MODIS and VIIRS Land Surface Temperature and Emissivity: A Consistent and High Quality Continuity Data Record

Abstract:

A key Earth System Data Record (ESDR) identified by the NASA Earth Science Division is Land Surface Temperature and Emissivity (LST&E). LST&E data are key variables used in land cover/land use change studies, in surface energy balance and atmospheric water vapor retrieval schemes, and in climate research. LST&E products are currently produced by the MODIS instrument on NASA Earth Observing System (EOS) platform and by the VIIRS instrument on the Suomi-NPP platform, which serves as a bridge between NASA's EOS of satellites and the next-generation Joint Polar Satellite System (JPSS). The current split-window algorithm used to produce the VIIRS LST product deviates from its MODIS counterpart both in terms of its functional form and emissivity correction method, resulting in systematic discrepancies between the products based on the land cover type and atmospheric conditions. To address this issue we have developed a different algorithmic approach to ensure an acceptable and high quality continuity data record between MODIS and VIIRS LST&E. A new MODIS LST&E product (MOD21, C6) has been developed based on the well established Temperature Emissivity Separation (TES) algorithm, initially developed for ASTER. TES is a physical-based algorithm that simultaneously retrieves the LST and a dynamically varying multi-spectral emissivity. Using the same methodology, we are also in the process of developing an equivalent product for VIIRS that will produce LST and emissivity for VIIRS bands 14-16, equivalent to MODIS bands 29, 31, and 32. We will show progress on the VIIRS LST&E algorithm development and an initial trend analysis demonstrating continuity between MODIS and VIIRS LST&E products using the TES approach over the CONUS and dedicated validation targets covering a broad range of land and atmospheric conditions.