COSMOS project

A team of researchers led by Marek Zreda in coordination with Jim Shuttleworth and Xubin Zeng was recently funded to build a network of soil moisture probes for meteorological measurement across the United States. The project has previously been featured by the UA News service here. As with all NSF funded projects the investigators project summary can be viewed by the public. The project relies on deploying a set of probes that count neutrons using a portable detector. The concept is similar to the classic neutron probe but instead of using a live neutron source the device counts neutrons that are excited by natural cosmic rays similar to classic neutron probe methods the presence of water slows down these naturally occurring neutrons and thus the fewer neutrons counted the greater the water content (Zreda et al 2008). A key attribute of the probes is the relatively large area that affects the neutrons that are counted. The observational footprint of the device has a radius of 330 m and is most sensitive to soil moisture near the surface (up to a depth of 50 cm). This footprint and depth profile makes the device ideal for soil moisture observations in and around meteorological stations. this application was one of the keys to getting the project funded by NSF. The field deployment of these devices promises to revolutionize our understanding of the role that soil moisture plays in land surface atmosphere feedbacks.