METEOAM (cnmc)

Mean zero-crossing wave period issue at step 0

Brief  description:

Due to the bug in the computation of  the second moment and the zero moment of the frequency spectrum (inconsistent diagnostic methods, truncation errors due to limited GRIB precision for the initial conditions) the values of the mean zero-crossing wave period  at step 0  are wrong . Affected data:

Recommendation:

Do not use the affected data.

SHNSM (sabm) 

Wrong peak wave period data

Brief  description:

Due to the bug in in the determination of the peak wave period values all available data can be affected.

Recommendation:

Do not use that parameter until the bug fix is implemented by the provider.

DWD (edzw)

U/V component problem Fixed on 2019-06-27 by re-processing and re-archiving all data Feb-Apr 2019

Description:

Problems were  identified in DWD operational runs where  a recalculation of  February to April period has been needed.

GRIB files advanced packing

Different GRIB2 packing than simple (cwao, rjtd, rksl data only)

Brief  description:

It has been discovered that input data from three providers are  using advanced (complex) GRIB packing. It might be useful to have smaller files generally but unfortunately it can create issues in some GRIB tools or for users as e.g. more CPU is needed to process data. For archiving purposes the hardware (tape) packing is used which is a better solution for number of reasons.

Recommendation:

Be aware that the centres below (have) used advanced packing. It does not affect data values at all but users can experience slower data processing in some scenarios.

DMI (ekmi)

U/V component sign problem  Fixed from 12Z 2019-07-16 onwards

Description:

U/V component sign is opposite than it should be. 

The wind speed discrepancy at day 5

Description:

The intensity fields (wind speed) exhibit some differences at day 5 comparing to other models. The explanation by the provider is that DMI gets access to ECMWF wind fields with a delay so large that  the previous forecast.must be used for the day 5.

To illustrate the problem see the comparison of 10 m wind forecasts from ECMWF and DMI for one case study (ecmf-10m-V ecmf-10m-WS ekmi-10m-V ekmi-10m-WS). Because of the delayed access to ECMWF winds the +120h ecmf data is thus compared to +132h

ekmi data (using the analysis 12h earlier) as explained by the provider.

Météo-France (lfpw)

10m wind issue  Fixed from 2019-10-01 onwards

Description:

There is a problem with 10m wind forecasts which can be illustrated by comparing wind speed and wind components from ECMWF and Meteo-France:

NCEP (kwbc)

Too high Peak wave period values in some grid points

Description:

Occasionally there are excessively high peak wave period values (>50s) affecting just single grid points.