IFS Cycle 45r1 is an upgrade with many scientific contributions, including changes in data assimilation (both in the EDA and the 4DVAR), in the use of observations, and in modelling. The new cycle only includes meteorological changes; there are no technical changes, e.g. new resolutions.
The page will be updated as required. It was last changed on 21.03.2018.
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.
The planned timetable for the implementation of the cycle 45r1 is as follows:
Date | Event |
---|---|
21.03.2018 | Initial Publication |
April 2018 | Initial announcement, with test data in MARS |
May 2018 | Availability of test data in dissemination |
5 June 2018 | Expected date of implementation |
The timetable represents current expectations and may change in light of actual progress made.
The Alpha testing of cycle 45r1 will continue and the cycle is being passed to the Forecast Department to start the Beta testing.
Assimilation
Observations
Retuning of the radiosonde observation error, and introduction of a scheme to account for radiosonde drift;
Introduction of temperature bias correction of old-style AIREP observations; aircraft temperature varBC predictor upgraded to a three predictor model (cruise, ascent, descent); reduced thinning of aircraft data;
Assimilation of JASON-3 and Sentinel-3A altimeters, and use of new altimeters for wave data assimilation;
Model
The following evaluation of the new cycle is based on the alpha testing. Scorecards will be made available based on the beta testing phase.
The new cycle leads to improvements in HRES upper-air fields. Verified against the model analysis, a positive signal is seen throughout the troposphere for most parameters, except temperature in the lower troposphere at shorter ranges. The latter is mainly a result of changes to the analysis, as confirmed by corresponding neutral results against observations. Upper-air improvements are more pronounced in the tropics, especially for wind and temperature. Verified against observations, upper-air changes are overall positive in the tropics except for relative humidity, and neutral to slightly positive in the extratropics. Upper-air results for the ENS verified against analysis are mostly positive in the tropics but more neutral in the extratropics. The negative signal for temperature in the lower troposphere at shorter lead times is again mainly due to changes in the analysis. Against observations, results are mostly negative in the extratropics at early lead times and significantly positive in the tropics, with the exception of relative humidity at 700hPa. The negative impact in the extratropics is partly due to a slight reduction in ensemble spread associated with the transition to a physically more realistic SPPT scheme. Whether or not this reduced spread is genuinely detrimental depends on whether observation errors are taken into account in the verification which has not been done routinely so far. Experimental verification against radiosonde data that takes observation error into account indicates that a large fraction of the negative ENS results disappear or become statistically non-significant.
There is an overall improvement in 2m temperature both in the HRES and ENS, particularly for Europe. 2m humidity is largely neutral for HRES, but positive for ENS, particularly in the tropics. 10 m wind speed is largely neutral in the HRES and slightly negative in the ENS. Precipitation in the HRES is improved in terms of categorical verification (e.g. SEEPS), and near-coastal precipitation in warm-rain dominated situations is significantly improved due to changes in the cloud physics. However, these changes also lead to more activity at higher precipitation rates in active regions such as the East Asian monsoon, and as a result error measures such as RMSE or CRPS (for the ENS) are increased. The negative signal for significant wave height against analysis is a result of changes to the analysis from a large increase in observation usage, and verification against observations (buoys) shows the results are neutral for both HRES and ENS,
Changes in scores for the monthly system are generally positive across the range of parameters, with significance in week 1 for tropical winds. The only indication of a degradation is precipitation in the tropics with a consistent negative signal across all 4 weeks. There is an indication of a positive effect on skill across all parameters in the European domain. The MJO Index was significantly underspread, but changes in 45r1 to the SPPT scheme have brought the spread and error in close agreement throughout the 30 day forecast range. The underestimation of the MJO Index amplitude error has been significantly improved throughout the forecast.
The GRIB model identifiers (generating process identification number) for cycle 45r1 will be changed as follows:
GRIB 1 Section 1 Octets | GRIB 2 Section 4 Octets | grib_api key | Component | Model ID | |
---|---|---|---|---|---|
Old | New | ||||
6 | 14 | generatingProcessIdentifier | Atmospheric model | 148 | 149 |
Ocean wave model | 113 | 114 | |||
HRES stand-alone ocean wave model | 213 | 214 |
Extended output have been added in cycle 45r1, including precipitation rates, CAPE indices and a total lighting flash density.
paramId | Shortname | name | Description | units | GRIB edition | Component | Test data available | Dissemination | ecCharts | Proposed for Catalogue |
---|---|---|---|---|---|---|---|---|---|---|
228050 | litoti | Instantaneous total lightning density | Total lightning flash density (instantaneous) | flashes km-2 day-1 | 2 (TBC) | HRES / ENS | ![]() | ![]() | TBC | ![]() |
228051 | litota | Averaged total lightning density since previous post-processing | Total lightning flash density (averaged between consecutive post-processing time steps) | flashes km-2 day-1 | 2 (TBC) | HRES / ENS | ![]() | ![]() | TBC | ![]() |
228057 | litota3 | Averaged total lightning flash density over the past 3 hours | Averaged total (cloud-to-ground + intra-cloud) lightning flash density over the past 3 hours. | flashes km-2 day-1 | 2 | HRES / ENS | ![]() | ![]() | TBC | ![]() |
228058 | litota6 | Averaged total lightning flash density over the past 6 hours | Averaged total (cloud-to-ground + intra-cloud) lightning flash density over the past 6 hours | flashes km-2 day-1 | 2 | HRES / ENS | ![]() | ![]() | TBC | ![]() |
260048 | tprate | Total precipitation rate | Total precipitation rate (instantaneous) | kg m-2 s-1 | 2 | HRES / ENS | ![]() | ![]() | TBC | ![]() |
228035 | mxcape6 | maximum CAPE in the last 6 hours | Maximum CAPE in last 6 hours | J kg-1 | 2 | HRES (TBC) / ENS | ![]() | ![]() | TBC | ![]() |
228036 | mxcapes6 | maximum CAPES in the last 6 hours | Maximum CAPESHEAR in last 6 hours | m2 s-2 | 2 | HRES (TBC) / ENS | ![]() | ![]() | TBC | ![]() |
Date | Reason for update |
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21.03.2018 |
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