Data Assimilation

Providing an environment for the objective testing and evaluation of data assimilation techniques

Welcome to the homepage for the Data Assimilation Team. We were established within RAL's Joint Numerical Testbed in August 2006 to provide an environment for the objective testing and evaluation of state-of-the-art data assimilation techniques as applied in real-world numerical weather prediction applications. The DATC is also intended to complement the activities of the Developmental Testbed Center (DTC) by providing support, testing and evaluation of the data assimilation component of the Weather and Research Forecasting (WRF) modeling system.

An illustration of the role of the team as a bridge between WRF DA research and operational communities.
An illustration of the role of the team as a bridge between WRF DA research and operational communities.

The current scope of the Data Assimilation Team includes:

  • Data assimilation technique testing and evaluation (variational, ensemble, hybrid, nudging).
  • Data assimilation inter-comparison (GSI, WRF-Var, ...).
  • Observation System Experiments (OSEs).
  • Observation System Simulation Experiments (OSSEs).
  • Observation impact study.
  • Observation and background error estimation and tuning.
  • Data assimilation system maintenance and community support.
  • NWP system, including forecast and data assimilation system, pre-release/pre-operational extended testing.
  • NWP system sensitivity study (cycling vs cold-start, frequency, resolution, ...)
  • Data assimilation based validation and quality control.

 

The scope of the DATC is evolving as new applications appear.

DATC Research Highlights:

Observation Impact:

  • COSMIC refractivity
  • Radiance:
    • AMSU-A, AMSU-B
    • AIRS
    • SSMIS
  • Radar

 

Technique:

  • First Guess at Appropriate Time (FGAT)
  • Multi-outer loop minimization and data rejection algorithm
  • Observation error tuning
  • Background error tuning

 

System:

  • WRF-VAR
  • GSI
  • Ensemble
  • Hybrid Var/Ensemble

 

Projects

The DATC was initiated as a joint collaboration between NCAR and the Air Force Weather Agency (AFWA) in 2006. Since then, the DATC has become an international effort supported by AFWA, NCAR's Antarctic Mesoscale Predictions System (AMPS), the Korean Meteorological Administration (KMA) and Taiwan Civil Aeronautics Administration (CAA). Testbeds have been built to test and evaluation data assimilation components in various applications. Details of these projects can be found in the projects list to the right of this page.

 

DATC Sponsors

U.S. Air Force Weather Agency (AFWA) NSF Office of Polar Programs (OPP) Civil Aeronautics Asministration (CAA) (Taiwan) Korea Meteorological Administration

 

 

Presentations

Applications of WRF Data Assimilation System at the NCAR Data Assimilation Testbed Center, The 9th WRF Users' Workshop, June 24-27, 2008, Boulder, Colorado (pdf)

Related links

Forecast and Data Assimilation Systems:

Collaborators:

Data Assimilation