Page History

...

The page will be updated as required. It was last changed on 8 December 201510 February 2016.

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

...

...

• Compute scale-dependent hybrid B (background error covariance) by adding samples from latest EDA forecast to static climatological B with increasing weight of today's EDA for smaller wavelengths (30% up to T63, growing to a maximum 93% at T399).

• The EDA now cycles its own background error and covariance estimates, rather than using climatological estimates.

• Change to use the Sonntag equation for saturation vapour pressure in humidity observation operators to improve saturation calculation for very cold temperatures (colder than -40C).

• Assimilation of aircraft humidity data implemented.

Satellite:

• GPSRO (radio occultation) observation errors based on a physical error propagation model are increased by 25% to account for missing sources of error (e.g. observation error correlations, forecast model error). Improves lower stratosphere/tropopause winds and temperatures.

• Activated SSMIS F-18 humidity sounding channels over ocean and extended all-sky assimilation to snow covered land surfaces.

• Improved specification of AMSU-A observation errors based on satellite (due to instrument noise characteristics and ageing) and situation (cloud, orography) thereby increasing the number of observations assimilated.

• Improved aerosol detection and screening for IASI infrared satellite data.

• Increased use of Atmospheric Motion Vectors (AMVs), including extension in latitudinal coverage from geostationary platforms from 60 to 64 degrees zenith angle and addition of Meteosat mid-height AMVs derived from infrared imagery.

• Revised data selection (screening) of cold-air outbreaks in low-peaking all-sky microwave channels to allow more data to be assimilated.

• Updated microwave observation operator coefficient files (54-level RTTOV files with latest spectroscopy)

...

• Improved representation of radiation-surface interactions with approximate updates every timestep on the full resolution grid leads to a reduction in 2m temperature errors near coastlines.

• Included surface-tiling for long-wave radiation interactions to reduce occasional too cold 2m temperature errors over snow.
• Improved freezing rain physics and an additional diagnostic for freezing rain accumulation during the forecast.

• Introduced resolution dependence in the parametrization of non-orographic gravity wave drag, reducing with resolution and improving upper stratospheric wind and temperature for HRES and ENS.

• Changed the parcel perturbation for deep convection to be proportional to the surface fluxes, reducing overdeepening in tropical cyclones.

• Increased cloud erosion rate when convection is active, to reduce cloud cover slightly and improve radiation, particularly over the ocean.

• Improvements of linear physics used in the data assimilation for gravity wave drag, surface exchange and vertical diffusion, improving near-surface winds over ocean in the short-range.

• Correction to solar zenith angle for the sunshine duration diagnostic. For clear sky days the sunshine duration increases by 2 hours, now in good agreement with observations. For cloudy days, sunshine duration may now be overestimated due to an existing underestimation of cloud optical thickness.

• Improved solar zenith angle calculation removes stratospheric temperature dependence on radiation timestep and reduces anomalous small amplitude fluctuations in incoming solar radiation around the equator.

Ensemble:

• Modified SKEB (Stochastic Kinetic Energy Backscatter) stochastic physics necessary for the new cubic grid, removing the numerical dissipation estimate from the dissipation rate. Reduces ensemble spread slightly, but this is then consistent with reduced error (RMSE) in the new cycle.

• Modified singular vector calibration to compensate for increased variance from the higher resolution EDA.

...

Comparison of scores between IFS cycle 42r1 and IFS cycle 41r1 for HRES and ENS can be found in the IFS cycle 41r2 scorecard.

...

An additional diagnostic for freezing rain accumulation during the forecast is introduced. CAPE-Shear, previously introduced for the EFI, will be provided also for the HRES and ENS. A new wave product will also be introduced. The availability of test data for these new parameters will be announced via updates to this pageis indicated in the table below will be updated as the products become available.

paramId	shortName	name	units	GRIB edition	Component	Test data availabe	Dissemination	Proposed for Catalogue
228216	fzra	Accumulated freezing rain	m	1	HRES / ENS		Image Modified	TBC
228044	capes	Convective available potential energy shear	m2/s2	1	HRES / ENS		TBC	TBC
140120	sh10	Significant wave height of all waves with period larger than 10s	m	1	HRES-WAM / ENS-WAM / HRES-SAW		TBC	TBC

Correction to solar zenith angle for the sunshine duration diagnostic

...

