As was the case for the old JCOMM inter-comparison, ECMWF is committed to provide the actual match-up (collocation) data of observations and forecasts, as well as the original raw observations data on a monthly basis on a password protected ftp server:

  • host:
  • password: <see in the email sent to the contributors (this page content is identical to that email)>

where files

LCWFV_collocations_yyyymm.tar.gz  are the match-up (collocation) data 


raw_hourly_data_yyyymm.gz are the raw observations.

  • LCWFV_collocations_yyyymm.tar.gz contain 3 files, SWH_data*, PP1D_data*, V10_data* for significant wave height (SWH), peak wave period (PP1D) and 10m wind speed (V10)
  • The data column corresponding to each participating centre is referred to using its corresponding grib code, as given in
  • All dates are the actual valid dates (the dates for which the forecasts are valid) and the forecast steps are given in hours
  • Missing data are indicated by the value 99.99
  • Units are SHW: m, PP1D: s, V10: m/s
  • The files raw_hourly_data_yyyymm.gz are the same as those exchanged in the old system

Please note that these files are not to be re-distributed further. We intend to upload them as soon as possible following the end of each month, but the procedure by which different observation data sets are assembled and quality controlled is not yet fully automated, hence a certain delay (currently on the order of 1 month). For those who have contributed observations, please continue to do so. In the longer term it could be beneficial to push your data directly to the GTS. We will review the data usage on a regular basis.