A Supercomputer Waters the Lawn

Smart Irrigation: A Supercomputer Waters the Lawn

Satellite control of company and municipal irrigation systems, based on custom weather data, saves billions of gallons of water nationwide

By Ingfei Chen  |

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In Silicon Valley the Campbell Union School District's sprinklers used to dutifully water the soccer fields and gardens at 12 campuses even during spring showers. Temporarily shutting off each of the 45 irrigation control boxes, by hand, wasn't worth the custodians' time. But in 2009 the district installed new "smart" controllers that automatically adjust daily watering to the weather. Each box, fitted with a microprocessor and antenna, receives local real-time weather information by satellite from the WeatherTRAK climate center supercomputer run by Petaluma, Calif.–based HydroPoint Data Systems, Inc.

On one April morning after a three-day rainstorm, Campbell Union's facilities supervisor, David Radke, checked the status of the controllers by logging in toWeatherTRAK.net The service had put the district’s irrigation network on pause when the storm began. According to WeatherTRAK's math, the network would not need to resume watering for eight to 11 days.

If needed, Radke can reprogram the controllers from his Web account, but because his crew has carefully customized each box's settings, he finds that "there's really not a whole lot to do. That's the beauty of it." The soccer fields look better than ever, yet in 2009 WeatherTRAK slashed Campbell Union's water use by 39 percent and cut its utility bills by $108,000, recouping the installation expenses nearly twice over.

With most sprinkler systems, property owners set the traditional controller—basically a timer—to irrigate at specific intervals. Often, too much water is lost to evaporation during hot weather or to runoff during cool weather, which can also carry chemicals into the local watershed or ocean. Because outdoor irrigation can suck up 50 percent or more of urban water consumption, smart irrigation services have caught on in drought-prone western states like California, where water prices are relentlessly rising. (Occasional big floods don't help the long-term problem.) HydroPoint now has more than 8,000 clients using 24,000 of its smart controllers, including Walmart, Coca-Cola, Hilton, Jack in the Box and the University of Arizona as well as the cities of Charleston, S.C., Houston and Santa Barbara. In 2011 customers are projected to save 64.4 billion liters of water and over $111 million in water expenses, as well as 68 million kilowatt-hours of water-pumping electricity.

The technology is still going through growing pains, but HydroPoint has solved several daunting weather-forecast and modeling challenges that help it deliver just the right amount of water at the most effective time.

Water by satellite
Founded in 2002 in Petaluma 65 kilometers north of San Francisco, HydroPoint has engineered what appears to be the most sophisticated weather-based irrigation system among a growing list of competitors. The company built its primary climate-modeling center outside of Salt Lake City, programming a supercomputer to simulate local weather for every square kilometer across North America—all just to water the grass. The center communicates via a two-way satellite link with control boxes that operate distinct zones of a client's irrigation system. Wires running underground from the outdoor boxes open and close valves in the water lines. Every night the climate center broadcasts local weather-related data to a microprocessor inside each controller, which runs software that uses the information to compute precisely how much and when to water its zones, customized to one of 18 plant types as well as other factors like soil type and ground slope.

The boxes can talk back, too. For example, Campbell Union installed additional wireless rain sensors (fixed to an exterior building wall) that, on detecting moisture, signals controllers, which put irrigation on hold and notify the climate center.

A WeatherTRAK prototype went live in 2003, starting with one-way satellite service in California. Two-way Internet-based communications became available in 2006, allowing a client to adjust thousands of controllers across multiple properties, all from one Web account. Monthly subscription fees today range from $4 to $18.75. The service is a prime example of the nascent field of water information systems that analyze real-time data to tackle water management issues—data that until recently has been sorely lacking in the industry. "You can't manage what you don't see," says HydroPoint co-founder Chris Spain.

Really local forecasts, in real time
Spain and his colleagues jumped into the business by buying a local irrigation-controller company and bringing on board its owner, Mike Marian, a self-taught engineer. Marian (who subsequently left HydroPoint in 2006) had patented the idea of using paging signals to transmit information to controllers about evapotranspiration(ET)—the amount of water soil loses to evaporation as well as transpiration by plantsgrowing there. Marian's system used free ET data from the nearest state weather stations, maintained for farmers by the California Irrigation Management Information System.

