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Evaporative Stress Index

The following maps and data show where vegetation is stressed due to lack of water in Canada, averaged over the last four weeks. The information highlights where evapotranspiration or loss of water from the soil and plant canopies is higher than normal.

Map updated:

Legend: Description of this image follows.
Description – Legend

The map shows temporal anomalies in evapotranspiration (ET), highlighting areas under stress from Very high stress to Very low stress.

  • Red: Very high stress
  • Orange: High stress
  • Yellow: Average
  • Light green: Low stress
  • Dark green: Very low stress

Evaporative Stress Index (ESI) data

Download or view ESI maps and data from the NASA archive on the SERVIR Global website.

About satellite ESI maps

The ESI describes temporal anomalies in evapotranspiration (ET), highlighting areas with anomalously high or low rates of water use across the land surface. Here, ET is retrieved via energy balance using remotely sensed land-surface temperature (LST) time-change signals from the MODIS satellite. Land Surface Temperature changes quickly and the differences in cooling rates between well-watered canopies and those that are dry provides information on soil moisture and evapotranspiration  at relatively high spatial resolution. The ESI also demonstrates capability for capturing early signals of “flash drought,” brought on by extended periods of hot, dry and windy conditions leading to rapid soil moisture depletion.

Related link

For more information on the science behind this index: Mapping daily evapotranspiration at field to continental scales using geostationary and polar orbiting satellite imagery. Hydrology and Earth System Sciences, 15, 223-239 (2011). Anderson, M.C., Kustas, W.P., Norman, J.M., Hain, C.R., Mecikalski, J.R., Schultz, L., González-Dugo, M.P., Cammalleri, C., D'Urso, G., Pimstein, A., & Gao, F.

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