New soil moisture sensor tracks drought conditions in Arizona, Mexico


June 26, 2014

Soil moisture measurements are needed to improve our understanding of water availability in rural and urban areas. Adam Schreiner-McGraw, an Arizona State University graduate student studying hydrology, has installed a new type of soil moisture sensor in four different ecosystems in the southwestern U.S. and northwest Mexico. Currently in the second year of measurements, these probes have tracked remarkably well the moderate drought conditions in Arizona and the aid provided by the wetter-than-average conditions during last summer’s monsoon.

Many parts of the hydrologic cycle are difficult to measure (such as groundwater movement or evapotranspiration), so mathematical models are used to help estimate these fluxes and understand how the hydrologic cycle might be changing. Schreiner-McGraw hopes that the data obtained by these soil moisture sensors can be used to improve watershed hydrology models used commonly for assessing impacts of land cover or climate change. Maryvale COSMOS sensor Download Full Image

About the size of a person and shaped like a space shuttle, these novel probes are called cosmic-ray soil moisture sensors. They are affiliated with the COSMOS (cosmic-ray soil moisture observing system) project, a National Science Foundation-supported project to measure soil moisture based upon cosmic-ray neutrons. An off-the-shelf device, these solar-powered sensors have remote data capture and can be installed in two days with a single field calibration.

The technology uses "fast neutrons" generated when cosmic-rays hit the atmosphere, cascade onto the land surface and are captured by hydrogen atoms. Intermediate scale measurements are possible, meaning that soil moisture is averaged over several hundred square meters. This allows observations that are in between traditional soil sensors and satellite estimates, the two most common ways to measure soil moisture. The sensor itself measures the density of fast neutrons above the soil surface. This density is inversely proportional to the amount of hydrogen bound in water within and above the soil surface. The higher number of neutrons measured by the sensor, the drier the soil is, providing a means to track water availability in rural or urban areas.

“We are currently obtaining real-time soil moisture data at three rural sites – southern Arizona, southern New Mexico and Sonora, Mexico – that have each been affected by human-induced land cover change,” explains Schreiner-McGraw, who is pursuing a doctorate in ecohydrology within the School of Earth and Space Exploration under the supervision of ASU associate professor Enrique R. Vivoni.

The two rural sites in the United States are undergoing woody plant encroachment, a process in which woody shrubs have occupied historical desert grasslands, while the site in Mexico had woody trees cleared away for the establishment of a pasture for cattle grazing. Both of these land cover changes are widespread throughout the world in arid and semiarid regions. Schreiner-McGraw is investigating the effects of these land cover changes on the water cycle, and the implications on ecosystem functioning, runoff generation and soil erosion.

“Recently, I installed another sensor in west Phoenix within the Maryvale community. To my knowledge, this is the first time one of these sensors has been installed in an urban setting. It is difficult to obtain an accurate measurement for soil moisture in urban settings because these sensors measure all sources of water in the footprint, so if somebody fills up their bathtub, it will likely affect the measurement,” says Schreiner-McGraw. “What we have found so far is that the neutron count rate in an urban setting is much lower and more stable than in the various rural areas that we are sampling. This indicates that soil moisture is likely higher and less variable in our urban setting, probably due to the large amount of urban irrigation occurring in Phoenix.”

According to Schreiner-McGraw, these sensors are useful because they provide a single value for soil moisture over a large region that is being sampled, thus averaging the amount of water available at scales relevant for management purposes. A network of such sensors in a metropolitan area, such as Phoenix, could aid in quantifying outdoor water use at an intermediate scale, a highly elusive measurement due to the large variations among individual homeowners.

“Hopefully, integrating this type of soil moisture data into hydrologic models of rural and urban areas will improve our ability to predict the changing hydrologic cycle,” says Schreiner-McGraw, who after graduation would like to continue doing research, perhaps with the U.S. Geological Survey, the U.S. Department of Agriculture or at a university as a professor.

Nikki Cassis

marketing and communications director, School of Earth and Space Exploration

Arizona PBS moves to ASU Cronkite School


June 26, 2014

Media organization to serve as hub for news innovation

Eight, Arizona PBS, the 53-year-old public television station based at Arizona State University with more than 1 million viewers, will become part of ASU's Walter Cronkite School of Journalism and Mass Communication, continuing to provide quality PBS programming while serving as a national hub for news innovation and reinvention, the university announced June 26. ASU Cronkite School Download Full Image

Eight, which includes three TV channels and azpbs.org, will be the largest media organization operated by a journalism school in the world when the move becomes official next Tuesday. The station had been part of ASU’s Office of Public Affairs.

