fPar derived from MODIS for the Sydney Basin

Abstract

The dataset was derived by the Bioregional Assessment Programme. This dataset was derived from the fPar derived from MODIS for BA subregions dataset. You can find a link to the parent dataset in the Lineage Field in this metadata statement. The History Field in this metadata statement describes how this dataset was derived.

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

File geodatabase contains the following rasters

lta_persistent_SYD: long term annual average persistent veg cover

lta_ recurrent_SYD: long term annual average recurrent veg cover.

lta_total_SYD: long term annual average total cover (ie the sum of persistent + recurrent)

12 grids

ltm_recurrent_xx_SYD: long term monthly average recurrent veg cover. xx = 01, 02..12 ie month.

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

Dataset History

Using time series (Normalised Differential Vegetation Index (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

Bioregional Assessment Programme (2014) fPar derived from MODIS for the Sydney Basin. Bioregional Assessment Derived Dataset. Viewed 07 February 2017, http://data.bioregionalassessments.gov.au/dataset/5d80eb34-895c-4fba-a582-7a6380d55d40.

Dataset Ancestors

• Derived From fPar derived from MODIS for BA subregions