Vegetation green leaf area index (LAI) and absorbed photosynthetically active radiation (fpar) are EOS standard data products as identified in NNH20ZDA001N-snppsp. The objective of this proposal is to…

This is a $581,114 grant awarded by the National Aeronautics and Space Administration (NASA) to the Trustees of Boston University to maintain and refine the algorithm for generating operational vegetation green leaf area index (LAI) and absorbed photosynthetically active radiation (FPAR) data products from the Suomi National Polar-orbiting Partnership (NPP) and Joint Polar Satellite System (JPSS) sensor series. The objective is to ensure continuity and consistency with the prior Moderate Resolution Imaging Spectroradiometer (MODIS) LAI/FPAR product time series. The work includes algorithm maintenance, product quality and uncertainty analysis, and research to detect long-term trends in LAI/FPAR and their impacts on the terrestrial carbon cycle. This grant supports NASA's Earth Science Division goals to provide consistent, sensor-independent global vegetation data for Earth system science and global change research.

Vegetation green leaf area index (LAI) and absorbed photosynthetically active radiation (fpar) are EOS standard data products as identified in NNH20ZDA001N-snppsp. The objective of this proposal is to maintain and minimally refine the algorithm for operational production of standard EOS global LAI/fpar products from suomi NPP viirs and jpss sensor series data and to comprehensively evaluate and validate these products to assure continuity with the EOS modis product time series. Prior work on viirs was focused on developing the algorithm and its implementation to generate collection 1 (C1) LAI/fpar products. The algorithm theoretical basis document (atbd) and user guide have been reviewed and adopted by the project office. Three peer refereed articles have been published on algorithm development, implementation, and evaluation of 5-years of C1 products. These efforts have documented robust and operational generation of LAI/fpar products from viirs sensor data and the potential for continuing the modis series of LAI/fpar products. Currently, the suomi/jpps project is planning C2 products to significantly enhance the C1 products. As part of this activity, we are proposing research geared towards operational generation of C2 LAI/fpar products from snpp (2012-2024) and JPSS1 (2018-2024) data that are consistent with the modis products. The proposed tasks are formulated along four broad fronts: (a) algorithm maintenance and sips implementation, (b) C2 product error and uncertainty analyses, (c) project activities and (d) scientific research with C2 products. The proposed work program is detailed in 12 specific tasks (1) analysis of C2 snpp and JPSS1 surface reflectances, (2) development of C2 snpp and JPSS1 look-up-tables, (3) science tests of new luts, (4) sips implementation, (5)-(9) assessing spatial coverage, continuity and consistency, product precision, accuracy and uncertainty and time series stability, (10) updating atbd and user guide, (11) operational quality assessment and project housekeeping activities and (12) community support and outreach activities. Proposed scientific research with the resulting C2 products include detecting long-term trends in LAI/fpar, their attribution to drivers and characterizing impacts to terrestrial carbon cycle and land surface temperature. The end-result of this activity is LAI/fpar products from snpp and jpss that are consistent (in terms of continuity, accuracy, precision, uncertainty and stability) with the long train of modis LAI/fpar products. These time series of products are sensor-blind and reflect the true spatio-temporal dynamics of vegetation on the ground, thus, suitable for research in earth system science, global change, and applied sciences a fundamental goal of NASA earth sciences division.