MODIS Sea Surface Temperature
Overview
NASA standard processing and distribution of the Sea Surface Temperature (SST) products from the MODIS sensors is now performed using software developed by the Ocean Biology Processing Group (OBPG). The OBPG generates Level-2 SST products using the Multi-Sensor Level-1 to Level-2 software (l2gen), which is the same software used to generate MODIS ocean color products. The SST algorithm and quality assessment logic are the responsibility of the MODIS Science Team Leads for SST (currently P. Minnett and R. Evans of the Rosenstiel School of Marine and Atmospheric Science (RSMAS) at the University of Miami). Details of the SST processing implementation within l2gen are provided in this document. The description is valid for both the standard products distributed by the OBPG through the ocean color web and the products delivered to the Physical Oceanography DAAC, where the latter are subsequently repackaged for GHRSST distribution.
An historical discussion on the transition of SST processing from MODAPS/DAAC/RSMAS to OBPG, with comparison of products, is available here. At the time of transition, the OBPG was able to demonstrate exact consistency with the previous products. However, file formatting now follows OBPG conventions.
The Short-wave SST Algorithm makes use of MODIS bands 22 and 23 at 3.959 and 4.050 um. The brightness temperatures are derived from the observed radiances by inversion (in log space) of the radiance versus blackbody temperature relationship. For l2gen, these relationships were precomputed for the spectral response of each MODIS channel, and the tables were then stored in HDF files to be loaded at run-time. In modsst, the radiance versus blackbody temperature relationship was computed at run-time. The algorithm for computing short-wave SST (sst4) from observed brightness temperatures is shown below.
The long-wave SST algorithm makes use of MODIS bands 31 and 32 at 11 amd 12 um. The brightness temperatures are derived from the observed radiances by inversion (in linear space) of the radiance versus blackbody temperature relationship. For l2gen, these relationships were precomputed for the spectral response of each MODIS channel, and the tables were then stored in HDF files to be loaded at run-time. In modsst, the radiance versus blackbody temperature relationship was computed at run-time. The nonlinear SST algorithm was tuned for two different regimes based on brightness temperature difference. The algorithm for computing long-wave SST (sst) from observed brightness temperatures is shown below. Support for the VIIRS mission is currently work in progress.
Product Information
• Validated Stage: Stage 3
• ATBD
• DOI:
Terra
NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): MODIS-Terra Ocean Color Data; NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group. http://dx.doi.org/10.5067/TERRA/MODIS_OC.2014.0
Accessed on 07/28/2015.
Aqua
NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): MODIS-Aqua Ocean Color Data; NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group. http://dx.doi.org/10.5067/AQUA/MODIS_OC.2014.0
Accessed on 07/28/2015.
Product Details
All of the MODIS Sea Surface Temperature Data Products can be found at the PODAAC Website.
