Issue concerning VI Phenology Products:
- MOD09A1P_NDVI 500m gap-filled NDVI Phenology
- MOD09A1Q_NDVI 250m gap-filled NDVI Phenology
- MOD09A1P_EVI 500m gap-filled EVI Phenology
- MOD09A1Q_EVI 250m gap-filled EVI Phenology
PLEASE NOTE: We found an issue with how snow-covered pixels are handled
in all MODIS-for-NACP VI Phenology products at latitudes higher than 37.5 N.
The problem is that the appearance and disappearance of snow are identified
as plant phenology. Therefore, earlier greenup dates and later
browndown dates are reported. The detected growing season is reported as
longer than the actual growing season.