Ecosystem Disturbance Index - MODIS, Australia and New Zealand coverage (Experimental Product Version 1)

Ecosystem Disturbance Index - MODIS, Australia and New Zealand coverage (Experimental Product Version 1)

Figure 1:Disturbance Index image for 2009 over Australia and New Zealand

Link to the data

Data licence and Access rights

Abstract or Summary

The Disturbance Index (DI; Mildrexler et al. 2007) can be used to detect the timing, location and magnitude of major ecosystem disturbances such as wildfire, flooding, climate change and human-triggered land use. MODIS Aqua Land Surface Temperature (LST; MYD11A2) and Terra Enhanced Vegetation Index (EVI; MOD13A1) data from 2001 to 2013 were used to generate the DI product. The algorithm is based on the consistent radiometric relationship between LST and EVI computed on a pixel-by-pixel basis. Annual maximum composites of LST and EVI data were used to detect fundamental changes in land cover and surface energy partitioning.  Annual DI maps were calculated as,

    DI_LST⁄EVI =   LST_max / EVI_max

                      LST_mean / EVI_mean

where DI_LST⁄EVI is the disturbance index (DI) value, LST_max is the annual maximum of eight-day composite LST, EVI_max is annual maximum of 16-day EVI, LST_mean is the multiyear mean of LST_max and EVI_mean is multiyear mean of EVI_max.

Spatial and Temporal extents

Point of contact

Credit [optional]

Keywords

There are three main thesauri that AusCover recommends:

1. Global Change Master Directory (http://gcmd.nasa.gov)
2. Climate and Forecast (CF) convention standard names (http://cfconventions.org/standard-names.html).
3. Fields of Research codes (http://www.abs.gov.au/ausstats/abs@.nsf/0/6BB427AB9696C225CA2574180004463E?opendocument).

Data quality

LPDAAC are responsible for the actual data quality and provide quality channels as part of most products.  These channels are processed the same as the data channels.  The mosaicing, remapping and reformatting processes do not alter either the data or the quality fields.

Quality assessment of the LPDAAC MODIS products is undertaken by the MODIS Land Data Discipline Team, http://landweb.nascom.nasa.gov.

Data set specific link(s) for MOD13A1 and MYD11A2 products are:

• http://landweb.nascom.nasa.gov/cgi-bin/QA_WWW/getSummary.cgi?esdt=MOD11
• http://landweb.nascom.nasa.gov/cgi-bin/QA_WWW/getSummary.cgi?esdt=MYD11

Users should be aware that not all tiles for a particular mosaic necessarily become available from the LPDAAC on the same day.  It is therefore possible that the most recent mosaic for any given product will be updated over several days, each time containing progressively more actual data within the same (standard) geographic extent.

We have had some minor issues with file corruption that have been detected by users unable to un-gzip the mosaic files.  If you discover any such files, please report them to us (see contacts section).

Flags used for MOD13A1 datasets are as below:

Flags used for MYD11A2 datasets are as below:

Validation status

Quality assessment of the LPDAAC MODIS products is undertaken by the MODIS Land Data Discipline Team, http://landweb.nascom.nasa.gov.Data set specific link(s) for MOD13A1 and MYD11A2 products are:

• http://landweb.nascom.nasa.gov/cgi-bin/QA_WWW/getSummary.cgi?esdt=MOD11
• http://landweb.nascom.nasa.gov/cgi-bin/QA_WWW/getSummary.cgi?esdt=MYD11

Related products

References

Algorithm summary

Annual Disturbance Index (Mildrexler et al. 2007) maps were calculated as,    

   DI_LST⁄EVI =   LST_max / EVI_max

                      LST_mean / EVI_mean

where DI_LST⁄EVI is the disturbance index (DI) value, LST_max is the annual maximum of eight-day composite LST, EVI_max is annual maximum of 16-day EVI, LST_mean is the multiyear mean of LST_max and EVI_mean is multiyear mean of EVI_max.

Detailed user guide and ATBD can be found as the attachment dist_index_500m_aqua_ANZ_2009.pdf.

Product version history

Metadata history