Journal article
Four‐dimensional data assimilation experiments with International Consortium for Atmospheric Research on Transport and Transformation ozone measurements
Journal of Geophysical Research: Atmospheres, Vol.112(D12), pp.D12S15-n/a
06/27/2007
DOI: 10.1029/2006JD007763
Abstract
Ozone measurements by various platforms during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) operations in the summer of 2004 are assimilated into the STEM regional chemical transport model (CTM). Under the four‐dimensional variational data assimilation (4D‐Var) framework, the model forecast (background) error covariance matrix is constructed using both the so‐called NMC (National Meteorological Center, now National Centers for Environmental Prediction) method and the observational (Hollingworth‐Lönnberg) method. The inversion of the covariance matrix is implemented using truncated singular value decomposition (TSVD) approach. The TSVD approach is numerically stable even with severely ill conditioned vertical correlation covariance matrix and large horizontal correlation distances. Ozone observations by different platforms (aircraft, surface, and ozonesondes) are first assimilated separately. The impacts of the various measurements are evaluated on their ability to improve the predictions, defined as the information content of the observations under the current framework. In the end, all observations are assimilated into the CTM. The final analysis matches well with observations from all platforms. Assessed with all the observations throughout the boundary layer and midtroposphere, the model bias is reduced from 11.3 ppbv for the base case to −1.5 ppbv. A reduction of 10.3 ppbv in root mean square error is also seen. In addition, the potential of improving air quality forecasts by chemical data assimilation is demonstrated. The effect of assimilating ozone observations on model predictions of other species is also shown.
Details
- Title: Subtitle
- Four‐dimensional data assimilation experiments with International Consortium for Atmospheric Research on Transport and Transformation ozone measurements
- Creators
- Tianfeng Chai - University of IowaGregory R Carmichael - University of IowaYouhua Tang - University of IowaAdrian Sandu - Virginia Polytechnic Institute and State UniversityMichael Hardesty - NOAAPeter Pilewskie - NASA Ames Research CenterSallie Whitlow - University of New HampshireEdward V Browell - NASA Langley Research CenterMelody A Avery - NASA Langley Research CenterPhilippe Nédélec - Centre National de la Recherche ScientifiqueJohn T Merrill - University of Rhode IslandAnne M Thompson - NASA Goddard Space Flight CenterEric Williams - NOAA
- Resource Type
- Journal article
- Publication Details
- Journal of Geophysical Research: Atmospheres, Vol.112(D12), pp.D12S15-n/a
- DOI
- 10.1029/2006JD007763
- ISSN
- 0148-0227
- eISSN
- 2156-2202
- Number of pages
- 18
- Language
- English
- Date published
- 06/27/2007
- Academic Unit
- Civil and Environmental Engineering; Chemical and Biochemical Engineering; Nursing
- Record Identifier
- 9984004088702771
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