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With this cycle upgrade, the medium-range ensemble and its monthly extension see a major upgrade in the dynamical ocean model (NEMO): the resolution is increased from 1 degree and 42 layers to 0.25 degrees and 75 layers (ORCA025Z75). Furthermore, NEMO model version v3.4.1 with the interactive sea-ice model (LIM2) is implemented. The ocean and sea-ice components of the ENS initial conditions are provided by the new ocean analysis and reanalysis suite ORAS5, which uses the new ocean model and revised ensemble perturbation method.
The page will be updated as required. It was last changed on 0418.10.2016. Latest change: Meteorological impact of the new cycle and update to New model output parameters.
The next expected update to this page will is expected to be on 1024.10.2016.
For a record of changes made to this page please refer to Document versions .
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| Date | Event |
|---|---|
| 22 Sep 2016 | Initial announcement via e-mail to Member States contact points |
| Week beginning 17 24 Oct 2016 | Availability of test data in dissemination and confirmation of implementation date |
| 22 Nov 2016 | Expected date of implementation |
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The horizontal and vertical resolutions of the ocean model (NEMO v3.4.1) used by ENS is increased from 1 degree and 42 layers to 0.25 degree and 75 layers (ORCA025Z75). An interactive sea-ice model (the Louvain-la-Neuve Sea Ice Model - LIM2) is introduced so that sea-ice cover evolves dynamically. Previously it was persisted for 15 days; over the next 30 days of the forecast, it was relaxed towards the climatology of the previous 5 years.
Ocean initial conditions are taken from ORAS5 instead of ORAS4.
A global fix for tendency perturbations in the stochastic model error scheme SPPT to improve global momentum, energy and moisture conservation properties.
Technical changes
New model output parameters
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- The magnitude and direction of the wave energy flux that is responsible for the impact of the waves on coastlines and offshore structures.
- Significant wave height of all waves in six different period ranges to help with detection of low-frequency wave energy.
Parameters All the new output fields are available at the usual post-processing time steps . Further technical information is provided except where specified otherwise in the table.:
- HRES, HRES-WAM and HRES-SAW: analysis and forecast - 3-hourly from T+0 to T+144 and 6 hourly from T+150 to T+240.
- ENS and ENS-WAM: 3-hourly from T+0 to T+144 and 6 hourly from T+150 to T+360.
- ENS-extended and ENS-WAM-extended: 6 hourly from T+366 to T+1104.
Further technical information is provided in the table.
| paramId | shortName | name | description | units | GRIB edition | Component | Test data available | Dissemination | Proposed for Catalogue |
|---|---|---|---|---|---|---|---|---|---|
| 260109 | ceil | Ceiling | Cloud-base height relative to the ground. | m | 2 | HRES / ENS |  | TBC | TBC |
| 228046 | hcct | Height of convective cloud top | m | 1 | HRES / ENS | | TBC | TBC | |
| 228047 | hwbt0 | Height of zero-degree wet-bulb temperature | See 43r1 new parameters: Height of zero-degree (and one-degree) wet-bulb temperature | m | 1 | HRES / ENS | | TBC | TBC |
| 228048 | hwbt1 | Height of one-degree wet-bulb temperature | See 43r1 new parameters: Height of zero-degree (and one-degree) wet-bulb temperature | m | 1 | HRES / ENS | | TBC | TBC |
| 47 | dsrp | Direct solar radiation | Incident on a plane perpendicular to the sun's direction. This is an accumulated field. | J/m2 | 1 | HRES / ENS NB: only forecast | | TBC | TBC |
| 140112 | wefxm | Integral over all frequencies and directions of the product of the group speed and the two-dimensional energy wave spectrum. | W/ |
wefxm
h1012
Significant wave height of all waves with periods within the inclusive range from 10 to 12 seconds
| m | 1 | HRES-WAM / ENS-WAM / HRES-SAW |
| TBC | TBC |