The entire state, however, had only around 120 stations. Simply averaging ET values from the two nearest stations (as farmers often did) could be misleading, because microclimates even a few kilometers apart can produce substantially different values. And although property managers could buy their own mini weather stations, those were less reliable.

The fledgling HydroPoint team instead boldly explored a cutting-edge alternative: using measurements from public weather stations across the U.S. to model an accurate ET for any location, down to a square kilometer—without having an actual station or sensors on-site. And doing it every night.

Dan Dansereau, a computer scientist who worked on high-resolution weather modeling at Utah State University in Logan thought it could be done. But he says he told Marian and Spain "You're going to need a big-ass computer," before he joined them as HydroPoint's chief scientist. Dansereau recalls one prominent colleague warning, "It's never going to work."

Indeed, modeling proved a complicated task. The team wanted to use the most accurate method for estimating ET, the Penman–Monteith equation, which factors in temperature, wind, solar radiation and relative humidity. But the trick to deriving real-time ET everywhere would be creating those four input parameters for each of the 19.2 million one-square-kilometer grids across the continental U.S. and Canada.

Dansereau's plan was to model the parameters using the same highly sophisticated (and public) forecasting software that the U.S. Air Force relied on, called theMesoscale model, or MM5, created by Pennsylvania State University and the National Center for Atmospheric Research (NCAR) in Boulder, Colo. Running MM5 at a daily one-square-kilometer resolution nationwide would take such tremendous computing power that no one had attempted it. Every day the climate center had to download millions of real-time data points via satellite from the National Oceanic and Atmospheric Administration (NOAA) and other public sources. That included surface observations collected hourly from ground weather stations, ocean buoys and weather balloons around the world, global satellite-imaging data every 15 minutes, and hourly Doppler radar data for the U.S. In addition, the MM5 program required 256 categories of local ground information such as topography, soil, vegetation and land use.

To manage the data avalanche, the HydroPoint engineers wrote proprietary code to organize and shovel it into databases. But they were still "really stymied" because MM5 required a lot of manual data entry, recalls co-founder and vice president Peter Carlson, who along with Dansereau literally typed in parameters every day. To streamline the process, they devised automated programs so the model could run itself from a single script.

Making forecasts accurate
A second major obstacle was verifying accuracy. How would the engineers know if WeatherTRAK's ET calculations were right? "This whole idea of 'ground truth' is a pretty complicated one," Spain says.

First, MM5 itself "was susceptible to garbage in–garbage out," Spain notes, because ground weather readings can themselves be wrong. The answer was writing a heuristic algorithm that crawls 24/7 through the incoming data and weeds out anomalous readings. For example, if the program detects an impossibly big swing in temperature or humidity readings from one hour to the next from the same weather station, that data is disqualified. Dansereau and Carlson later programmed similar verification steps into a more advanced successor to MM5, the Weather Research and Forecasting model (developed by NCAR, NOAA and partners), which the NationalWeather Service relies on. The result of HydroPoint's version of that model, which it runs today, is a "virtual weather station" for each square kilometer in North America. The outputs for temperature, wind, solar radiation and relative humidity are then funneled into the calculations of ET values, which are transmitted to customers' controllers by 8 P.M. Pacific time.

The second part of the accuracy problem was validating whether WeatherTRAK's numbers were on target. The engineers, focusing initially on California, realized they could check their daily results against actual ET measurements reported by the state's 120 weather-station array, which were published the following morning. "We process our data and publish the answers," Dansereau explains. "Then we get to check tomorrow to see how accurate our answers were." If WeatherTRAK finds an error or gets better information after the fact, it re-runs the model for past days, and can send retroactive corrections to controllers to continually ensure accuracy.

A glass half full—or more
A third key hurdle for HydroPoint was converting ET values into an irrigation schedule that would keep grass and plants in optimal health. The company developed scheduling software for the smart controllers that factors in ET plus 19 ground parameters entered by the client: from plant and soil types to sprinkler-head model. If a lawn's maximum water supply were the equivalent of a full glass of water, the goal is to let the level dwindle to half-full before topping the glass off again, Carlson says.

