CPU requirements and update Loadleveler directives of their jobs if necessary.
  • Check line bandwidth requirements for transferring the data.
  • Check the correspondence between “new” and “old” model levels if appropriate.

These tests can be carried out as soon as the e-suite test data becomes available.

 

Member State projects

Those responsible for Member State projects (e.g., COSMO-LEPS, NORLAMEPS) as well as the common applications (HIRLAM, FLEXTRA, meso-nh, Lokal Modell, etc) running at ECMWF will need to:

  • use test data sets to run “e-suites” and decide on new configuration;
  • review resource requirements (disk space, memory, CPU and line bandwidth).

 

Boundary Condition project

The same resolution changes as for the main deterministic forecast will also be applied to the BC project forecast runs. The impact on field sizes and dissemination will be as described above.

Test data sets for the Boundary Condition project at the higher resolution (T799L91) have been stored in MARS and can be used for technical testing purposes (see Test data sets from pre-operational e-suite (IFS cycle 30r1) ).

 

EPSgrams

The EPSgram facility has been upgraded in preparation for the implementation of the higher resolution model upgrade. The interfaces are fully compatible and the upgrade should be transparent to the user.

 

Other issues

The impact of the higher resolution model upgrade on

  • Member State SMS jobs
  • Trajectory models (FLEXTRA, etc)

is still being investigated. Further information regarding these points will be made available in this document as soon as it becomes available.

Users with other issues that are not covered here are urged to contact User Support as soon as possible.

 

Software

EMOS Library

A new version of the EMOS library (release 000281) has been available since 27 June 2005 on the Linux PC/Cluster, IBM servers, and IBM HPCC/HPCD and includes support for the horizontal and vertical resolution model upgrade. This has been the default version since 7 September 2005.

Both double and single precision versions of the library are available on each platform.

Please check that your codes work correctly with the 000281 version of the library and report any problems to User Support or Call Desk.

The 000281 version of the library includes several changes needed for the resolution upgrade, notably

  • New Gaussian definitions
  • New automatic truncation

The truncation can be controlled using the truncation option in INTIN. For further information about the interpolation routines available in EMOSLIB see:

http://www.ecmwf.int/publications/manuals/libraries/interpolation/.

Note that high resolutions need more resources to carry out the required processing.

For more information about changes to the EMOS library, please refer to:

http://www.ecmwf.int/publications/manuals/libraries/emoslib/.

For Member State users an export (web downloadable) version of the new EMOS library version 000281 is available at:

http://www.ecmwf.int/products/data/software/download/interpolation.html.

 

MARS

MARS users retrieving fields on model levels will need to change their retrieval directives to take into account the change in vertical resolution. In particular, retrieval commands that use the LEVELIST = 1/to/60 directive need to be checked and changed if necessary.

Users should also be aware of the effect of the RESOL directive when retrieving spectral fields in spherical harmonics form. If the RESOL directive is not specified then fields will be retrieved at the new higher resolution. If RESOL is specified then triangular truncation of retrieved data will take place accordingly before any selected post-processing and the behaviour will be as expected.

Spectral fields are automatically truncated before interpolation to grid fields to reduce data volumes and spurious ‘aliased’ values. For a table detailing the default truncations please refer to the MARS User Guide.

Note that high resolutions need more resources (memory, CPU and disk space) to carry out the required processing.

 

Magics

Magics applications will need to be relinked with EMOS library cycle 000281 to cope with the new Gaussian definition.

A new export version (Magics 6.10) was made available on 5 October 2005 to Member State users and can be ordered from:

http://www.ecmwf.int/products/data/software/magics.html.

Known bug: Plotting fields in T799 spectral format.

Spectral fields cannot be plotted without converting them first into grid point representation. If you try to plot T799 data without first converting it, then Magics tries to do the required conversion. Unfortunately one array inside Magics is too small.

A correction is available here:

http://www.ecmwf.int/publications/manuals/magics/current/Known_Bugs_and_Problems.html

At ECMWF the Magics Test version (use newmagics) contains the above correction.

 

Metview

Metview version 3.8-export was made available on 30 August 2005. This latest export version includes support for the horizontal and vertical resolution upgrade and can be ordered from:

http://www.ecmwf.int/products/data/software/metview.html.

