Atmosphere (대기)

Korean Meteorological Society (한국기상학회)
권호 표지
DOI QR코드

DOI QR Code

Optimization of the Vertical Localization Scale for GPS-RO Data Assimilation within KIAPS-LETKF System

KIAPS 앙상블 자료동화 시스템을 이용한 GPS 차폐자료 연직 국지화 규모 최적화

  • 조영순 (한국형수치예보모델개발사업단) ;
  • 강지순 (한국형수치예보모델개발사업단) ;
  • 권하택 (극지연구소)
  • Received : 2015.04.23
  • Accepted : 2015.08.31
  • Published : 2015.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

Korea Institute of Atmospheric Prediction System (KIAPS) has been developing a global numerial prediction model and data assimilation system. We has implemented LETKF (Local Ensemble Transform Kalman Filter, Hunt et al., 2007) data assimilation system to NCAR CAM-SE (National Center for Atmospheric Research Community Atmosphere Model with Spectral Element dynamical core, Dennis et al., 2012) that has cubed-sphere grid, known as the same grid system of KIAPS Integrated Model (KIM) now developing. In this study, we have assimilated Global Positioning System Radio Occultation (GPS-RO) bending angle measurements in addition to conventional data within ensemble-based data assimilation system. Before assimilating bending angle data, we performed a vertical unit conversion. The information of vertical localization for GPS-RO data is given by the unit of meter, but the vertical localization method in the LETKF system is based on pressure unit. Therefore, with a clever conversion of the vertical information, we have conducted experiments to search for the best vertical localization scale on GPS-RO data under the Observing System Simulation Experiments (OSSEs). As a result, we found the optimal setting of vertical localization for the GPS-RO bending angle data assimilation. We plan to apply the selected localization strategy to the LETKF system implemented to KIM which is expected to give better analysis of GPS-RO data assimilation due to much higher model top.