The WeatherTRAK system has continued to evolve. One ongoing challenge was rain. The company has always advised installing a rain switch that turns off the controllers when precipitation is detected. Since 2007 WeatherTRAK has also analyzed Doppler radar data to approximate the amount of rain that has accumulated on each square kilometer. The climate center roughly predicts the moisture depletion rate by subtracting the estimated daily ET loss for each grid, thus determining how long the irrigation pause should last—information that is sent to the controllers.

Supercomputing the savings
HydroPoint today runs WeatherTRAK on a blade  supercomputing cluster with two teraflops of number-crunching power. Jimy Dudhia, an atmospheric physicist at NCAR, who helped develop the Weather Research and Forecasting model, says it is surprising that HydroPoint can calculate real-time ET at such a fine-grain resolution across the U.S. The calculations require more computing power than the National Weather Service's 12-kilometer-resolution forecasts. "In terms of science, it's on the front end," Dudhia says.

Others also see ET modeling as the way to go. Managers of California Irrigation Management Information System, for example, have developed their own method for simulating ET values statewide. They post the free spatial data online, but it only covers California, and only at a two-square-kilometer resolution.

As with any weather modeling results, HydroPoint's won't be perfect. But does the computing footwork pay off? Michael Dukes, a University of Florida agricultural engineer who has studied various smart irrigation systems, says HydroPoint can be accurate under optimal conditions, but notes that other leading smart irrigation companies have also devised innovative solutions. For example, Rain Bird Corp.'s ET Manager controller—which, like HydroPoint, earned top scores on a standardized irrigation industry test—estimates ET from hourly data received wirelessly from private local weather stations. Dukes believes ET Manager might do a better job than WeatherTRAK of factoring in rainfall, using a tipping-bucket gauge on a client's site that quantifies precipitation more reliably than most rain sensors.

Still, HydroPoint can quote two dozen independent studies showing that WeatherTRAK curtailed water use by anywhere from 14 to 82 percent. But how much you save depends on how much you were wasting. A major study that tracked 2,294 California sites using 14 different brands of smart controllers found only a disappointing 6 percent average decline in water consumption in the first year. Nearly 57 percent of the sites saved water—but another 42 percent actually used more.

One explanation is that some landscapes were previously under-irrigated, so their usage rose, says civil engineer Peter Mayer of Aquacraft, a Boulder-based firm that conducted the California study. And if an irrigation system has leaky valves, high-end controllers may not help much. The study noted that HydroPoint's controllers, when averaged, reaped no savings the first year. Spain says that's because most of the devices were installed incorrectly. After Los Angeles's water agency fixed installation problems, the WeatherTRAK controllers reduced water use by roughly 16 percent.

The bottom line is that landscape contractors and property owners have to be educated about setting up and adjusting smart irrigation systems. Installation troubles are a real stumbling block, Mayer says. "We're kind of in the VCR-era of smart controllers, where nobody knows how to program it properly." Nevertheless, Mayer sees the evolving technology as a key conservation tool. The U.S. Environmental Protection Agency's Water Sense program plans to begin issuing labels for smart controller brands that pass efficiency certification by the end of this year.

From HydroPoint's perspective, the biggest barrier is the status quo of old habits that waste cheaply priced water. Now that rates are going up, attitudes are changing. The water crisis, Spain says, "is truly going to be the biggest issue of the century."

ABOUT THE AUTHOR(S)

Ingfei Chen is a freelance writer in the San Francisco Bay area. Her articles on neuroscience, medicine and ecology have appeared in The New York Times, Smithsonian and Science.

How to Avoid Retirement

By Lucas Laursen

"It used to be that when you retired your title became X emeritus. That doesn't help you when you write up a grant application." - Anthony Norman

When biochemist Anthony Norman earned tenure at theUniversity of California (UC), Riverside, he thought he'd never have to apply for a job again. But that was before he retired.

