Data / Science Data Products / VAPs

SPHOTCOD

Cloud optical depth retrieved from multi-channel sunphotometer

Baseline VAP

This value-added product (VAP) retrieves cloud properties from three-channel sunphotometer data at wavelengths of 440, 870, and 1640 nanometers following published methods of Chiu et al. (2012) and Sookdar et al. (2025).

For its inputs, the VAP uses zenith radiance measurements at the three wavelengths from the AErosol RObotic NETwork (AERONET), solar constant values, and surface albedo data from the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS).

The VAP outputs are cloud droplet effective radius, cloud optical depth, and/or liquid water path. The VAP produces a daily file in netCDF format.

Scientists can use the data for studies of cloud processes, cloud-aerosol interactions, and cloud radiative impacts.