The use of profiler data at ECMWF

The current status of the use of wind profiler data at ECMWF is documented. The operational global four-dimensional variational data assimilation system of the atmosphere uses hourly profiles of horizontal wind in real time from the US profiler network. This observing system provides some original information about the performance of the data assimilation. Data from the European CWINDE observing network has been monitored and found to be good enough for future operational use subject to the appropriate data selection. The reporting of wind observations at high resolutions raises some concerns about the performance of the data assimilation system and a theoretical analysis of the problem is attempted.