Research to Operations: Coupled Data Assimilation

Numerical Weather Prediction (NWP) at the Met Office and elsewhere have traditionally used integrated atmosphere-land models; however, over the last decade increasing evidence has emerged of the benefit of using an interactively coupled ocean model as part of the forecast system, particularly for more extreme events like tropical storms.
The team was created to lead the development and preparation for operational implementation, planned for 2021, of a fully coupled forecast system (including atmosphere, land, ocean and sea ice components) and to ensure the optimal combined use of observations in the various earth system components, with a particular focus on assimilation of land surface observations.

Key aims

• Deliver for operational implementation a global coupled numerical prediction system including an interactive ocean with ‘weakly coupled’ data assimilation (DA)
• Provide routine global ocean forecasts from a coupled system to the Copernicus Marine Service
• Maintain and improve the coupled prediction system by developing and testing the use of a higher resolution ocean component, use of ensemble information in the ocean DA, and more ‘strongly coupled’ assimilation approaches
• Ensure that land surface data assimilation is providing benefit for global and UK weather forecast systems and where possible other aspects of the land surface (e.g. hydrology)
• Enhance land surface DA approaches to more effectively exploit new and existing observations

Current activities

• Developing and testing the new global coupled atmosphere-ocean prediction system to ensure that scientific and technical performance is sufficient to replace the current NWP system in 2021
• Monitoring, maintaining and upgrading the operational coupled system delivering to users of the Copernicus Marine Service
• Delivering implementation of hourly soil moisture assimilation in the ‘Parallel Suite 43’ upgrade of the UK forecast system
• Working to improve the way satellite soil moisture observations from the ASCAT instrument on the Metop series of satellites are used for assimilation
• Developing a snow depth analysis to initialise the UK forecast system, making combined use of both satellite and ‘in situ’ observations
• Working to develop a land temperature analysis to help improve temperature forecasts
• Developing and maintaining scientific software to support land surface DA activities, including monitoring tools to enhance assessment of operational and trial performance