| 140113 | wefxd | Wave energy flux mean direction | Spectral mean direction over all frequencies and direction of the product of the group velocity vector and the two-dimensional energy wave spectrum. | Degree true |
| 1 | HRES-WAM / ENS-WAM / HRES-SAW |
| TBC | TBC |
| 140114 |
h1012 | Significant wave height of all waves with periods within the inclusive range from |
| Significant wave height of all waves with periods within the inclusive range from |
| 10 to |
| 12 seconds, where the significant wave height is defined as 4 times the square root of the integral over all directions and all frequencies between 1/ |
| 12 and 1/ |
| 10 Hz of the two-dimension wave spectrum | m | 1 | HRES-WAM / ENS-WAM / HRES-SAW |
| TBC | TBC |
| 140115 |
| h1214 | Significant wave height of all waves with periods within the inclusive range |
| from12 to |
| 14 seconds | Significant wave height of all waves with periods within the inclusive range from |
| 12 to |
| 14 seconds, where the significant wave height is defined as 4 times the square root of the integral over all directions and all frequencies between 1/ |
| 14 and 1/ |
| 12 Hz of the two-dimension wave spectrum | m | 1 | HRES-WAM / ENS-WAM / HRES-SAW |
| TBC | TBC |
| 140116 |
| h1417 | Significant wave height of all waves with periods within the inclusive range from |
| 14 to |
| 17 seconds | Significant wave height of all waves with periods within the inclusive range from |
| 14 to |
| 17 seconds, where the significant wave height is defined as 4 times the square root of the integral over all directions and all frequencies between 1/ |
| 17 and 1/ |
| 14 Hz of the two-dimension wave spectrum | m | 1 | HRES-WAM / ENS-WAM / HRES-SAW |
| TBC | TBC |
| 140117 |
| h1721 | Significant wave height of all waves with |
| periods within the inclusive range from 17 to 21 seconds | Significant wave height of all waves with periods within the inclusive range from 17 to 21 seconds, where the significant wave height is defined as 4 times the square root of the integral over all directions and all frequencies between 1/21 and 1/17 Hz of the two-dimension wave spectrum | m | 1 | HRES-WAM / ENS-WAM / HRES-SAW | | TBC | TBC | ||
| 140118 | h2125 | Significant wave height of all waves with periods within the inclusive range from 21 to 25 seconds | Significant wave height of all waves with periods within the inclusive range from 21 to 25 seconds, where the significant wave height is defined as 4 times the square root of the integral over all directions and all frequencies between 1/25 and 1/21 Hz of the two-dimension wave spectrum | m | 1 | HRES-WAM / ENS-WAM / HRES-SAW | | TBC | TBC |
| 140119 | h2530 | Significant wave height of all waves with periods within the inclusive range from 25 to 30 seconds | Significant wave height of all waves with periods within the inclusive range from 25 to 30 seconds, where the significant wave height is defined as 4 times the square root of the integral over all directions and all frequencies between 1/30 and 1/25 Hz of the two-dimension wave spectrum | m | 1 | HRES-WAM / ENS-WAM / HRES-SAW | | TBC | TBC |
The following new variable resolution parameter is also provided in the ensemble forecast variable resolution overlap stream (STREAM=EFOV) at T+360 (STEP=360) from the Monday and Thursday runs of the ensemble forecast monthly extension.
| paramId | shortName | name | description | units | GRIB edition | Component | Test data available | Dissemination | Proposed for Catalogue |
|---|---|---|---|---|---|---|---|---|---|
| 230047 | dsrpvar | Direct solar radiation (variable resolution) | Variable resolution companion to dsrp. | J/m2 | 1 | ENS (STREAM=EFOV) | | TBC | TBC |
Meteorological impact of the new cycle
Comparison of scores between IFS cycle 43r1 and IFS cycle 41r2 for HRES can be found in the IFS Cycle 43r1scorecard.
Upper air
The new model cycle provides improved high-resolution forecasts (HRES) and ensemble forecasts (ENS) throughout the troposphere and lower stratosphere. In the extra-tropics, error reductions of the order of 0.5-1% are found for most upper-air parameters and levels. The improvement in the primary headline score for the HRES (lead time at which the 500 hPa geopotential anomaly correlation drops below 80%) is about 1 h.