A correction has been made to the interpolation method used by both MARS and product generation for the precipitation type diagnostic (shortName: ptype; paramId 260015) introduced at IFS cycle 41r1.  Users of this product on interpolated grids will obtain a field where the index-nature is preserved as integer values.  Previously, the interpolated product contained erroneous non-integer values.

The meaning of the integer values of the precipitation type diagnostic is as follows: 1=rain, 3=freezing rain, 5=snow, 6=wet snow, 7=sleet, 8=Ice pellets.

Discontinued ENS Calibration / Validation forecasts

...

The current ENS variable resolution overlap products from both atmosphere and wave forecasts and hindcasts (MARS class="OD", STREAM=EFOV, STREAM=EFHO, STREAM=ENWH, EWHO) provided from day 9 to 10 are discontinued. Overlap data is provided instead from day 14 to 15 for ENS Extended only, when it is run, twice per week on Mondays and Thursdays.

...

Simulated satellite images operationally available as charts from the ECMWF web site and as GRIB fields from MARS are currently not being produced by 41r2. Updates on their availability will be provided via this web page.

Anchor

...

ENSgrams ENSgrams

ENS meteograms

The ENS meteogram facility The ECMWF software stack has been upgraded to support the octahedral grid. This includes upgrades to EMOSLIB, MARS, Metview, GRIB_API and product generation (dissemination).

MARS - the meteorological archive

MARS has been adapted to support retrieval of data on the octahedral reduced Gaussian grid. Users can test the retrieval of IFS cycle 41r2 test data on ECMWF systems with the command:

mars <retrieve request>

...

The MARS post-processing keyword 'GRID' now accepts values comprising a letter denoting the grid name followed by an integer (the grid number) representing the number of lines from pole to equator.  For example, use:

• GRID = N640 to specify output on the original reduced Gaussian grid with 640 latitude lines between pole and equator;
• GRID = F640 to specify output on the full (or regular) Gaussian grid with 640 latitude lines between pole and equator;
• GRID = O640 to specify output on the octahedral reduced Gaussian grid with 640 latitude lines between pole and equator.

Not all grid names and grid number combinations are supported. MARS requests specifying an unsupported grid will fail.  For example, a retrieval request with GRID=O123 will return an error.  A list of supported grid names and grid numbers will be provided.

In addition, the MARS post-processing keywords GAUSSIAN=REDUCED and GAUSSIAN=REGULAR are deprecated.

...

.  The interfaces, both via the web and Metview 'meteogram' macro function, are compatible with the previous version.  However, the coordinates of the nearest grid points used for the ENS meteograms will have changed with the change of grid and resolution. Users should review and, if necessary, update the latitude-longitude points used for the station locations.

Users of the 10-day HRES ("classic") meteogram product available only via the Metview 'meteogram' macro function as type='10_days_metgram' should note that this plot type has been discontinued with the introduction of the octahedral grid.

Anchor
technical_software technical_software

Software

The ECMWF software stack has been upgraded to support the octahedral grid. This includes upgrades to GRIB_API , EMOSLIB, MARS, Metview, Magics and product generation (dissemination).  On 9 February the default versions on all ECMWF systems (ecgate, cca and ccb) have been updated as follows:

• GRIB API to version 1.14.5
• EMOSLIB to version 4.3.7
• Metview to version 4.6.4
• Magics to version 2.26.2

On the same day, the default version of MARS was updated to use these  libraries. For further details, see Change of default versions of ECMWF software packages on 9 February 2016.

MARS - the meteorological archive

MARS has been adapted to support retrieval of data on the octahedral reduced Gaussian grid. Users can test the retrieval of IFS cycle 41r2 test data on ECMWF systems with the command:

mars <retrieve request>

Anchor
mars_language mars_language

MARS language changes (MARS and dissemination)

The MARS post-processing keyword 'GRID' now accepts values comprising a letter denoting the grid name followed by an integer (the grid number) representing the number of latitude lines from pole to equator.  For example, use:

• GRID = N640 to specify output on the original reduced

...

• Gaussian grid with 640 latitude lines between pole and equator

...

• ;
• GRID = F640

...

• to specify output on the full (or regular) Gaussian

...

• grid with 640 latitude lines between pole and equator

...

MARS requests specifying GRID=AV will return the model grid.  After the implementation of IFS cycle 41r2, this will be O1280 for HRES, O640 for ENS (Day 0 - 15) and O320 for ENS Extended (Day 16 - 46).

