MODIS EVI time series analysis

Knowledge graph centered on MODIS EVI time series analysis with 74 nodes and 173 connections. Top connected: phenological mismatch, climate change, Populus, Populus tremuloides, snowpack persistence.

Method synopsis

Harmonized Landsat 8 and Sentinel-2 imagery processed through continental-scale algorithms to create vegetation index time series and estimate phenophase transition timing at 30 m resolution.

Synthesized from method descriptions across 3 papers using this protocol.

Procedure from a recent peer-reviewed implementation

Steps below were extracted from the most recent peer-reviewed implementation of this protocol in the corpus — Climate lags and genetics determine phenology in quaking aspen (Populus tremuloides) (2023), New Phytologist. Implementations in other papers (listed below) may differ.

1. Phenology data extraction
   Phenology estimates were obtained using a continental-scale land surface phenology algorithm and data product based on harmonized Landsat 8 and Sentinel-2 imagery. Algorithm creates a time series of vegetation indices from satellite imagery, which are then used to estimate the timing of vegetation phenophase transitions at 30 m spatial resolution. Assigned greenup date as the day of year on which 15% maximum greenness was reached, greendown date as the day of year on which 85% of maximum greenness decrease was reached, growing season length as the difference between the 50% greenup and greendown dates, maximum greenness as the maximum value of EVI2 (Enhanced Vegetation Index, dimensionless from 0 to 1).
   Quantities: 30 m spatial resolution phenology estimates for 2016-2019Duration: Processed for years 2016-2019Conditions: Continental-scale algorithm processing
   Equipment: Landsat 8 imagery, Sentinel-2 imagery, continental-scale phenology algorithm, EVI2 calculations

Typical Equipment

• Landsat 8 imagery
• Sentinel-2 imagery
• continental-scale phenology algorithm
• EVI2 calculations

Output Measurements

• greenup date
• greendown date
• growing season length
• maximum greenness

Papers Using This Protocol (4)

Species Studied With This Protocol

Places Where Used