fPar derived from MODIS for BA subregions

Abstract

This dataset was supplied to the Bioregional Assessment Programme by a third party and is presented here as originally supplied. Metadata was not provided and has been compiled by the Bioregional Assessment Programme based on the known details at the time of acquisition.

Fraction of photosynthetically active radiation derived from MODIS for BA. Used to generate a landcover maps for selected regions.

Files are CSV format and contain data (proportion) for fPAR_Total, fPAR_Persistent, fPAR_recurrent and P_BILO (rainfall_mm_month) for each month of the year for the period 2001-2012. Files for all subregions are present and named according to the following convention.

Filename = MODIS_fPAR_Monthly_BA_[region]_[subregion].csv

Donohue, R.J., McVicar, T.R. and Roderick, M.L. (2009) Climate-related changes in Australian vegetation cover as inferred from satellite observations for 1981-2006. Global Change Biology. 15(4), 1025-1039. doi:10.1111/j.1365-2486.2008.01746.x

Donohue, R.J., Roderick, M.L. and McVicar, T.R. (2008) Deriving consistent long-term vegetation information from AVHRR reflectance data using a cover-triangle-based framework. Remote Sensing of Environment. 112(6), 2938-2949. doi:10.1016/j.rse.2008.02.008

Purpose

Used to generate a landcover maps for selected regions.

Dataset History

Using time series NDVI imagery (ranges from -1 to +1, only negative for water bodies, with non-water surfaces ranging from near 0 for bare soil / no vegetation to near 1 for high vegetation amounts) from the MODIS sensor, specifically the MOD13Q1.005 product, which has a spatial resolution of 250m and is a composite of 16-days. The NDVI was scaled NDVI to total fPAR (fraction of Photosynthetic Active Radiation [i.e., 400nm to 700nm] absorbed by plants, which ranges from 0 to 1) using the approach of Donohue et al (2008). At each grid-cell the time series of total fPAR estimates are then temporally decomposed using the algorithm of Donohue et al (2009). This partitions the per-pixel and per time-step total fPAR estimate into the recurrent and persistent fPAR components. In general the recurrent component is related to crops / grasses with a strong annual cycle of greenness, and the persistent component is related to evergreen trees and shrubs. There are however vegetation types which do not accord to this "one-to-one" classification, for example evergreen / improved pastures (these are typically regarded as being persistent) and deciduous trees (these are typically regarded as being recurrent). The fPAR values (total, recurrent and persistent) where then converted to percentage green vegetation cover (ranging from 0% to 100%), this was performed assuming a 0.01 fPAR change represented a 1% change in vegetation cover. The digital numbers (DNs) of the fPAR data range between 0 to 1000, and so green percentage cover was calculated as fPAR value / 10. As examples, an fPAR DN of 500 = 50% and 350 = 35% etc.

Dataset Citation

CSIRO (2014) fPar derived from MODIS for BA subregions. Bioregional Assessment Source Dataset. Viewed 14 June 2018, http://data.bioregionalassessments.gov.au/dataset/299ec634-2919-4838-a163-a6804b95438c.