@manual{1303132519950,
  author = {P.W. K{\r a}llberg},
  title = {Forecast drift in ERA-Interim},
  abstract = {In the ECMWF reanalyses, ERA-15, ERA-40 and ERA-Interim, model-generated estimates of the surface and top-of-atmosphere radiation fluxes, the turbulent fluxes and the hydrological fluxes at the surface were extracted from short-range forecasts. These estimates vary with the forecast length. This drift in the short-range forecasts can be a problem for users of monthly and climatic means. It is often referred to as {\textquoteright}spin-up{\textquoteright} or {\textquoteright}spin-down{\textquoteright}. Here the spin-up/spin-down properties of ERA-Interim will be summarized and compared to ERA-40. Since the comparisons are best seen directly in the maps and diagrams, the discussions will be brief. It will be seen that the conflicting requirements of {\textquoteright}stable forecasts{\textquoteright} and {\textquoteright}close to the analysis time{\textquoteright} can not always be met.},
  year = {2011},
  journal = {ERA Report Series},
  number = {10},
  pages = {9},
  month = {2011},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  language = {eng},
}