Product User GuidePI - Ranga Myneni (Boston University)
Product ATBD Co-I: Yuri Knyazikhin (Boston University)

Global LAI/FPAR Earth System Data Records from NPP-VIIRS to Extend the EOS-MODIS Time Series

The justification for continuing the EOS MODIS LAI/FPAR data series with NPP-VIIRS and NPOESS measurements may be succinctly summarized as follows: (1) these products have a large user base, (2) the algorithm is mature and proven to generate accurate products, (3) the products can be generated with minimal investment from VIIRS data, and (4) the resulting continuous, well-characterized, long time series will help us to address the many critical Earth system science, global change, and/or applied sciences questions, thus meeting the primary goal of the NPP/NPOESS missions. Thus the goal is to produce a continuous, well-characterized, long time series of global LAI and FPAR products, spanning the EOS and NPP era, that are suitable for research in Earth system science, global change and applied sciences.

The VIIRS Look-Up-Tables (LUTs) are developed by adjusting certain parameters of the stochastic radiative transfer model such that the modeled reflectances match the measured reflectances and at the same time the retrieved LAI distributions are similar to a pre-set standard (e.g. Aqua MODIS or a large set of measurements; bottom panels).

That is why it is important to have simultaneous measurements from two sensors (e.g. MODIS and VIIRS) in order to ensure continuity of the data record.

Comparison of MODIS and VIIRS LAI/FPAR

lai/fpar VIIRS/MODIS

Both products show distinct annual seasonality of each biome, VIIRS LAI product tend to be higher than MODIS LAI


LAI viirs/modis comparison

Comparison of LAI & FPAR for Aqua MODIS and Suomi VIIRS (August & September 2012)

MODIS-like LAI/FPAR products are being produced from Suomi VIIRS data at the Land SIPS using MODIS (C6) code with adjustments for VIIRS sensor. Comprehensive and exhaustive testing of C6 MODIS LAI/FPAR (Terra/Aqua) and Suomi VIIRS LAI/FPAR is required, using at least 2 overlapping years of data.

The products are provided in standard Hierarchical Data Format–Earth Observing System (HDF-EOS5) format. Currently, this collection is available from January 19, 2012 and forward.  Products from the VIIRS sensor aboard JPSS-1 (J1) will be also be available starting in mid-2023.

Product Details and DAAC links

Product Name SNPP JPSS-1
Leaf Area Index/FPAR 8-Day L4 Global 500 m SIN Grid VNP15A2H VJ115A2H