The MARS keyword RESOL=N128 was used to truncate products from ENS Day 0 - 10 to the N=128 original reduced Gaussian grid of ENS Day 11 - 16 prior to interpolation to regular latitude-longitude grids. Following the horizontal resolution upgrade, anyone using this intermediate interpolation method should use RESOL=O320 to truncate O640 ENS Day 0 -15 products to the O320 octahedral grid of ENS Extended (Day 16 - 46).

• ;
• GRID = O640 to specify output on the octahedral reduced Gaussian grid with 640 latitude lines between pole and equator.

Not all grid names and grid number combinations are supported. MARS requests specifying an unsupported grid will fail.  Currently, the Gaussian grid names and numbers supported for MARS retrievals are:

For example, a retrieval request with GRID=N1280 or GRID=O124 will return an error. 

EMOSLIB

EMOSLIB versions from 000420 onwards provide support for interpolation of input octahedral grids to any of the previously supported grids as well as spherical transforms to the new octahedral grids.  For further information about how to use EMOSLIB to interpolate to the octahedral reduced Gaussian grid see Changes in version 000420.

GRIBEX: functionality superseded by GRIB_API.
ABORTX : Routine GRIBEX has requested program termination. 

EMOSLIB version 4.3.7 is the current default and includes additional performance improvements and bug fixes and users are strongly recommended to update to this version.

GRIB API

Full support for the octahedral grid is provided from GRIB API 1.14.5 and this  is default version used at ECMWF since 9 February 2016.  Users of the grib_find_nearest routine and the new simulated satellite products (not yet available) will need to upgrade to this version. 

Older versions of GRIB API can decode the octahedral grid successfully but users are advised to use at least GRIB API version 1.12.3.

All GRIB API versions are available for download from GRIB API releases.

Metview

Metview versions from 4.6.0 provide support for processing and visualising fields on the octahedral reduced Gaussian grid - see Metview Version 4.6 Updates.  Users wishing to install this version on their local systems are recommended to link with EMOSLIB 4.3.7 and GRIB API 1.14.5 or to use the The Metview Source Bundle 2016.01.0 or newer.

Magics

Magics versions from 2.26.0 provide support for visualisation of products on the octahedral reduced Gaussian grid. Users are recommended to upgrade to Magics 2.26.2 which is the default version in use on ECMWF systems since 9 February 2016 and can be downloaded from the Magics Releases page.

Anchor
technical_dissemination technical_dissemination

Dissemination

The MARS language changes described above apply also to the web based dissemination requirements tool.  In particular, the specification of Gaussian grid products has changed in the MARS language

•    GAUSSIAN=regular,GRID=640 changes to GRID=F640
•    GAUSSIAN=reduced,GRID=640 changes to GRID=N640

New octahedral grid based products can be requested by specifying GRID=O1280, etc.The following grid numbers are supported for all Gaussian grid names - full (F-grids), original reduced (N-grids) and octahedral reduced (O-grids) :

As before, any sub-area of the global field is supported

Two specific ENS Calibration / Validation forecasts (MARS class="OD", STREAM=ENFO, class="CV") will be discontinued with the implementation of IFS cycle 41r2. Any dissemination requirements requesting these products will be taken out of dissemination streams by ECMWF on the day of 41r2 cycle implementation.

ENS variable resolution overlap products (MARS class="OD", STREAM=EFOV, EFHO, ENWH and EWHO) provided currently from day 9 to 10 will also be discontinued. Thus, all EFOV, EFHO, ENWH and EWHO requirements will be taken out of dissemination streams by ECMWF on the day of 41r2 cycle implementation.

New overlap data, provided from day 14 to 15 for ENS Extended run, will have to be requested by users themselves once 41r2 cycle has been implemented.

Since there is no ENS resolution change for Days 0-15 in the IFS cycle 41r2, requesting of field resolution truncation in dissemination for Days 0-10 is no longer needed. The MARS keyword RESOL=N160 was used to truncate products from ENS Days 0-10 to the N=160 original reduced Gaussian grid of ENS Days 11-15 prior to interpolation to regular latitude-longitude grids. Users are strongly advised to remove any such  truncation request from their dissemination requirements.

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.

Anchor
technical_tc technical_tc

Time-critical applications

Option 1 - simple time-critical jobs

Member State users of the  "Simple time-critical jobs" framework can test that their scripts will work with the IFS cycle 41r2 test data by using the special 'events' set up for this purpose:

For these events, MSJ_EXPVER environment variable is set to 0069 and can be used to specify the IFS cycle 41r2 test data any MARS retrievals.

