Radar Data for High Resolution NWP
Malcolm KITCHEN
Met Office, United Kingdom
Abstract
As nowcasting is progressively replaced by high resolution NWP over the next decade, then the radar data requirement will also change to meet the needs of assimilation. Weather radar networks represent one of the few observing systems which are capable of delivering data on a horizontal scale comparable to anticipated model resolutions. As a result the relative importance of the data source may increase. In anticipation of this expanded role in NWP, and the development of the high-resolution UK model in particular, a number of radar developments are under way in the UK:
- A new version of the radar site signal processor has been developed which enables recovery of radial
Doppler winds and supports measurements of absolute phase (necessary for recovery of refractivity).
- A collaborative project with Reading University is looking at the feasibility of retrieving 2D refractivity fields from
the UK weather radar network.
- Preliminary work towards the direct assimilation of reflectivity data. In particular the use of a system of quality control flags, and consideration of a different trade-off for NWP between spatial resolution and minimum detectable signal.
Modest expansion of the UK radar network in Eastern England is also in progress, which should hopefully offer some additional benefit to forecasting in France/Holland and Belgium.