Norman, a professor emeritus, continues to run the laboratory he started in 1963. But he recently became a professor of the Graduate Division, a title reserved for retirees who "are fully engaged in research and/or other departmental and campus activities," his new appointment letter says. Norman, who will draw his pension instead of a salary, believes the new position will help his post-retirement research career. "It used to be that when you retired your title became X emeritus. That doesn't help you when you write up a grant application," Norman says. In contrast to professor emeritus, professors of the Graduate Divisionprove their value every 3 years by passing the same departmental merit review used to grant pay raises to regular faculty members. "We have to jump through the same hoops as everyone else," he says.

Some universities, such as Norman's UC Riverside, are changing their policies to harness the skills of aging researchers. Others are not. The United States, Canada, Australia, New Zealand, and now the United Kingdom have all banned mandatory retirement. But Japan and many European governments still allow employers and funding bodies to restrict access to employment or funding opportunities for researchers eligible for retirement pensions. In response, some researchers leave before their universities ask them to.

Feature Special on Retirement

Like any other career step, retirement benefits from early planning. Last week freelance writer Vivienne Raper gave a low-down on how to map the route to retirement. This week freelancer Lucas Laursen describes the solutions some senior researchers have found around mandatory retirement ages.

One is immunologist Klaus Rajewsky. When he faced mandatory retirement in 2001 from the University of Cologne in Germany, Rajewsky moved to Harvard Medical School in Boston, where he continues to work full-time as an endowed chair in pediatrics and a professor of pathology. Next year, Rajewsky plans to return to Germany, where some institutions are making it easier for exceptional retirement-age researchers to stay active.

By any other name

One way to put off retirement is to obtain one of the emerging class of contracts that enable researchers to continue to work after retirement, assuming your institution offers them. The professor of the Graduate Division position at UC Riverside, for example, is very flexible, Norman says. A similar position at UC Berkeley, known as professor of the Graduate School, allows senior researchers to retain their colleagues' respect by letting them focus on what they're good at, says Jack Kirsch, a 76-year-old biophysical chemist at UC Berkeley, who retired from his departmental professorship at age 71 and took the title of professor of the Graduate School. Kirsch continues to pursue research and has started teaching a freshman seminar on art. "Clearly, I don't have the influence I used to," Kirsch says. But "people still come to me to ask about enzymes."

Anthony Norman (CREDIT: Anthony Norman)

Some European countries with a default retirement age, an age above which employers can force staff into retirement, have proposed alternatives to traditional retirement. In Germany, institutes such as the Helmholtz Centres and states such as Niedersachsen are offering research fellowships to researchers who have retired from their official jobs. In the Netherlands, sociologist Siegwart Lindenberg of the University of Groningen negotiated a 10-year extension that started at age 65, his university's default retirement age. He is paid from his pension and has a research grant from the university. He remains eligible to apply for new grants, though he believes that "the chance of getting them is lower once you are above 65."

Lindenberg started talking to his departmental colleagues 2 years before his impending retirement. "The reaction was, 'No, we can't do that because it's against the rules,' " he recalls. It was against the rules, but it was not against the law: The Netherlands allows workers to continue working beyond age 65. Lindenberg presented his dean with evidence of how he was still useful to the university, including a list of recent publications and continued invitations to collaborate. It took about a year to turn his dean into an ally and another year to persuade the university to agree to an unusual contract that allows him to focus on his research. "When you stay on, they let you concentrate on your stronger points rather than on [departmental administration] duties," he says.

Siegwart Lindenberg (CREDIT: Siegwart Lindenberg)

Such new roles offer professors a chance to redefine the final years of their careers. They are encouraged to recognize their limits and abide by them. Lindenberg, for example, says he won't take on new Ph.D. students anymore but will help supervise those of his colleagues. Sacrificing some power to younger colleagues may be a fair price to pay to keep doing research, Kirsch suggests. "In a way, it hurts your ego to lose power, but it's as it should be."

