MODIS-derived NDVI Metrics
GINA and the National Park Service worked together to develop a MODIS-derived NDVI metrics algorithm. The data products from this project are available as a Web Coverage Service (WCS) with MODIS-derived yearly NDVI metrics. The data coverage includes the entire state of Alaska for the years between 2000 and 2016.
The NDVI metrics algorithm uses eMODIS data provided by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center. The data can be downloaded from the USGS-EROS eMODIS website.
NDVI Metrics WCS URL: http://ndvi.gina.alaska.edu/metrics?
The algorithm takes 7-day composite eMODIS NDVI data, performs data stacking, interpolating, smoothing, and then calculates the NDVI metrics. 12 metrics are produced by the algorithm:
- Onset of greenness /Start day of Season (SOS)
- NDVI value of onset of greenness
- End of greenness /End day of Season (EOS)
- NDVI value of end of greenness
- Duration of greenness – day range between onset of greenness and end of greenness
- Day with maximum NDVI
- Value of maximum NDVI
- Range of NDVI
- Rate of green up
- Rate of senescence
- Time-integrated NDVI
- Metrics ‘flag’, where -1=no data, 0=not valid data, 1=good data
The NDVI metrics algorithm technical document is available online.
The 12-band metrics files are accessible through the WCS server at URL: http://ndvi.gina.alaska.edu/metrics/emodis? The 5-band metrics files which includes band 1, 3, 5, 6, and 12 are also provided at WCS server URL: http://ndvi.gina.alaska.edu/metrics/emodis_5bands?
The 12-band NDVI metrics are also available through GINA’s http server at http://static.gina.alaska.edu/NPS_products/eMODIS_NDVI/eMODIS_derived_NDVI_metrics/version_1.0/
Sample Plots of the Metrics
Amy E. Miller, Chuck Lindsay, Parker Martyn from National Park Service Anchorage for developing NDVI metrics algorithm
David K. Swanson for evaluation and feedback of NDVI metrics algorithm Ecologist, Arctic Network National Park Service
Michael E Budde for evaluation and feedback of NDVI metrics algorithm Geographer – US Geological Survey Earth Resources Observation and Science (EROS) Center
Calli B. Jenkerson for providing and explanation of eMODIS products MODIS SS NASA LPDAAC USGS EROS ERT Contractor to the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center http://lpdaac.usgs.gov