Samuel C. Zipper
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high resolution mapping of evapotraspiration (HRMET)

HRMET Code + Manual now on GitHub: https://github.com/szipper/HRMET

One challenge for precision agriculture is quantifying spatial variability in plant water use, or evapotranspiration, at high (~1 m) spatial resolutions. To address this challenge, I developed the surface energy balance model High Resolution Mapping of Evapotranspiration (HRMET), described in a 2014 publication (link) (pdf). HRMET is designed to take very few inputs (meteorological data, canopy surface temperature, and a vegetation index) and calculate instantaneous evapotranspiration (ET) rates, without the requirement of 'dry' and 'wet' pixels characteristic of many remotely sensed techniques. ​This advance allows HRMET to be used during both open- and closed-canopy conditions with homogeneous cover, e.g. agroecosystems.

Key Publications
​
Zipper SC & SP Loheide II (2014). Using evapotranspiration to assess drought sensitivity on a subfield scale with HRMET, a high resolution energy balance model. Agricultural & Forest Meteorology, 197: 91-102. DOI: 10.1016/j.agrformet.2014.06.009 (link) (pdf)
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By comparing normalized ET rates across dry & wet image collection dates, HRMET can be used as a non-destructive tool to map drought sensitivity at meter-scale within agricultural fields:

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I am working with collaborators to test HRMET in other crop types (potatoes & beans) in the Central Sands region of Wisconsin to better understand how cropping decisions impact the water balance in a region with baseflow-dominated streams and many groundwater-dependent ecosystems.

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  • Home
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    • GitHub
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