Known bug: Plotting fields in T799 spectral format

Spectral fields cannot be plotted without converting them first into grid point representation. If you try to plot T799 data without first converting it, then Magics tries to do the required conversion. Unfortunately one array inside Magics is too small.

A correction is available here:

http://www.ecmwf.int/publications/manuals/metview/install/3.8/KnownBugs.html#fix051123

Note: Older Metview releases, up to Metview 3.7.1-export, are not able to handle the highest resolutions.

At ECMWF the Metview Test version (metview_new) contains the above correction.

 

Test data sets from pre-operational e-suite (IFS cycle 30r1)

The IFS cycle 30r1 e-suite for the deterministic T799L91 forecasts has been run since 30 September 2005. All results are stored in MARS and can be used for technical test purposes by Member States users. The version number of the e-suite is 29 (MARS parameter expver=29).

The IFS cycle 30r1 e-suite for the EPS T399L62 forecasts has been run since 16 October 2005 and results are also stored in MARS. Since 1 November 2005, only the 00UTC EPS forecast has been run. The version number of the e-suite is 29 (MARS parameter expver=29). EPS T399L62 data on model levels will be made available during January 2006.

These data sets are only available to registered users of ECMWF computing systems.

The quality of these data sets is not guaranteed. Please report any problems you find with this data to User Support . The data is intended for testing technical aspects of the resolution upgrade.

 

Changes to the dissemination schedule

A revised dissemination schedule which will be introduced in operations with the implementation of IFS Cycle 30r1 - "High Resolution" on 1 February 2006.

The new schedule is based on a much tighter internal production process that aims at accommodating the longer runtimes of the higher resolution system while at the same time delivering products as timely as possible. For a large range of products, in particular the EPS, the delivery times will be significantly earlier.

Dissemination schedule for Analysis Products (all times in UTC)

  Time available (Jan 2006) Time available (from 1 Feb 2006)
AN 00:00
06:45
05:50
AN 12:00
18:45
17:50

Dissemination schedule for Deterministic Forecast Products (all times in UTC)

  Time available (Jan 2006) Time available (from 1 Feb 2006)
FC Day 1
07:15
06:03
FC Day 5
07:55
06:35
FC Day 10
08:45
07:15

Times for the 12 UTC forecast run are equivalent by adding 12 hours

Dissemination schedule for EPS Products (all times in UTC)

  Time available (Jan 2006) Time available (from 1 Feb 2006)
FC Day 0
09:35
08:25
FC Day 10
10:15
09:05

Times for the 12 UTC forecast run are equivalent by adding 12 hours

Dissemination schedule for Monthly Forecast Products

All products from the monthly forecasting system will become available for dissemination at 22:00 UTC every Thursday of the week.

 

Detailed information about the new schedule for all dissemination streams of the various types of products can be found in the Dissemination Manual on our web site:

 

Document versions

Date
Reason for update
15.07.2005 Initial Version.
18.07.2005 Improved description of Model levels.
25.07.2005 Added comment on impact for BC Project.
18.08.2005 E-suite was restarted (see News).
05.09.2005 Announced delay with the implementation of High Resolution Forecasting System (see News).
Added tables giving correspondence between old and new Model levels.
Announced release of Metview version 3.8-export for Member States.
Announced availability of Test data sets from pre-operational e-suite in MARS.
22.09.2005

Further announcement regarding the implementation of High Resolution Forecasting System (see News).
EMOSLIB 000281 now the default version.

04.11.2005

Further announcement regarding the implementation of High Resolution Forecasting System (see News).
Announced release of Magics version 6.10-export for Member States.

28.11.2005

Announced start of the e-suite for IFS cycle 30r1 (see News).
Made available fix for known bug in plotting fields in T799 spectral format (see Magics, Metview).

06.01.2006

Announced implementation date (see News).
Removed reference to previous e-suite data.

10.01.2006 Clarified that there will be no change to the forecast ranges.
18.01.2006 Announced Changes to the dissemination schedule for IFS cycle 30r1 and introduction of harmonised access times to the products (see News).
Announced availability of e-suite data for the Monthly Forecasting System .
03.02.2006 Announced successful implementation of the high resolution forecasting system (see News).

 


 

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