“Eight has served Arizonans for more than 50 years, providing important national and regional content in public affairs, education, the arts, science and culture across our state,” said ASU President Michael M. Crow. “That critical mission will continue and we will redouble our efforts to make Arizona PBS the best public television enterprise in the nation featuring all of the outstanding PBS programming now available on Eight.”

Under Cronkite, Arizona PBS also will serve as a journalistic “teaching hospital,” tapping into the talents of advanced students in journalism and other disciplines who work under the guidance of top professionals from the ASU faculty and Eight staff to provide rich, new and innovative broadcast and digital content.

“A leading journalism school joining forces with one of the nation’s largest PBS stations at a university known globally for its leadership in innovation is a powerful and potentially game-changing combination,” the ASU president said. “We will be able to serve Arizonans on new levels while providing a national testing ground for new approaches to digital storytelling, audience engagement and revenue models to help serve a news industry that needs to rapidly adapt in the fast-changing digital world.”

Cronkite – a digital news leader

Since ASU made the Cronkite School a free-standing college in 2005, the school has been at the vanguard of a movement in journalism education to create highly immersive, professional programs in which students create journalism products under the guidance of top professionals recruited onto the faculty from some of the nation’s leading newsrooms. Harvard University documented Cronkite’s leadership role earlier this month in Nieman Reports.

Like a teaching hospital in medical education, these immersive professional programs provide intensive learning environments for students, important services to the community and the ability to experiment and innovate. In this case, the community service is providing critically needed, in-depth journalistic content to readers and viewers.

“We have called this a ‘teaching hospital’ approach to journalism education, but until now, we haven’t had the hospital,” said Christopher Callahan, dean of the school and university vice provost. “Now we do – a multiplatform media organization in one of the nation’s largest media markets.”

Cronkite leaders will spend the next few months designing the new enterprise, starting with combining the school’s immersive professional programs with Arizona PBS.

An expanded version of the school’s TV newscast, Cronkite NewsWatch, which covers public policy news around the state, will give Arizona PBS one of the nation’s only daily local PBS newscasts. A new study by the Radio Television Digital News Association found that only 16 of the nation’s 170 PBS stations have some kind of daily local public affairs programming. And most of those are not newscasts but public affairs interview shows, such as Eight’s award-winning “Arizona Horizon.”

Some of the other established Cronkite professional programs that will become part of Arizona PBS include multiplatform daily news bureaus in Phoenix, Washington and Los Angeles, which provide news coverage to professional media outlets across the region; an innovation lab that creates new digital media products for clients; the community engagement Public Insight Network Bureau that serves news organizations nationally; and the Carnegie-Knight News21 investigative multimedia initiative, whose publishing partners include The Washington Post and NBCnews.com.

Cronkite plans to add new immersion programs in business reporting and sports within the next six months, and will look to other disciplines across the university to create other professional programs within Arizona PBS.

The future of news

“As a veteran newsman now on the Cronkite faculty who has been immersed in the reconstruction of American journalism, I could not be more excited,” said Leonard Downie Jr., the former executive editor of The Washington Post who helps lead the News21 program. “This is a very important development, not just for journalism education and the development of outstanding journalists for tomorrow, but also for the transformation of the news media in the digital age.

“The future of news depends on the kind of ‘teaching hospital’ innovation and training that the creative combination of the Cronkite School and Arizona PBS will make possible,” Downie said. “At the same time, it promises to provide residents of the Phoenix area and much of the rest of Arizona with significant public service journalism in a university-based non-profit model that could serve as a blueprint for universities and public broadcasting stations everywhere.”

ASU also hopes other media organizations will bring their ideas to Cronkite to experiment on the Arizona PBS platforms.

“There remains a tremendous need for reinvention and disruptive innovation in today’s news industry,” Callahan said. “Our Arizona PBS initiative can provide a place where commercial news operations can try out their ideas.”

Kelly McCullough, a Cronkite alumnus and general manager of Arizona PBS, said his team is excited about Eight becoming a more integrated part of the university while continuing to serve Arizonans at the highest levels.

“We will continue to proudly bring Arizonans all of the quality programming they want and deserve,” McCullough said. “And now, as part of the Cronkite School, we will be able to develop new local content to complement our current signature PBS programs – everything from ‘Arizona Horizon’ and ‘Horizonte’ to ‘PBS NewsHour,’ ‘NOVA’ and ‘Downton Abbey.’”

Arizona PBS reaches nearly 1.9 million households and 4.8 million people across 80 percent of the state. Located in the 12th-largest media market in the United States, it has more than 1 million weekly viewers and the 4th-highest prime-time viewership per capita among the nation’s major market PBS stations. Eight also has the 2nd-largest viewership of the 57 university-operated PBS stations.

Reporter , ASU Now

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