Improvements are most consistently seen in verification against the model analysis. In the tropics, there is a small degradation (both against analysis and observations) of temperature near the tropopause in terms of root mean square error (RMSE) but not in terms of anomaly correlation. This is due to a slight cooling caused by a modification in the treatment of cloud effects in the vertical diffusion scheme, which overall leads to improved cloud cover. While there is a consistent gain for upper-air parameters on the hemispheric scale, some continental-scale areas, such as North America and East Asia, show statistically significant improvements only at some levels and for some parameters.
Increases in upper-air skill of the ENS are generally similar to the HRES, with a substantial gain for mean sea level pressure. The improvement in the primary headline score for the ENS (lead time at which the CRPSS of the 850 hPa temperature drops below 25%) is small (of the order of 0.5 h). The spread-error relationship is generally improved, partly due to reduced error and partly due to increased spread. For some parameters this improvement is quite significant, such as the 850 hPa wind speed in the tropics, where the under-dispersion is reduced by about 20% in the medium range.
Weather parameters and waves
The new model cycle yields consistent gains in forecast performance in the tropics and extra-tropics for total cloud cover, mostly due to a reduction of the negative bias in low cloud cover.
Changes in precipitation over land areas are small and overall neutral.
The increase in forecast skill for 2m temperature is most pronounced in the short and medium range, where it amounts to ~1% reduction of the RMSE in the northern hemisphere extra-tropics, and up to 2% over some land areas such as Europe and North America. In the tropics there is an increase of 0.5-1% in the RMSE for 2m temperature, connected to a slight increase of the overall cold bias at low latitudes. In the ENS there is a significant improvement in 2m temperature amounting to a 3% reduction in the continuous ranked probability score (CRPS) in Europe.
There is an increase of the RMSE of 2m humidity by about 1% in winter associated with the introduction of limited evapotranspiration when the uppermost soil layer is frozen. This change contributes to the improvements in 2m temperature.
10m wind speed shows error reductions of 0.5-1% over the ocean, leading to improvements in significant wave height and mean wave period, especially in the tropics and southern hemisphere. Over land areas, changes in 10m wind speed forecast skill are generally neutral to slightly positive.
Monthly forecast
Verification results show a modest positive effect on skill scores although the differences are not statistically significant. There is a substantial improvement in the skill scores for the Madden-Julian Oscillation (MJO), corresponding to a gain in lead time of 0.5-1 day at a forecast range of 4 weeks. Also, MJO spread is increased, bringing it closer to the RMSE. Verification of precipitation against analysis shows some degradation in the tropics which is not statistically significant, and a reduction of precipitation biases in the northwest Pacific.
Sea ice
The new cycle introduces a prognostic sea-ice model, leading to a significant reduction of the RMSE of sea ice fraction in the later medium range.
Technical details of the new cycle
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| GRIB 1 Section 1 Octets | GRIB 2 Section 4 Octets | grib_api key | Component | Model ID | |
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| Old | New | ||||
| 6 | 14 | generatingProcessIdentifier | Atmospheric model | 146 | 147 |
| Ocean wave model | 111 | 112 | |||
| HRES stand-alone ocean wave model | 211 | TBC212 | |||
Software
EMOSLIB
EMOSLIB 443 is needed to interpolate successfully the wave energy flux mean direction (wefxd) parameter introduced at IFS Cycle 43r1.
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Older versions of GRIB API can decode the IFS Cycle 43r1 products successfully but users are advised to use at least GRIB API version 1.14.5, which provides full support for the octahedral reduced Gaussian grid.
ecCodes
ecCodes version 2.0.0 provides full support for the new model output parameters introduced in IFS Cycle 43r1.
Availability of test data from the IFS Cycle 43r1 test suites
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Availability of test data from the release candidate testing stage in dissemination is expected to be announced during the week beginning 17 24 October 2016.
Document versions
| Date | Reason for update |
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| 19.09.2016 |
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| 22.09.2016 |
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| 04.10.2016 |
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| 18.10.2016 |
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