1 / 18

Processing of COSMIC Radio Occultation Data and Cross-Center Comparison

This presentation discusses the processing of COSMIC radio occultation data and compares the results to UCAR processed data and ECMWF analyses. It also explores different processing options and their impact on accuracy.

gmichelle
Download Presentation

Processing of COSMIC Radio Occultation Data and Cross-Center Comparison

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Processing of COSMIC radio occultation data and cross-center comparison K. B. Lauritsen (DMI), M. E. Gorbunov (IAP), S. S. Leroy (HSEAS), A. V. Shmakov (IAP) Presentation based on paper: M. E. Gorbunov, A. V. Shmakov, S. S. Leroy, K. B. Lauritsen, Submitted to J. Atm. Ocean. Tech. (2010) OPAC-2010

  2. COSMIC data & ECMWF fields • Processed COSMIC data: • 20 days from each of the years 2007, 2008, 2009 (from 2009: data version 2009.2650 starting April 1); • Processing of atmPhs files with OCC (similar to GRAS SAF ROPP_PP software); • Results are compared to: • - UCAR processed data: atmPrf files (refractivities); • - ECMWF analyses (refractivities); OPAC-2010

  3. OCC processing and options State of the art Fourier integral operator code (CT2) ensures high accuracy (GO used above 25 km) SO: optimal linear combination based on initialization to ECMWF or 2-parameter fitted MSIS climatology Quality control based on L2-signal and SO-solution: Q = QL2 + QSO Cutoff of u(t): at SLTA = -250 km Radio-holographic (RH) filtering: - phase: no; CT-amplitude: yes - full RH filtering results in positive bias from suppression of large BAs and MP structures in wide-band signal tails [Sokolovskiy, 2009] OPAC-2010

  4. OCC 2009: #occ About half the profiles penetrate down to 1 km OPAC-2010

  5. OCC-ECMWF: 2007 REF OPAC-2010

  6. OCC-ECMWF: 2008 REF OPAC-2010

  7. OCC-ECMWF: 2009 REF OPAC-2010

  8. OCC-UCAR: 2009 REF OPAC-2010

  9. Zoom on tropical bias, 2009 data OPAC-2010

  10. Tropics (0-300), with RH-filtering RH filtering: phase: yes CT-amplitude: yes OPAC-2010

  11. Tropics (0-300), with no RH-filtering RH filtering: phase: no CT-amplitude: no OPAC-2010

  12. OCC-UCAR: 2009 REF, alternative options Cutoff at SLTA = -150 km RH filtering: phase: yes 2-parameter MSIS fit OPAC-2010

  13. OCC-UCAR: 2009 REF, optimal options Cutoff at SLTA = -250 km RH filtering: phase: no Initialization to ECMWF OPAC-2010

  14. OCC-ECMWF differences : 2007, 2008, 2009 Change in ECMWF cycle 32r3 in 2008: i) COSMIC RO assimilated to surface ii) updated convection and entrainment physics OPAC-2010

  15. OCC-UCAR: 2009 raw BA OPAC-2010

  16. OCC-UCAR: 2009 Tdry OPAC-2010

  17. Results Comparison of OCC and UCAR refractivities for three different years (2007, 2008, 2009) Tropics: - relative difference is smaller than 0.1% for 2-30 km (and smaller than 0.03% for 9-25 km) - 0.2% bias below 1 km, due to different cutoff and filtering OPAC-2010

  18. fin OPAC-2010

More Related