An Overview of the MODIS Collection 7 Cloud Products

The NASA MODIS Science Team cloud products provide well characterized, global, multi-decadal data records of cloud occurrence (masking) and cloud-top and optical/microphysical (thermodynamic phase, optical thickness, effective radius, water path) properties from the Terra and Aqua satellites. The MODIS standard cloud mask products (NASA Earth Science Data Set filename identification MOD35 and MYD35 for MODIS Terra and Aqua, respectively) and cloud-top/optical products (MOD06 and MYD06, respectively) are in Collection 6.1 forward processing, with reprocessing having completed in 2017 (Terra) and 2018 (Aqua). The team is currently working on finalizing the development and testing of Collection 7 (C7) algorithms, with reprocessing expected to start in the first half of 2025.

In addition to improved sensor calibration, updates for C7 involve major science enhancements to the cloud products, including new SW and LW broadband TOA and surface flux calculations enabling radiative studies consistent with the cloud-top/optical property retrievals and a new cloud thermodynamic phase classification algorithm leveraging machine learning, among others. In this presentation, we provide an overview of C7 updates along with a retrospective of the advances made over previous Collections.

Throughout the 24 and 22 years of MODIS Terra and Aqua, respectively, science operations, the cloud products have been widely used for climate and process studies. With two-decade plus data record from the sensors, these cloud datasets are now becoming useful for climate analysis only because close attention has been given to characterizing and correcting radiometric calibration as well as consistency in the use of radiative transfer and ancillary datasets. A critical challenge is in bridging cloud data records across the EOS MODIS and Suomi NPP/JPSS VIIRS era given the substantial spectral channel differences between the sensors and other instrument characteristics; this continuity work (CLDPROP) being done by member of the same team will be discussed in a separate abstract.