Keywords

References

  1. Anthes, R. A., 2011: Exploring Earth's atmosphere with radio occultation: contributions to weather, climate and space weather. Atmos. Meas. Tech., 4, 1077-1103, doi:10.5194/amt-4-1077-2011.
  2. Anthes, R. A., C. Rocken, and Y.-H. Kuo, 2000: Applications of COSMIC to meteorology and climate. Terr. Atmos. Ocean. Sci., 11, 115-156. https://doi.org/10.3319/TAO.2000.11.1.115(COSMIC)
  3. Anthes, R. A., and Coauthors, 2008: The COSMIC/FORMOSAT-3 Mission: Early Results. Bull. Amer. Meteor. Soc., 89, 313-333. https://doi.org/10.1175/BAMS-89-3-313
  4. Anlauf, H., D. Pingel, and A. Rhodin, 2011: Assimilation of GPS radio occultation data at DWD. Atmos. Meas. Tech., 4, 1105-1113, doi:10.5194/mat-4-1105-2011.
  5. Cucurull, L., and J. C. Derber, 2008: Operational implementation of COSMIC observations into NCEP's global data assimilation system. Wea. Forecast., 23, 702-711. https://doi.org/10.1175/2008WAF2007070.1
  6. Cucurull, L., J. C. Derber, and R. J. Purser., 2013: A bending angle for- ward operator for global positioning system radio occultation measurements. J. Geophys. Res. Atmo., 118, 14-28.
  7. Dennis, J. M., J. Edwards, K. J. Evans, O. Guba, P. H. Lauritzen, A. A. Mirin, A. St-Cyr, M. A. Taylor, and P. H. Worley, 2012: CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model. Int. J. High Perform. Comput. Appl., 26, 74-89. https://doi.org/10.1177/1094342011428142
  8. Eyre, J. R., 1994: Assimilation of radio occultation measurements into a numerical weather prediction system. Technical Memo., No. 199, ECMWF, Reading, UK.
  9. Healy, S. B., 2008: Assimilation of GPS radio occultation measurements at ECMWF, in: Proceedings of the GRAS SAF Workshop on Applications of GPSRO measurements, ECMWF, Reading, UK, 16-18 June 2008, 99-109.
  10. Healy, S. B., 2014: Use of GPS-RO data in NWP at ECMWF 2D operators, in: Fifth EUMETSAT ROM SAF user workshop on Applications of GPS radio occultation measurements, ECMWF, Reading, UK, 16-18 June 2014.
  11. Healy, S. B., and J. N. Thepaut, 2006: Assimilation experiments with CHAMP GPS radio occultation measurements. Quart. J. Roy. Meteor. Soc., 132, 605-623. https://doi.org/10.1256/qj.04.182
  12. Ho, S.-P., M. Goldberg, Y.-H. Kuo, C.-Z. Zou, and W. Schreiner, 2009a: Calibration of Temperature in the Lower Stratosphere from Microwave Measurements using COSMIC Radio Occultation Data: Preliminary Results. Terr. Atmos. Oceanic Sci., 20, doi:10.3319/TAO.2007.12.06.01(F3C).
  13. Hunt, B. R., E. Kostelich, and I. Szunyogh, 2007: Efficient data assimilation for spatiotemporal chaos: A local ensemble transform Kalman filter. Physica D, 230, 112-126, doi:10.1016/j.physd.2006.11.008.
  14. Jung, B.-J., J.-S. Kang, J. Kim, and Y. Jo, 2014: Preliminary result for KIAPS-LETKF system with real observations. Collection of abstracts for spring meeting of Korean Meteorological Society, 11-12.
  15. Kang, J.-S., and J. Park, 2013: Development of KIAPS Ensemble Data Assimilation System. KIAPS Tech. Note., 2013.
  16. Kang, J.-S., B.-J. Jung, H.-W. Jun, J.-H. Kim, S. Shin, Y. Jo, and H. Kwon, 2014: Progress and Plans of KIAPSLETKF:4D-LETKF, Radiance Data Assimilation, and Implementation to KIAPS-FM. Fall meeting of K Korean Meteorological Society, 10, 103-105.
  17. Kuo, Y.-H., S. Sokolovskiy, R. A. Anthes, and F. Vandenberghe, 2000: Assimilation of GPS Radio Occultation Data for Numerical Weather Prediction. Terr. Atmos. Oceanic Sci., 11, 157-186. https://doi.org/10.3319/TAO.2000.11.1.157(COSMIC)
  18. Kursinski, E. R., G. A. Hajj, K. R. Hardy, J. T. Schofield, and R. Linfield, 1997: Observing Earth's atmosphere with radio occultation measurements using the global positioning system. J. Geophys. Res., 102, 23429-23465, doi:10.1029/97JD01569.
  19. Kwon, H., J.-S. Kang, Y. Jo, and J. H. Kang, 2015: Implementation of a GPS-RO data processing system for the KIAPS-LETKF data assimilation system. Atmos. Meas. Tech., 8, 1259-1273. https://doi.org/10.5194/amt-8-1259-2015
  20. Loiselet, M., N. Stricker, R. Anthes, J. Chang, J.-H. Tseng, and B. Wang, 2000: GRAS-'Metop's GPS-based atmospheric sounder'. Bulletin 102, ESA, Darmstadt, Germany.
  21. Matsmura, T., J. C. Derber, J. G. Yoe, F. Vandenberghe, and X. Zou, 1999: The inclusion of GPS limb sounding data into NCEP's Global Data Assimilation System. NOAA/NCEP Office Note 426, 76 pp.
  22. Melbourne, W. G., E. S. Davis, C. B. Duncan, G. A. Hajj, K. R. Hardy, E. R. Kursinski, T. K. Meehan, L. E. Young, and T. P. Yunck, 1994: The application of spacebourne GPS to atmospheric limb sounding and global change monitoring. Jet Propulsion Laboratory, 147 pp.
  23. Phinney, R. A., and D. L. Anderson, 1968: On the radio occultation method for studying planetary atmospheres. J. Geophys. Res., 73, 1819-1827. https://doi.org/10.1029/JA073i005p01819
  24. Rennie, M. P., 2010: The impact of GPS radio occultation assimilation at the Met Office. Quart. J. Roy. Meteor. Soc., 136, 116-131, doi:10.1002/qj.521.
  25. Szunyogh, I., E. J. Kostelich, G. Gyarmati, E. Kalnay, B. R. Hunt, E. Ott, E. Satterfield, and J. A. Yorke, 2008: A Local Ensemble Transform Kalman Filter data assimilation system for the NCEP global model. Tellus, 60A, 113-130.