Earthdata Forum

Help: Cloud parameter problem in CERES single footprint data
In CERES 'satellite product SSF, different bands of cloud droplet water particle radius and ice water particle radius (3 different bands of 1.2, 2.1 and 3.7 microns) are provided, but the liquid water path and ice water path are 3.7 microns. Cloud visible optical thickness; Logarithmic visible optical thickness is also in 3 different bands (0.65, 1.2, 2.1 microns), I need to get the actual cloud optical thickness value information, liquid water particle radius, ice water particle radius. How should I choose and calculate to get the radiation information with the actual cloud? Corresponding to the correct cloud optical thickness and cloud droplet particle radius information values (PS: because I see the optical thickness for the cloud is 0.65 micron channel; For cloud droplet particle radius is 3.7 micron channel).
I need to get the optical thickness of the actual cloud and the cloud droplet particle radius information, how to calculate it, if possible, can you give me some reference materials? Sincerely thank you for your help and hope to get your reply in time.

The 0.65 optical depth and the 3.7 particle radius and water path are consistent. These are the values generally used in radiative transfer model calculation.

Looking at clouds at different wavelengths provide additional information about the cloud properties and are useful in doing spectral band radiative transfer.

All three values of optical depth or particle radius are obtained from observing the cloud just in different wavelength bands.

The optical depth, particle radius, and water path are related which is why for the 1.2 and 2.1 micron values only the optical depth and radius values are provided. The references below provide information on calculating water path.

I would add the following references to the earlier reply:

The references for cloud information on the SSF are

The Data Quality Summary
https://ceres.larc.nasa.gov/documents/DQ_summaries/CER_SSF_Terra-Aqua_Edition4A.pdf

and cloud portion
https://ceres.larc.nasa.gov/documents/DQ_summaries/ssf_cloud_prop_terra-aqua_Ed4A.pdf

Papers about the algorithms

Minnis, P., S. Sun-Mack, Y. Chen, F. Chang, C. R. Yost, W. L. Smith, P. W. Heck, R. F. Arduini, S. T. Bedka, Y. Yi, G. Hong, Z. Jin, D. Painemal, R. Palikonda, B. R. Scarino, D. A. Spangenberg, R. A. Smith, Q. Z. Trepte, P. Yang, Y. Xie, 2020: CERES MODIS Cloud Product Retrievals for Edition 4–Part I: Algorithm Changes. IEEE Transactions on Geoscience and Remote Sensing, 1-37. doi: 10.1109/TGRS.2020.3008866

Minnis, P., S. Sun-Mack, D. Young, P. Heck, D. Garber, Y. Chen, D. Spangenberg, R. Arduini, Q. Trepte, W. Smith, J. Ayers, S. Gibson, W. Miller, G. Hong, V. Chakrapani, Y. Takano, K. Liou, Y. Xie, P. Yang, 2011: CERES Edition-2 Cloud Property Retrievals Using TRMM VIRS and Terra and Aqua MODIS Data #x2014;Part I: Algorithms. IEEE Transactions on Geoscience and Remote Sensing, 49(11), 4374-4400. doi: 10.1109/TGRS.2011.2144601