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Advances in Atmospheric Sciences

, Volume 32, Issue 12, pp 1575–1582 | Cite as

Use of incremental analysis updates in 4D-Var data assimilation

  • Banglin ZhangEmail author
  • Vijay Tallapragada
  • Fuzhong Weng
  • Jason Sippel
  • Zaizhong Ma
Article
  • 170 Downloads

Abstract

The four-dimensional variational (4D-Var) data assimilation systems used in most operational and research centers use initial condition increments as control variables and adjust initial increments to find optimal analysis solutions. This approach may sometimes create discontinuities in analysis fields and produce undesirable spin ups and spin downs. This study explores using incremental analysis updates (IAU) in 4D-Var to reduce the analysis discontinuities. IAU-based 4D-Var has almost the same mathematical formula as conventional 4D-Var if the initial condition increments are replaced with time-integrated increments as control variables.

The IAU technique was implemented in the NASA/GSFC 4D-Var prototype and compared against a control run without IAU. The results showed that the initial precipitation spikes were removed and that other discontinuities were also reduced, especially for the analysis of surface temperature.

Keywords

data assimilation incremental analysis updates 4D-Var convergence 

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Copyright information

© Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Banglin Zhang
    • 1
    • 2
    Email author
  • Vijay Tallapragada
    • 2
  • Fuzhong Weng
    • 3
  • Jason Sippel
    • 1
    • 2
  • Zaizhong Ma
    • 4
  1. 1.I.M. System Group, Inc.College ParkUSA
  2. 2.NOAA NCEP Environmental Modeling CenterCollege ParkUSA
  3. 3.NOAA Center for Satellite Applications and ResearchCollege ParkUSA
  4. 4.Joint Center for Satellite Data AssimilationCollege ParkUSA

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