These events are  intended for testing technical aspects only and should not be used for operational forecasting.

Options 2 and 3

Option 2 or 3 time-critical applications can be tested with the  IFS cycle 41r2 test data retrieved from MARS or received in Dissemination

EMOSLIB

EMOSLIB 000420 provides preliminary support for octahedral grids. This includes full support for interpolation of input octahedral grids to any of the previously supported grids as well as spherical transforms to the new octahedral grids.

For more information please check version 000420 changes..

GRIBEX: functionality superseded by GRIB_API.
ABORTX : Routine GRIBEX has requested program termination. 

GRIB API

Preliminary support for the octahedral grid is provided from grib_api 1.14.2. Users of the grib_find_nearest routine are strongly advised to upgrade to at least this version. 

Older versions of grib_api can decode the octahedral grid successfully but users are advised to use at least grib_api version 1.12.3.

...

The MARS language changes described above apply also to the web based dissemination requirements tool.

Two specific ENS Calibration / Validation forecasts (MARS class="OD", STREAM=ENFO, class="CV") will be discontinued with the implementation of IFS cycle 41r2. Any dissemination requirements requesting these products will be taken out of dissemination streams by ECMWF on the day of 41r2 cycle implementation.

ENS variable resolution overlap products (MARS class="OD", STREAM=EFOV) provided currently from day 9 to 10 will also be discontinued. Thus, all EFOV requirements will be taken out of dissemination streams by ECMWF on the day of 41r2 cycle implementation.

New overlap data, provided from day 14 to 15 for ENS Extended run, will have to be requested by users themselves once 41r2 cycle has been implemented.

Since there is no ENS resolution change Day 0-15 in the IFS cycle 41r2, requesting field resolution truncation in dissemination for Day 0-10 is no longer needed. The MARS keyword RESOL=N160 was used to truncate products from ENS Day 0-10 to the N=160 original reduced Gaussian grid of ENS Day 11-16 prior to interpolation to regular latitude-longitude grids. Users are strongly advised to remove truncation request from their dissemination requirements.  

Time-critical applications

Information will be provided at a later date for users wishing to test their time-critical option 1, 2 or 3 applications with the higher resolution data .

Availability of IFS cycle 41r2 test data

...

Anchor
test_dissemination test_dissemination

Test data in dissemination

Since 8 December 2015, IFS cycle 41r2 test Dissemination data will be is available through the test dissemination system, close to real time, from 8 December 2015. Currently . Up to 14 January 2016, IFS cycle 41r2 dissemination products are were based on users' operational dissemination requirements, backwards compatible with the IFS cycle 41r1.

Users will be notified via these web pages when additional, On 14 January 2016, additional IFS cycle 41r2-specific dissemination functionality becomes was made available. Users will be able to can request dissemination products from a new 0.1 degree base grid from the high resolution forecast as well as 0.2 degree based grid from the ENS (days 1 to 15) and 0.4 degree based grid from the ENS Extended run. In addition, 0.125 degree based grid products will be made are available from the global in- coupled wave model, 0.25 degree based products from the ENS-WAM and 0.1 degree based products from the HRES-SAW model. Users will can also be able to request data on the octahedral grid.

...

The IFS cycle 41r2 test products are available on the ECPDS as version number 69. The test products will be are generated daily, shortly behind real-time from both the 00UTC and 12UTC runs and based on the IFS cycle 41r2 test data for HRES, ENS, WAM, ENS_WAM and HRES-SAW.

...

• Internet transfers: 193.61.196.104 (ecpds-xma.ecmwf.int) 193.61.196.105 (ecpds-xmb.ecmwf.int)
• RMDCN transfers: 136.156.8.132 (mspds-dm4.ecmwf.int)

Should you require any assistance with IFS cycle 41r2 test dissemination products, please contact Unknown User (maj).Technical details on how to update the dissemination requirements to request new IFS cycle 41r2 data, like octahedral grid, will be provided in due course (target mid Januarycontact Unknown User (maj).

Anchor
test_eccharts test_eccharts

Graphical display of IFS cycle 41r2 test data using ecCharts

...

IFS cycle 41r2 test data is accessible via the ecCharts layers menu, identified by the label "esuite 0069" as shown in the screenshot on the left. They can be displayed as any other layers of ecCharts, and they can be saved in the Dashboard, as seen in the screenshot on the right.

...