Jumping ship -- with a lifeline

Some places still enforce mandatory retirement policies, or at least apply pressure. Sometimes the pressure is informal: Colleagues suggest that a senior professor hand over the reins to a particular course, Kirsch says, or they stop offering to collaborate on research projects. Other times the pressure comes from the national legal framework or from institutions' standard practices. Rajewsky was offered an opportunity to stay at Cologne and keep his lab space, but the offer was subject to short-term approvals by his colleagues. He refused.

Jack Kirsch (CREDIT: Jack Kirsch)

In such cases, the best options are elsewhere, at times within the same country. In Japan, most national universities force researchers to retire at 65, but there are some exceptions. At Kyoto Prefectural University of Medicine, neurophysiologist Minoru Kimura faced mandatory retirement at 63. He left when he was 62 for Tamagawa University in Tokyo, which made him director of its Brain Science Institute and won't ask him to retire until he is 68. "Many active people are unhappy to stop working," Kimura says.

Making a successful move requires a lot of logistical planning. Kimura brought colleagues and laboratory equipment to Tamagawa. It helped that he was already collaborating with people there and that two of his postdocs were eager to follow because "it is not easy to find a different institute in the same field," he says. Things went so smoothly that "2 months was enough for me to restart in this institute." Now he is working at least as hard as he was before.

Minoru Kimura (CREDIT:Tamagawa University/ Minoru Kimura)

Some researchers who left home to avoid mandatory retirement are finding opportunities to come back. Regional governments are starting to reconsider rules and offer workarounds. Last year, one such change allowed Rajewsky, aged 74, to accept an offer to return. He insisted on one condition, which his new institution, the Max Delbrück Center for Molecular Medicine in Berlin, granted: "I would not go back to a job which had a time limit."

The keys to finding, obtaining, and moving smoothly into post-retirement jobs, older researchers say, are strong connections with colleagues and a compelling track record. Bringing in your own funding can also help: Rajewsky will return to Germany with a 5-year, €2.5 million Advanced Investigator Grant from the European Research Council. Outside offers also can remind your institution of your value, says Lindenberg, who obtained a concurrent part-time post at Tilburg University in the Netherlands. Still, he says, "a better strategy is to show that you're still very valuable to the university" by presenting a portfolio and a plan for how you'll contribute to your department.

Further information for senior researchers

The Max Planck Institutes in Germany support senior fellows and so do some individual Helmholtz Centres. The German region of Niedersachsen also supports some senior researchers.

In the United Kingdom, the University of Cambridge has an agreement for retired researchers to hold grants.

The Organisation for Economic Co-operation and Development compiles pension age data by country

Releasing the Potentials of Senior Scholars and Scientists: Emerging Productivity in a New ERA, co-edited by Henk A. Becker, Johannes J. F. Schroots

Finding showing human ancestor older than previously thought offers new insights into evolution

Posted by Biomechanism 

Modern humans never co-existed with Homo erectus—a finding counter to previous hypotheses of human evolution—new excavations in Indonesia and dating analyses show. The research, reported in the journal PLoS One, offers new insights into the nature of human evolution, suggesting a different role for Homo erectus than had been previously thought.

Meet 'Mrs Ples' who was unearthed in Sterkfontein, South Africa in 1947. Her whole skull was found and it is believed she lived 2.5million years ago. Sediment traces found on the inside of her skull indicate to scientists that she died by falling into a chalk pit.

The work was conducted by the Solo River Terrace (SoRT) Project, an international group of scientists directed by anthropologists Etty Indriati of Gadjah Mada University in Indonesia and Susan Antón of New York University.

Homo erectus is widely considered a direct human ancestor—it resembles modern humans in many respects, except for its smaller brain and differently shaped skull—and was the first of our ancestors to migrate out of Africa, approximately 1.8 million years ago. Homo erectus went extinct in Africa and much of Asia by about 500,000 years ago, but appeared to have survived in Indonesia until about 35,000 to 50,000 years ago at the site of Ngandong on the Solo River. These late members of Homo erectus would have shared the environment with early members of our own species, Homo sapiens, who arrived in Indonesia by about 40,000 years ago.

