Ecosystem Disturbance Index

The Disturbance Index (DI; Mildrexler et al. 2007) combines estimates of LST and EVI to create an index that can be used to detect the timing, location and magnitude of major ecosystem disturbances. The DI can be used to detect disturbance such as wildfire, flooding, climate change and human-triggered changes in land use.

   The DI algorithm is based on the consistent radiometric relationship that exists between LST and EVI, computed on a pixel-by-pixel basis. The maximum values of LST and EVI can be related to major changes in surface energy partitioning and land cover respectively. Their ratio is used to detect major ecosystem disturbances. DI is computed as:

DI_LST/EVI = (LST_max / EVI_max) / (LST_mean/EVI_mean)

where:

DI_LST/EVI = Disturbance Index value.

LST_max = Annual maximum of 8-day LST composites.

EVI_max = Annual maximum of 16-day EVI composites.

LST_mean = Multi-year mean of LST_max.

EVI_mean = Multi-year mean of EVI_max.

REFERENCES

• Mildrexler, D. J., Zhao, M., Heinsch, F. A., and Running, S. W. (2007). “A New Satellite-Based Methodology for Continental-Scale Disturbance Detection”. Ecological Applications, 17(1)