RSPM/eMODIS
RSPM(Remotely Sensed Phenology Measurements) provides annual vegetation phenology metrics from two data sources eMODIS & eVIIRS. eMODIS originally collected data at 250 m resolution from 2001 to 2020, while eVIIRS (375 m resolution) succeeded eMODIS from 2021 to present. To simplify data access, we chose to resample eMODIS to the 375 m resolution and only processed data 2016-present.
DEVISE summarizes the following RSPM variables over user selected temporal and spatial options. All variables are derived from a combination of eMODIS and eVIIRS satellites, and are measured using NDVI (Time Integrated ‘tin’ Normalized Difference Vegetation Index; more details here).
- Daily & monthly temporal intervals are unavailable for these variables.
Day of Max Photosynthesis (maxt)
This variable represents the day of year in which maximum photosynthetic activity occurred.
- Annual data describes the day of maximum photosynthetic activity
Days of Photosynthetic Activity (Duration, dur)
This variable represents the number of days photosynthetic activity and describes the length of the growing season.
- Annual data describes the length of the growing season in days
End Day of Photosynthesis (eost)
This variable represents the day of year in which photosynthetic activity no longer occurred.
- Annual data describes the last day of photosynthetic activity
Start Day of Photosynthesis (sost)
This variable represents the day of year in which photosynthetic activity began.
- Annual data describes the day of year where measurable photosynthetic activity began
Time Integrated NDVI (tin)
This variable represents the NDVI (Normalized Difference Vegetation Index) above the baseline for the entire duration of the growing season and is a measurement of canopy photosynthetic activity.
- Annual data describes the canopy’s photosynthetic activity across the entire growing season (interpolated NDVI)