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Using MODIS and AIRS for cloud property characterization

Using MODIS and AIRS for cloud property characterization. Jun Li @ , W. Paul Menzel # , Steve Ackerman @ , Chian-Yi Liu @ , and Allen Huang @ @Cooperative Institute for Meteorological Satellite Studies (CIMSS) Space Science and Engineering Center University of Wisconsin-Madison

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Using MODIS and AIRS for cloud property characterization

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  1. Using MODIS and AIRS for cloud property characterization Jun Li@, W. Paul Menzel#,Steve Ackerman@, Chian-Yi Liu@,and Allen Huang@ @Cooperative Institute for Meteorological Satellite Studies (CIMSS) Space Science and Engineering Center University of Wisconsin-Madison #Center for Satellite Applications and Research (STAR) NOAA/NESDIS Jun.Li@ssec.wisc.edu MODIS Science Team Meeting 4 – 6 January 2006 Radisson Plaza Lord Baltimore Hotel, Baltimore

  2. Spatial resolution Cloud masking New and Improved products are found combinations of MODIS and AIRS data MODIS AIRS Spectral resolution Sounding capability

  3. Why MODIS/AIRS synergy ? • AIRS provides sounding capability but is influenced by clouds during to large footprint size (13.5 km at nadir), MODIS clear radiances can help AIRS cloud-clearing (removal of clouds) • MODIS provides less cloud microphysical information during night, AIRS provides cloud microphysical properties for semi-transparency clouds but needs MODIS masks (cloud mask and cloud phase mask) for sub-pixel cloud characterization.

  4. How MODIS/AIRS synergy ? • Use MODIS masks (cloud mask, cloud phase mask, and cloud classification mask) for AIRS sub-pixel cloud characterization (Li et al. 2004) • Use combined MODIS and AIRS for cloud property (cloud-top pressure, optical thickness, particle radius) retrieval during night • Use MODIS for AIRS cloud-clearing in partial cloud cover • Use MODIS clear radiances within AIRS sub-pixel plus AIRS cloudy radiances to construct AIRS clear column radiance spectrum • Use MODIS clear radiances for QC on MODIS/AIRS cloud-cleared radiances and AIRS sounding retrieval

  5. AIRS sub-pixel cloud detection and characterization using MODIS (Li et al. 2004a). • Use MODIS cloud mask (1 km) for AIRS single field-of-view (SFOV) clear mask • Use MODIS cloud phase mask (1 km) for AIRS SFOV cloud phase mask • Use MODIS cloud classification mask (1 km) for AIRS SFOV cloud classification mask Aqua MODIS RGB Natural Color; 17 September 2003: Hurricane Isabel

  6. AIRS clear coverage Clear Cloudy MODIS confident clear pixels are counted for AIRS clear coverage ! MODIS 1 km cloud mask

  7. Unknown Mixed Phase Ice Clouds Water Clouds Clear AIRS cloud phase mask with 13.5 km resolution (mixed phase clouds appear frequently !) MODIS cloud phase mask with 1 km spatial resolution

  8. F3 F2 F1 AIRS Window BT(K) Water Land L. Cld Mid Cld L. Cld H. Cld H. Cld Mid Cld Mid. Cld MODIS 1km classification mask superimposed to the AIRS footprints of the study area. The MODIS classification mask gives the cloud layer information with each AIRS footprint.

  9. 1DVAR during daytime: MODIS cloud products are used as background Observed AIRS Radiance Measurements Background Information from MODIS Fast Cloudy Radiative Transfer Model CTP: Cloud-Top Pressure ECA: Effective Cloud Amount CPS: Cloud Particle Size COT: Cloud Optical Thickness at 0.55µm COT and CPS: 790 – 1130 cm**-1 CTP and ECA: 670 – 790 cm**-1 Minimum Residual (MR) during nighttime

  10. F1: CTP=251, COT=0.34 F2: CTP=248, COT=1.18 Wavenumber (cm**-1) F1 F2 AIRS BT(K) @ 901.69 cm-1 1km MODIS classification mask

  11. F3: Thick ice clouds 1km MODIS classification mask superimposed to AIRS footprints AIRS BT(K) @ 901.69 cm-1

  12. pc=258 mb, effective cloud amount =0.70 De=33.9 µm,tc=1.62 Microphysical information

  13. AIRS window BT image

  14. AIRS cloud-top pressure retrieval (MODIS is used for AIRS cloud detection)

  15. AIRS cloud optical thickness retrieval (MODIS is used for AIRS cloud phase detection)

  16. MPACE: Mixed Phase Artic Cloud Experiment Granule 223, 17 October 2004 AIRS CTH (m) Box A Barrow BT (K) MODIS are used for AIRS cloud detection and cloud phase detection !

  17. CTP comparison with Lidar AIRS time is 22:17:32 AIRS CTH=7.6 km RAOB: T and Td

  18. AIRS OD=1.44 Vertical Layers AIRS Effective Radius=38.6 um AIRS time = 22:17:32 UTC

  19. Using MODIS for AIRS cloud-clearing • MODIS and AIRS see the same IR spectral regions • Using MODIS for AIRS cloud-clearing is relevant to GOES-R ABI/HES retrieval (no microwave data available on GOES-R) • MODIS can be used for QC on AIRS cloud-cleared radiances and sounding retrieval

  20. Aqua MODIS IR SRF Overlay on AIRS Spectrum Direct spectral relationship between IR MODIS and AIRS provides unique application of MODIS in AIRS cloud_clearing !

  21. Optimal imager/sounder cloud-clearing Methodology (Li et al. 2005; IEEE Trans. On Geoscience and Remote sensing, June issue). 3 5 8 7 2 • CCR is obtained on single footprint basis (3 by 3 box moves by single footprint • MODIS clear radiances are used for QC 1 6 4 N* is solved from 9 MODIS band (22, 24, 25, 28, 30, 31, 32, 33, 34) are used

  22. AIRS clear (13.5 km) AIRS clear + CC-S (13.5 km) MODIS clear (1 km)

  23. AIRS clr + CC BT ( convolved to MODIS 6.7 um band) AIRS granule 184 of Sept 24, 2004

  24. AIRS BT (All) AIRS BT (Cloud-Cleared) AIRS BT (Clear Only)

  25. Summary • MODIS high spatial resolution masks (cloud mask, cloud phase mask and classification mask) are perfect for AIRS sub-pixel cloud characterization • MODIS/AIRS combination provides good cloud properties (cloud-top pressure, optical thickness, particle radius) during night time • MODIS can be used for AIRS cloud-clearing on single footprint basis

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