@misc{79116,
  keywords = {workshop, data assimilation, flow-dependent},
  author = {R.N. Bannister and Mike Cullen},
  title = {A regime-dependent balanced control variable based on potential vorticity},
  year = {2007},
  month = {2007},
  url = {https://www.ecmwf.int/node/15669},
  language = {eng},
}