@inbook{81732,
  author = {ECMWF},
  title = {IFS Documentation CY50R1 - Part 2: Data Assimilation },
  abstract = {Chapter 1 Overview: the observation world<br />
Chapter 2 4D Variational assimilation&nbsp;<br />
Chapter 3 Tangent linear physics<br />
Chapter 4 Background terms<br />
Chapter 5 Observation-related processing (Jo)<br />
Chapter 6 Background errors<br />
Chapter 7 Gravity Wave Control<br />
Chapter 8 Diagnostics<br />
Chapter 9 Land-surface analysis<br />
Chapter 10 Analysis of ocean and sea-ice<br />
Chapter 11 Data flow},
  year = {2026},
  journal = {IFS Documentation CY50R1},
  chapter = {2},
  month = {06/2026},
  publisher = {ECMWF},
  url = {&nbsp;},
  doi = {10.21957/a77acfeae9},
}