Second SRNWP Workshop on Mesoscale Verification

KNMI, De Bilt, The Netherlands

14 - 15 June 2004

Recommendations of the Workshop

GPS

At the final meeting of the "COST Action 716: GPS for NWP" which took place at KNMI on 1-3 December 2003, it has been decided to organise the dissemination of the ZTD in the frame of EUMETNET. The chairman of the "WG4: Planning for the Operational Phase" has been asked to liaise with EUMETNET/EUCOS for this important matter. The Co-ordinator will enquire about the stand of this action. (Remember that the main task of the EU-Project TOUGH is to study the scientific issues related to the assimilation of the ZTD in 3 and 4D-Var and not to deal with organisational matters).

Non-GPS precipitation observations

As KNMI is the Lead Centre for Verification, the Co-ordinator has asked the KNMI Director whether its NWS could take the responsibility of collecting the data of the climatological precipitation networks of the European NWS. The answer to this request has been given by KNMI during the workshop: KNMI has recognised that it is a necessity to set-up such a data base, but wants firstly to gain an exact picture of what is already operational today as it is known that precipitation data are already collected at different locations for different purposes. Examples:

- EU-Project ELDAS (but only the data of the participating NWS)

- ECMWF

- DWD for global precipitations, as a WMO mandate

- DWD also collects the COSMO daily climatological precipitations.

Reporting of the snow depth in the SYNOP

The knowledge of the amount of snow on the ground in important in NWP for two reasons:

- A soil covers with snow produces very different fluxes that the same soil without snow

- For verification purposes (snow versus rain).

It is often misleading in winter when no indication is given in the SYNOP message concerning the amount of snow on the ground: has the observer forgotten to report or has the snow melted?

The Co-ordinator will inform the Chairman of the PB-Obs about that matter and ask him to promote the habit in Europe or, better, to make compulsory that the snow depth must always be reported in the SYNOPs, with a zero when there is no snow.

Dissemination of the hourly SYNOP

At many locations in Europe, SYNOPs are generated each hour. But only the SYNOP of the so-called synoptic hours (00, 03, 06, ...) are disseminated to the other NWS.

The situation is improving. But the Coordinator has still to contact several NWS. In the next batch: Czech Republic, Denmark, Finland, Slovakia and Slovenia.

Velocity Azimuth Display (VAD) Radar Winds

The exchange of VAD Radar wind profiles should be improved in Europe. Not all the profiles are exchanged between the NWS. When a dissemination took place, it is often not comprehensive, but limited to bilateral agreements.

The Co-ordinator must first gain a concise picture of the present situation in Europe. He will for this purpose contact the Manager of the OPERA Programme to first have a concise picture of the situation in Europe. He will then - if it will seem appropriate to do so - liaise with EUMETNET/EUCOS to foster a more vigorous exchange.

Radial winds

Next to the exchange of the VAD profiles, dissemination of the radar radial winds should also be considered. For the same volume scan, this method would produce a much larger amount of data, but also richer information, as the wind for a given range and elevation will not longer be supposed homogeneous in speed and direction. The Co-ordinator will investigate this possibility.