Fractional Cover - MODIS, CSIRO algorithm 

Vegetation Fractional Cover represents the exposed proportion of Photosynthetic Vegetation (PV), Non-Photosynthetic Vegetation (NPV) and Bare Soil (BS) within each pixel. The sum of the three fractions is 100% (+/- 3%) and shown in Red/Green/Blue colors. In forested canopies the photosynthetic or non-photosynthetic portions of trees may obscure those of the grass layer and/or bare soil. This product is derived from the MODIS Nadir BRDF-Adjusted Reflectance product (MCD43A4) collection 6 and has 500 meters spatial resolution. A suite of derivative products are also produced including monthly fractional cover, total vegetation cover (PV+NPV), and anomaly of total cover against the time series. Monthly: The monthly product is aggregated from the 8-day composites using the medoid method. Anomaly: represents the difference between total vegetation cover (PV+NPV) in a given month and the mean total vegetation cover for that month in all years available, expressed in units of cover. For example, if the mean vegetation cover in January (2001-current year) was 40% and the vegetation cover for the pixel in January 2018 was 30%, the anomaly for the pixel in Jan 2018 would be -10%. Decile: represents the ranking (in ten value intervals) for the total vegetation cover in a given month in relation to the vegetation cover in that month for all years in the time-series. MODIS fractional cover has been validated for Australia. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. Funding was provided by CSIRO (Australia), Terrestrial Ecosystem Research Network (TERN) (Australia), and the Australian Government Department of Agriculture. 

This project will bring the enhancements to the ground cover monitoring tool (the RaPP Map) needed to assist in enabling the NRM agencies and individuals to undertake monthly reporting on ground cover level change. Proposed enhancements include: Continuity of the tool data quality increase the number of outputs required by NRMs improve the functionality as determined by the users This project is closely aligned with the Ground cover training and target setting (GTTS) project being proposed by John Leys from the NSW OEH which focuses on the training in the use of the tool to NRM agencies. This project is also contributing to the international engagement via the GEOGLAM initiative which aims at improving the information on agricultural productivity. 

Monthly vegetation cover is calculated from the 8-day composites using a medoid method as described in Gill et al. Monthly anomalies show the difference between total vegetation cover (PV+NPV) in a given month and the mean total vegetation cover for that month in all years available\nMonthly deciles show the decile (ranking) for the total vegetation cover in a given month in relation to the vegetation cover in that month for all years in the time series. Version 3.0: Fractional cover was derived using a linear unmixing methodology (Guerschman et al. 2015). Version 3.1: ("v310") Same as Version 3.0 with the following modifications: 1- input data changed to MODIS Collection 6.0 (MCD43A4.006) (see source). 2- calibration dataset expanded to include ~3022 field measurement sites accross Australia. 3- overall accuracy improved to an RMSE of 11.3%, 16.1% and 14.7% for the PV, NPV and BS fractions respectively.