New Products from combined MODIS/AIRS Jun Li, Chian-Yi Liu, Allen Huang, Xuebao Wu, and Liam Gumley Cooperative Institute for Meteorological Satellite Studies Space Science and Engineering Center University of Wisconsin-Madison 1225 West Dayton Street, Madison, Wisconsin International EOS/NPP Direct Readout Meeting, 3 – 6 October 2005 Benevento, Italy

New products for IMAPP from combined MODIS/AIRS MODIS classification mask AIRS sub-pixel cloud detection products using MODIS data (Li et al. 2004a -JAM) Single FOV Cloud/Aerosol property products from AIRS radiances (Li et al. 2004b - JAM; 2005a - JAM) with the help of MODIS (cloud mask, cloud phase mask, cloud classification mask, etc.) AIRS cloud-clearing radiance products using multi-band MODIS clear radiances (Li et al. 2005b – IEEE TGARS)

AIRS sub-pixel cloud detection and characterization using MODIS (Li et al. 2004a - JAM). –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

MODIS 1 km cloud mask MODIS confident clear pixels are counted for AIRS clear coverage ! ClearCloudy AIRS clear coverage

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

AIRS Window BT(K) Water Land L. Cld Mid Cld L. Cld H. Cld H. Cld Mid Cld Mid. Cld F3 F2 F1 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.

Cloud property products from AIRS radiances (Li et al. 2004b - JAM; 2005a - JAM) with help of MODIS –MODIS cloud mask is used for AIRS SFOV clear/cloudy detection –MODIS cloud phase mask is used for AIRS SFOV phase determination –Cloud properties are retrieved from from AIRS radiances with a physical algorithm (Minimum Residual Method)

Fast Cloudy Radiative Transfer Model Observed HES Radiance Measurements CTP: Cloud-Top Pressure; ECA: Effective Cloud Amount at 10 wavenumbers CPS: Cloud Particle Size in diameter; COT: Cloud Optical Thickness at 0.55µm Minimum Residual (MR) algorithm for cloud property retrieval (Li et al. 2004b - JAM; 2005a - JAM ) Cost function clear cloudy COT, CPS (window region): 790 – 1130 cm-1 CTP and ECA (CO2 region): 670 – 790 cm-1

COT=10.0 COT=5.0 COT=1.0 COT=0.05

CPS=10 CPS=20 CPS=30 CPS=50

AIRS cm -1 1km MODIS classification mask superimposed to AIRS footprints F1: Thick ice clouds

F1: CTP=258, CPS=33.90, COT=1.62

AIRS window BT image over North America region

AIRS cloud-top pressure retrieval with help of MODIS cloud mask

AIRS cloud optical thickness retrieval with help of MODIS cloud mask and cloud phase mask

Validation of cloud properties Compare with MODIS natural color image Compare with MODIS classification results Ground measurements Lidar observation

MODIS/AIRS Spatial resolution: MODIS CTP: 5 km AIRS CTP: 13.5 km GOES CTP: 10 km

AIRS CTH (m) Barrow Box A MPACE: Mixed Phase Artic Cloud Experiment Granule 223, 17 October 2004

CTP comparison with Lidar AIRS time is 22:17:32 MODIS CTH=5.5 km; AIRS CTH=7.6 km

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

Desert Vs Dust aerosol Dust MODIS (BT11 - BT12) Desert AIRS window BT MODIS Natural color

Dust/aerosol Desert Low surface 8.9 um over desert Negative slope between 11 and 12 um Synergy of MODIS/AIRS is expected to improved aerosol/dust products which are useful for regional applications

Derive AIRS cloud-cleared radiances using MODIS/AIRS cloud-clearing algorithm MODIS multi-spectral IR clear radiances within AIRS sub-pixel are used for AIRS cloud-clearing on SFOV basis (Li et al. 2005b, IEEE-TGARS) MODIS clear radiances within AIRS sub-pixel are used for Quality Control (QC) on AIRS cloud- clearing

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 !

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

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

AIRS single FOV profile retrieval versus ECMWF analysis Cloud contaminated Cloud-cleared Clear neighbor Temperature Water Vapor Mixing Ratio

Contaminated by thin clouds !! Cloud-cleared (MODIS/AIRS) Temperature RMS difference between AIRS and ECMWF~ 250 thin cloud FOVs Clear Neighbor

1.There are potential new products from combined MODIS/AIRS, especially the SFOV cloud property products that include AIRS cloud mask, cloud phase mask, cloud layer information mask, etc. 2.AIRS SFOV cloud-cleared radiances will be derived using MODIS/AIRS cloud-clearing approach. 3.Efforts are also on deriving AIRS SFOV sounding products under both clear and cloudy skies with help of existing MODIS products. Summary