Earth  ID: 30385

Monthly Cloud Optical Thickness (Terra/MODIS)

To better understand the role of clouds in the Earth's climate system, scientists need two important measurements: cloud optical thickness and cloud particle size. A cloud's optical thickness is a measure of attenuation of the light passing through the atmosphere due to the scattering and absorption by cloud droplets. Clouds do not absorb visible wavelengths of sunlight; rather, clouds scatter and reflect most visible light. The higher a cloud's optical thickness, the more sunlight the cloud is scattering and reflecting. These maps show monthly cloud optical thickness from January 2005 to the present, produced using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard NASA’s Terra satellite. Dark blue shades indicate areas where there are low cloud-optical-thickness values, while white shades indicate high values (i.e., greater attenuation caused by the scattering and absorption from cloud droplets).

For More Information


Marit Jentoft-Nilsen: Visualizer
Reto Stockli (NASA/GSFC): Visualizer
Based on imagery by Reto Stockli, NASA's Earth Observatory, using data provided by the MODIS Atmosphere Science Team, NASA Goddard Space Flight Center.

Short URL to share this page:


Data Used:
Note: While we identify the data sets used in these visualizations, we do not store any further details nor the data sets themselves on our site.

This item is part of this series:
NASA Earth Observations

DLESE >> Atmospheric science
GCMD >> Earth Science >> Atmosphere >> Clouds >> Cloud Optical Depth/Thickness
SVS >> Hyperwall
NASA Science >> Earth
SVS >> Presentation

GCMD keywords can be found on the Internet with the following citation: Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version