Measurements
MODIS, Terra and Aqua
Local Observation Time and Length of Data Record
10:30 AM and 10:30 PM ; 2001–2009,
1:30 AM and 1:30 PM ; 2003–2009
Spatial Resolution
1 km (detection, COD, CRE, CWP, phase retrieval), 5 km (CP, CT, CEM retrieval)
Cloud Detection
multi-spectral IR/NIR/VIS (16 channels)+ time-space variances
Retrieval Methodology
CP, CEM → CT, cloud phase (water/ice), COD, CRE, CWP
MODIS Science Team uses spectral testing to determine cloud amount, "CO2 slicing" to determine cloud pressure
and emissivity and a Look-Up Table approach using solar reflectance channels to retrieve cloud optical depth
and effective particle radius.
Ancillary Input
NCEP GDAS profiles
16 day spectral surface albedo climatology
radiative transfer+particle model
mixed particle habits for ice
References
Ackerman, S. A., K. I. Strabala, W. P. Menzel, R. A. Frey, C. C. Moeller, and L. E. Gumley, 1998:
Discriminating Clear-sky from Clouds with MODIS. J. Geophys. Res., 103, D24, 32,141.
Frey, R. A., S. A. Ackerman, Y. Liu, K. I. Strabala, H. Zhang, J. Key and X. Wang, 2008:
Cloud Detection with MODIS, Part I: Recent Improvements in the MODIS Cloud Mask, J. Atmos. Oceanic Tech., 25, 1057-1072.
Menzel, W. P., R. A. Frey, H. Zhang, D. P. Wylie, C. C. Moeller, R. E. Holz, B. Maddux, B. A. Baum, K. I. Strabala,
and L. E. Gumley, 2008: MODIS Global Cloud-Top Pressure and Amount Estimation: Algorithm Description and Results.
J. Appl. Meteor. Climatol., 47, 1175-1198.
Platnick, S., M. D. King, S. A. Ackerman, W. P. Menzel, B. A. Baum, J. C. Riedi, and R. A. Frey, 2003:
The MODIS cloud products: Algorithms and examples from TERRA. IEEE Trans. Geosci. Remote Sens., 41, 459-473.