Growing Season Metrics for Alaska Derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) Satellite Normalized Difference Vegetation Index (NDVI) 2003-2021

The National Park Service and Geographic Information Network of Alaska (GINA) developed an algorithm to derive annual growing season metrics for Alaska using Moderate Resolution Imaging Spectroradiometer (MODIS) data, specifically eMODIS data provided by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center (https://doi.org/10.5066/F7H41PNT). The data products from this project are available as 250-meter-resolution raster images of MODIS-derived yearly Normalized Difference Vegetation Index (NDVI) metrics. The data coverage for growing season metrics derived from eMODIS version 6 includes the entire state of Alaska for the years between 2003 and 2021, and metrics derived from eMODIS version 5 include years 2000-2016. Currently version 6 are available for download. The algorithm takes 7-day composite eMODIS NDVI data, performs data stacking, interpolating, smoothing, and then calculates the NDVI metrics. The yearly NDVI metrics data include 12 metrics: day of onset of greenness (onp), NDVI value at onset day (onv), day of end of greenness (endp), NDVI value at the end day of greenness (endv), the duration of greenness season (durp), the day of the maximum NDVI value (maxp), maximum NDVI value (maxv), range of NDVI values (ranv), rate of green up (rtup), rate of senescence (rtdn), time-integrated NDVI (tindvi), NDVI metrics flag (mflg) where -1=no data, 0=not valid data, 1=good data