Washington: NASA is developing a new space-based instrument to monitor plant health that will study how plants react to heat and water stress and identify drought-resilient plants. The instrument, called the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS), will monitor one of the most basic processes in living plants: the loss of water through the tiny pores in leaves. When people lose water through their pores, the process is called sweating.
The related process in plants is known as transpiration. Because water that evaporates from soil around plants also affects the amount of water that plants can use, ECOSTRESS will measure combined evaporation and transpiration, known as evapotranspiration. "If plants do not get enough water, they show signs of stress. By measuring evapotranspiration, we get an early indicator of that stress, and we can do something about it before the plants collapse," said Simon Hook, a scientist at Jet Propulsion Laboratory, Pasadena, California, and the project's principal investigator.
ECOSTRESS's science instrument is a high-resolution thermal infrared radiometer, which works like a giant thermometer from space to measure the temperature of plants and the amount of heat radiating from Earth's surface. "If we find a plant is too hot, that's because it's not getting enough water to cool itself down," said Josh Fisher, a JPL research scientist and science lead for ECOSTRESS. "That has huge implications for our understanding of global water and carbon cycling, and which plants are going to live or die in a future world of greater droughts," Fisher said. ECOSTRESS will provide a four-day repeat cycle and a spatial resolution of 125 feet by 185 feet, high enough to see most farms and small differences within ecosystems. "We are keeping an eye on how ECOSTRESS can be applied not only to science but society at large," said Andy French, a US Department of Agriculture scientist and member of the mission's team. "It could be very useful for water managers and farmers," said French.
By combining the instrument's measurements with other ecosystem data, scientists will be able to calculate how efficiently plants use water to process carbon dioxide and identify plants likely to be more resilient during droughts. The mission will target regions where models disagree about water use efficiency, and ECOSTRESS data will be used to improve those models. Scheduled for completion in 2017 and launch between 2017 and 2019, ECOSTRESS is one of two instruments selected for NASA's Earth Venture-Instrument series of missions.