The existence of the two species simultaneously has important implications for models about the origins of modern humans. One of the models, the Out of Africa or replacement model, predicts such overlap. However, another, the multiregional model, which posits that modern humans originated as a result of genetic contributions from hominin populations all around the Old World (Africa, Asia, Europe), does not. The late survival of Homo erectus in Indonesia has been used as one line of support for the Out of Africa model.

However, findings by the SoRT Project show that Homo erectus’ time in the region ended before modern humans arrived there. The analyses suggest that Homo erectus was gone by at least 143,000 years ago—and likely by more than 550,000 years ago. This means the demise of Homo erectus occurred long before the arrival of Homo sapiens.

“Thus, Homo erectus probably did not share habitats with modern humans,” said Indriati.

The SoRT Project’s investigations occurred in Ngandong and Jigar, two sites in the “20-meter terrace” of the Solo River, Indonesia. The sediments in the terrace were formed by the flooding of the ancient river, but currently sit above the Solo River because the river has cut downward through time. The terrace has been a rich source for the discovery of Homo erectus and other animal fossils since the 1930s.

As recently as 1996, a research team dated these sites of hominin, or early human, fossils to as young as 35,000-50,000 years old. The analyses used a technique that dates teeth, and thus provided ages for several animals discovered at the sites. However, other scholars suggested the sites included a mixture of older hominins and younger animals, raising questions about the true age of the hominin remains.

The goal of the SoRT team, which included both members of the 1996 group and its critics, was to understand how the sites in the terrace formed, whether there was evidence for mixing of older and younger remains, and just how old the sites were.

This species of sub-human - Homo rudolfensis - was found in Koobi Fora, Kenya, in 1972. The adult male is believed to have lived about 1.8million years ago. He used stone axes ate meat and plants and lived on the wooded edge of Lake Turkana in Eastern Africa.

Since 2004, team members have conducted analyses of animal remains, geological surveys, trenching, and archaeological excavations. The results from all of these provide no evidence for the mixing of older and younger remains. All the evidence suggests the sites represent just a short time period.

“The postmortem damage to the animal remains is consistent and suggests very little movement of the remains by water,” explained Briana Pobiner, the project’s archaeologist and a paleoanthropologist at the Smithsonian Institution’s National Museum of Natural History. “This means that it is unlikely that very old remains were mixed into younger ones.”

In addition, clues from the sediments exposed during excavation suggest to the projects’ geoarchaeologists, Rhonda Quinn, Chris Lepre, and Craig Feibel, of Seton Hall, Columbia, and Rutgers universities, that the deposits occurred over a short time period. The teeth found in different excavation layers at Jigar are also all nearly identical in age, supporting the conclusion that mixing across geological periods did not occur.

“Whatever the geological age of the sites is, the hominins, animals, and sediments at Ngandong and Jigar are all the same age,” said project co-leader Susan Antón.

The team applied two different dating techniques to the sites. Like earlier work, they used the techniques—U-series and Electron Spin Resonance, or ESR—that are applied to fossilized teeth. They also used a technique called argon-argon dating that is applied to volcanic minerals in the sediments. All three methods use radioactive decay in different ways to assess age and all yielded robust and methodologically valid results, but the ages were inconsistent with one another.

The argon-argon results yielded highly precise ages of about 550,000 years old on pumices—very light, porous volcanic products found at Ngandong and Jigar.

“Pumices are hard to rework without breaking them, and these ages are quite good, so this suggests that the hominins and fauna are this old as well,” said project geochronologist Carl Swisher of Rutgers University.

By contrast, the oldest of the U-series and ESR ages, which were conducted at Australian National University by Rainer Grün, are just 143,000 years.

The difference in the ages means that one of the systems is providing an age for something other than the formation of the sites and fossils in them. One possibility is that the pumices are, in fact, reworked, or mixed in, from older rocks. The other possibility is that the ESR and U-series ages are dating an event that occurred after the sites were formed, perhaps a change in the way groundwater moved through the sites.

Either way, the ages provide a maximum and a minimum for the sites – and both of these ages are older than the earliest Homo sapiens fossils in Indonesia. Thus, the authors concluded that the idea of a population of Homo erectus surviving until late in time in Indonesia and potentially interacting with Homo sapiens seems to have been disproven.