1 / 22

Validation of CrIMSS sounding products of 20120515

Validation of CrIMSS sounding products of 20120515. Cloud contamination and angle dependency Zhenglong Li, Jun Li, and Yue Li University of Wisconsin - Madison. Outline. CrIMSS sounding products are affected by cloud contamination viewing angle Validation using ECMWF

kasia
Download Presentation

Validation of CrIMSS sounding products of 20120515

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. Validation of CrIMSS sounding products of 20120515 Cloud contamination and angle dependency Zhenglong Li, Jun Li, and Yue Li University of Wisconsin - Madison

  2. Outline • CrIMSS sounding products are affected by • cloud contamination • viewing angle • Validation using • ECMWF • CrIS radiance observations

  3. Pre-processing • VIIRS Cloud fraction • VIIRS Cloud fraction: collocation of VIIRS cloud mask geolocation with CrIS SDR geolocation • Cloud fraction is calculated for each CrIS FOV by counting the cloudy VIIRS pixels • Simulated CrIS radiance by SARTA • CrIMSS T/Q/Tskin • CrIMSS(IP) O3 • UW hyperspectral land surface emissivity

  4. CrIMSS overall quality flag - Ascending • Most of the retrievals are microwave only; thus may use CrIS spectrum validate CrIMSS sounding • Poor retrievals in high latitude areas

  5. CrIS 11-micron Tb - Ascending • Exclude FORs with poor retrievals • Compare with CrIS cloud fraction in next slide

  6. CrIS cloud fraction - Ascending • Exclude FORs with poor retrievals • Consistent with CrIS BT image in previous slide

  7. Tskin: CrIMSS-ECMWF - Ascending • Exclude FORs with poor retrievals • Land is more prone to emissivity uncertainty • Appears to be geographically related with clouds • Appears to be related to satellite viewing angle between 40 S and 40 N

  8. CrIS cloud fraction - Ascending • Exclude FORs with poor retrievals • Compare with T500 diff in next slide

  9. T 500 hPa: CrIMSS-ECMWF - Ascending • Exclude FORs with poor retrievals • Appears to be geographically related with clouds in southern hemisphere • Appears to be related to satellite viewing angle between 40 S and 40 N

  10. CrIMSS overall quality flag - Descending • Most of the retrievals are microwave only; thus may use CrIS spectrum validate CrIMSS sounding • Poor retrievals in high latitude areas

  11. CrIS 11-micron Tb - Descending • Exclude FORs with poor retrievals • Compare with CrIS cloud fraction in next slide

  12. CrIS cloud fraction - Descending • Exclude FORs with poor retrievals • Consistent with CrIS BT image in previous slide

  13. Tskin: CrIMSS-ECMWF - Descending • Exclude FORs with poor retrievals • Appears to be geographically related with clouds • Appears to be related to satellite viewing angle between 40 S and 40 N

  14. CrIS cloud fraction - Descending • Exclude FORs with poor retrievals • Compare with T500 diff in next slide

  15. T 500 hPa: CrIMSS-ECMWF - Descending • Exclude FORs with poor retrievals • Appears to be geographically related with clouds in southern hemisphere • Appears to be related to satellite viewing angle between 40 S and 40 N

  16. Clouds affect CrIMSS sounding - Ascending CF: cloud fraction Dash lines: bias Solid lines: STD Dev Clouds affect both precisions and accuracies, both T and Q Clouds affect precisions slightly more than accuracies Reference: ECMWF

  17. Clouds affect CrIMSS sounding - Descending CF: cloud fraction Dash lines: bias Solid lines: STD Dev Clouds affect both precisions and accuracies, both T and Q Clouds affect precisions slightly more than accuracies Reference: ECMWF

  18. Angle affects CrIMSS sounding - Ascending ANG: satellite viewing angle Dash lines: bias Solid lines: STD Dev Angle affects T more than Q Angle affects accuracies more than precisions All sky Reference: ECMWF

  19. Angle affects CrIMSS sounding - Descending ANG: satellite viewing angle Dash lines: bias Solid lines: STD Dev Angle affects T more than Q Angle affects accuracies more than precisions All sky Reference: ECMWF

  20. Angle affects CrIMSS sounding - Ascending An example of CrIS Tb spectrum in longwave CO2 band Upper atmosphere Lower atmosphere T angle dependency Combination of T/ε angle dependency Mean difference between CrIS obs and calc Reference: CrIS radiance obs Clear sky Ocean only

  21. Angle affects CrIMSS sounding - Descending An example of CrIS Tb spectrum in longwave CO2 band Upper atmosphere Lower atmosphere T angle dependency Combination of T/ε angle dependency Mean difference between CrIS obs and calc Reference: CrIS radiance obs Clear sky Ocean only

  22. Summary • CrIMSS sounding products agree with ECMWF reasonably well • Cloud presence slightly degrades the CrIMSS sounding products, both temperature and moisture, and both precisions and accuracies • CrIMSS temperature sounding products are slightly degraded with larger satellite viewing angle; more temperature bias • Suggest to add quality flags of cloud fraction and angle dependency

More Related