Image 1: The first thermal images received from ASTER sensor on the Terra satellite of Ethiopia, 15 years ago. Thermal images like this are what Senay uses to monitor crop health in Ethiopia.
Gabriel Senay is a Research Physical Scientist with the US Geological Survey. He has developed a way to use thermal data from NASA's Terra and Aqua satellites, which record Earth's temperature for every square kilometer daily, along with historical temperature data from NOAA and the University of California at Berkeley.
In the past scientists have used a land's greenness to monitor the health of vegetation in an area. The problem with using greenness is that vegetation can stay green for weeks even after the crops have become stressed and begun dying.
Senay's technique uses thermal imaging to look at how plants "sweat" - evapotranspiration - to see how healthy they are. Evapotranspiration is a cooling process. When plants aren't releasing as much moisture, such as in the beginning of a drought, the land become hotter. These changes in temperatures can be seen almost immediately. Senay has found that these spikes in temperature are a reliable quick way to judge if an area is about to experiance a drought. Senay is focusing specifically on Ethiopia where there are rural farms and ranches which do not often have easy ways to communicate with agencies that could help during a drought. Senay hopes to take this monitoring a step further and create a mobile app where farmers can report their land changes as well as see weather forecasts. This app would also help connect experts, monitoring thermal data, to more quickly send aid to farmers before a drought, and famine, is in full swing.
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by Tess MacFarlane
