VIIRS/SNPP Cloud Properties COSP Level 3 daily, 1x1 degree grid

Notably, this CLDPROPCOSP product is analogous to products generated in parallel for the Moderate Imaging Spectroradiometer (MODIS)/Aqua and VIIRS/NOAA-20 missions. MODIS and VIIRS cloud and aerosol observations provide important data to help us better understand climate model performance. For example, observations of cloud-aerosol interactions could prove useful to diagnose errors in climate models.

The COSP MODIS simulator did not map well to the standard MODIS L3 monthly products. Therefore, this motivated the development of a parallel L3 product better tailored for comparisons with the CFMIP MODIS simulator. The VIIRS/SNPP CLDPROPCOSP L3 products are comparable to the companion Aqua MODIS CLDPROPCOSP L3 products, though both may have differences with respect to the CFMIP MODIS simulator output and the MCD06_COSP L3 products given the key CLDPROP L2 algorithm and forward-model changes with respect to MOD06/MYD06 described in Platnick et al., (2021)¹.

CLDPROPCOSP_D3_VIIRS_SNPP represents the short-name of the daily product in netCDF4 format. It provides a set of 32 aggregated science datasets (SDS) with specific definitions for better comparison with climate model output. They include the following: 1.

Cloud Mask Fraction 2. Cloud Mask Fraction Low 3. Cloud Mask Fraction Mid 4.

Cloud Mask Fraction High 5. Cloud Optical Thickness Ice 6. Cloud Optical Thickness Liquid 7.

Cloud Optical Thickness Total 8. Cloud Optical Thickness PCL Ice 9. Cloud Optical Thickness PCL Liquid 10.

Cloud Optical Thickness PCL Total 11. Cloud Optical Thickness Log10 Ice 12. Cloud Optical Thickness Log10 Liquid 13.

Cloud Optical Thickness Log10 Total 14. Cloud Particle Size Ice 15. Cloud Particle Size Liquid 16.

Cloud Particle Size PCL Ice 17. Cloud Particle Size PCL Liquid 18. Cloud Retrieval Fraction Ice 19.

Cloud Retrieval Fraction Liquid 20. Cloud Retrieval Fraction Total 21. Cloud Retrieval Fraction PCL Ice 22.

Cloud Retrieval Fraction PCL Liquid 23. Cloud Retrieval Fraction PCL Total 24. Cloud Top Pressure 25.

Cloud Water Path Ice 26. Cloud Water Path Liquid 27. Cloud Water Path PCL Ice 28.

Cloud Water Path PCL Liquid 29. Sensor Azimuth 30. Sensor Zenith 31.

Solar Azimuth 32. Solar Zenith Each science parameter includes a combination of the following statistical variables:

• Mean, Pixel Count, Standard Deviation, Sum, and Sum Squares
• Joint histogram versus Cloud Particle Size
• Joint histogram versus Cloud Optical Thickness
• Joint histogram versus Cloud Top Pressure
• Joint histogram versus Cloud Water Path Consult the CLDPROPCOSP User Guide (v3.0) for details, including how the L3 daily statistics are computed and to learn more about the gridding and sampling protocols specific to this product. Each calendar year includes 365 granules. The version 1.1 collection of this product starts from July 4, 2002 (Day-of-year 185) and currently is produced through the present. Additional PI-suggested resources:
• Data description paper + links to Model code/software, etc.
• GitHub repository that contains Python scripts for manipulating the monthly MODIS datasets to support the MODIS simulator for climate models --- ¹ Platnick, S., Meyer, K., Wind, G., Holz, R., Amarasinghe, N., Hubanks, P. A., Marchant, B., Dutcher, S., and Veglio, P.: The NASA MODIS-VIIRS continuity cloud optical properties products, Remote Sensing, 13, https://doi.org/10.3390/rs13010002, 2021.