Sea-surface temperature measurements from the Moderate-Resolution Imaging Spectroradiometer (MODIS) on Aqua and Terra

The Terra and Aqua satellites are the flagships of the NASA Earth Observing System and carry suites of sensors designed to provide measurements of the climate system suitable for many research applications. Each satellite carries a Moderate-Resolution Imaging Spectroradiometer (MODIS), which are very complex imaging radiometers operating in both the visible and infrared parts of the electromagnetic spectrum. One of the primary variables that is derived from some of the infrared measurements of MODIS is sea-surface temperature (SST). There are two spectral intervals located where the atmosphere is relatively transparent, at about 4 and 11 micrometer wavelengths, where SST measurements can be made in cloud-free conditions, although the contamination of the shorter wavelength measurements by reflected sunlight limits these to the night-time part of each orbit. The atmospheric correction algorithms used to derive SSTs are described, along with radiometric and sub-surface measurements used to determine the error characteristics of the retrieved fields