Adam Clayton

Adam works on coupled variational/ensemble data assimilation.

Areas of expertise:

  • Variational data assimilation
  • Initialization and gravity-wave control

Current activities

Adam is a senior scientist whose current work focuses on ways to incorporate information from the Met Office ensemble prediction system MOGREPS into the data assimilation systems used to produce "best guess" forecasts. One of the key requirements in a data assimilation system is to characterise the errors in the "background" forecasts that are combined with observations to produce updated estimates of the atmosphere's state. Typically, these errors are specified via rather basic models, whose parameters are then obtained via climatological statistics. In reality, however, we know that the structure of forecast errors is complex and constantly changing, depending on where atmospheric instabilities have occurred in recent days, and how well their affects have been captured by the observation network. Estimation of forecast errors is the domain of ensemble forecasting, so it is natural to ask whether information from ensemble forecasts can be used to improve the modelling of forecast errors within the data assimilation system. Adam is currently working on a "hybrid" data assimilation system that does just this; blending the ensemble forecasts with the standard climatological estimates of the background error. By doing so, it is hoped that the nonlinear aspects of the atmosphere will be better captured, improving our forecasts in cases where such effects are important; for example, the cases of rapid cyclogenesis that account for much of the severe weather affecting the UK.

Career background

Adam joined the Met Office in 1993, and was heavily involved in the development of the Met Office 3D-Var and 4D-Var data assimilation systems, which now form the basis of operational weather forecasting at the Met Office. A particular focus was the development of schemes for controlling the "gravity-wave noise" that results from the approximations typically used within analysis schemes. If left unchecked, these spurious waves contaminate the forecasts, and can lead to problems assimilating later observations. To get around such problems, Adam developed the "Incremental Analysis Update" (IAU) and "Digital Filtering" schemes that are now used within the operational forecasting system. The control of gravity waves was also the subject of Adam's MSc dissertation, completed at the University of Reading with the support of the Met Office. In 2004, Adam moved to the Met Office Hadley Centre to join the UK-Japan Climate Collaboration (UJCC); a project to develop high-resolution climate models on the Earth Simulator supercomputer in Yokohama. On his return to the UK in 2008, he rejoined the Data Assimilation and Ensembles section.

Last updated: 10 April 2014