Following earlier posts on the Heavy Rainfall Alert tool, Peter Buchanan our Met Office forecasting service co-ordinator explains ‘what is best data!’

“The Met Office has had an operational numerical modelling capability for many years now. It runs a plethora of leading edge atmospheric, wave, ocean and specialised (e.g. air quality) models round the clock, for 365 days a year. This vast pool of data, as well as being used by the Met Office’s in-house experts, forecasters and consultants, is increasingly being made available to customers and end users.

The flood forecasting service has been working hard, mainly during the summer of 2013, to pull through the latest science and technical developments into the flood forecasting tools run by SEPA, in particular, the Grid-to-Grid (G2G) distributed hydrological model and coastal forecasting tools.

The various weather models are run at different times, at different resolutions, for different forecast periods and over different domains. So how do we choose the best model or models to use for a particular task and when is the best time to access these data? The Met Office has introduced the concept of ‘best data’ to simplify and optimise the application of these data for downstream users like the flood forecasting service.

Depending on the end user application, ‘best data’ can come in two ‘flavours’, best gridded data and best site specific data. For the most part, we use best gridded data for the purpose of flood forecasting. In essence, the best data process will combine the very latest and most appropriate data from a variety of models to produce a seamless data set from now to several days ahead. These raw data are integrated and further optimised by the Met Office’s Post Processing system which can add further value (e.g. further diagnostics and downscaling) and present it in a fixed high resolution grid. This Post Processing step helps future proof the data for end user systems as upstream configuration changes and science improvements will remain transparent, from the purely technical point of view.

The components and model make up of ‘Best Gridded Data’ (Copyright Met Office)

SEPA and Met Office systems and colleagues use these best data operationally to provide ‘best guidance’ in support of the flood forecasting service.

We can expect these ‘best data’ to help further improve forecasting service performance in the months and years ahead, particularly with the integration of high resolution probabilistic forecasts and the continuing development and refinement of the underpinning hydrological and meteorological models.”

Reference

Moseley, S. (2011), From Observations to Forecasts – Part 12: Getting the most out of model data. Weather, 66: 272-276. doi: 10.1002/wea.844.