Forecasting models that incorporate high-powered computers and satellite data may soon modernize the way Western states manage freshwater supplies. Several such models are currently under development. Dennis Lettenmaier, professor of civil and environmental engineering at the UW, will describe the role of science in Western water management Friday in San Francisco at the American Association for the Advancement of Science annual meeting.
A half-century ago, resource managers would ski or hike to mountain stations and measure the amount of water stored in the snowpack. They took a metal tube and inserted it in the snow, then weighed the tube to calculate how much water it contained. Today's electronic systems automate this process, but use a similar principle, Lettenmaier said.
"If you know how much snow is on the ground in the spring, you have a pretty good idea of how much runoff will occur during the spring and summer," Lettenmaier said. "That's something that's been used for a long time. The question is: can we do better than that?"
A new generation of hydrologic forecasting models integrate not only scattered, ground-based measurements of snow depth, but also satellite measurements of snow extent. The University of Washington's West-Wide Seasonal Hydrologic Forecast System is an example of such a model. It recalculates conditions every day using weather data and satellite images. UW's model incorporates atmospheric climate forecasts and produces forecasts of stream flow for up to a year into the future.
The overall aim is to provide computerized water forecasts equivalent to modern weather-prediction models. The new forecast methods incorporate a wealth of other climate information to produce results earlier in the season, more accurately and for situations that are outside the norm. These methods recalculate conditions every day by incorporating satellite images of snowcover and computing the influence of that day's temperature and precipitation.
Forecasts based on physical processes avoid the problems inherent in statistical forecasting methods that rely on historical patterns. For example, after unusually heavy snowfall in the Southwest in 2003, traditional forecast models predicted that the spring and summer runoff in Utah's Virgin River would be as much as 10 times its normal rate, values that didn't seem believable. In the case of drought, snow levels in 1977 were so low that forecasted runoff for some California streams was negative.
"It's a classic problem of extrapolating a line out past the end of the observations," Lettenmaier said. When current conditions don't look like anything previously seen, methods that are too closely related to historic patterns can fail.
Water managers are beginning to feel a crunch related to climate change, Lettenmaier said. Springtime melt now starts some 20 days earlier than a half-century ago, which is "pretty unequivocally" seen as a signature of climate change, he said. The shift results in a bigger gap between when the fresh water flows down from the mountains and when it actually is most needed in the height of summer. Climate change constitutes an additional challenge, on top of factors such as population movement, agriculture changes and water use changes, that managers must contend with.
Knowing the amount of water ahead of time lets people prepare for droughts or flooding. Building more reservoirs would help, in particular to handle earlier runoff, but the West is unlikely to see any more dams built, Lettenmaier said. Instead, people can use forecasts to decide which crops to plant, whether to drain reservoirs to prepare for flooding and how to allocate water resources early in the season.
Hannah Hickey | EurekAlert!
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology