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Space and Time Multiscale Analysis System (STMAS)

STMAS is a next generation data assimilation system designed to improve forecasts and analysis and meets NOAA goals. STMAS is designed to improve EnKF/4DVAR. It uses a multigrid technique combining the advantages of EnKF and 4DVAR and reducing their limitations.

  • Limited ensembles (EnKF): STMAS applies EnKF at its finest multigrid level.
  • Nonlinearity (EnKF): Over each multigrid level, STMAS solves the nonlinear variational problem.
  • Inaccurate error covariance (4DVAR): At coarser grids, STMAS retrieves long waves from the observation network. Accurate covariance and Gaussian error distribution are not necessary.

STMAS Surface Analysis

Development of the STMAS Surface Analysis System for the FAA Aviation Weather Research Project to use for storm boundary detection began in 2004 with NOAA and FAA support. STMAS is designed to analyze high frequency surface data, such as ASOS with 5 to 15 minute reports, in high resolution (currently 2 km). The multigrid technique is extremely efficient. For example, a 5-km analysis of 10 state variables over the CONUS domain takes 4 minutes by a single 3.2GHz desktop computer.

Current users of STMAS include:

  • MIT for storm boundary detection.
  • CWB, Taiwan for surface reanalysis.
  • MDL and WFOs for nowcasting.
  • NMDIS, China for ocean SST reanalysis.
  • NCAR for wind energy applications.

STMAS Products

STMAS 3D/4D Analysis

The STMAS 3D/4D analysis prototype has been developed with NOAA/FAA/CWB support and through international collaboration. The current system is capable of analyzing all in-situ observation data, radar radial wind and SFMR data. The performance of STMAS analysis is currently being tested as initializations of WRF forecasts for case studies of hurricanes and tornados.

Future Developments

A multiscale analysis targeting improvement of forecasts with all data source and model constraints. An evaluation of STMAS comparing to NWS operational systems after completing basic development. Use of the STMAS or portion of STMAS to improve NWS operational data assimilation in the future.