Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Any way you slice it, warming climate is affecting Cascades snowpack

14.05.2009
There has been sharp disagreement in recent years about how much, or even whether, winter snowpack has declined in the Cascade Mountains of Washington and Oregon during the last half-century.

But new research leaves little doubt that a warmer climate has a significant effect on the snowpack, as measured by water content on April 1, even if other factors keep year-to-year measurements close to normal for a period of years.

Water content can vary greatly depending on temperature and other conditions at the time of snowfall. Typically an inch of snow at temperatures near freezing will contain significantly more water than an inch of snow a colder temperatures.

"All things being equal, if you make it 1 degree Celsius warmer, then 20 percent of the snowpack goes away for the central Puget Sound basin, the area we looked at," said Joseph Casola, a University of Washington doctoral student in atmospheric sciences.

That means that even in years with normal or above-normal snowfall, the snowfall probably would have been even greater except for climate warming. The finding has implications for various water-dependent resources, including drinking water supplies, fisheries, irrigation and hydropower, and it could be applicable to other areas of the Cascades in the Pacific Northwest.

Annual snowfall variability makes it difficult to plot a meaningful trend, Casola said. Starting in a year with high snow accumulation will imply a significant decrease over time, while starting in a year with average or low snow totals will imply little change or even an increase. So, for example, measuring from 1944 to 2005 shows just a slight decline in snowpack but changing the starting year to 1950 more than triples the decline.

However, the measurements also show a slight increase in the last 30 years, a period of significant climate warming. That is probably because trend measurements include declines from climate warming as well as increases and decreases from other factors. For example, several of the lowest-snow winters in the Puget Sound area were during El Niño years, while many of the highest-snow winters were during La Niña years. Those two climate phenomena in the South Pacific can have significant impact on Northwest weather. Likewise, the amount of snow can be affected by a long-term climate cycle in the North Pacific called the Pacific Decadal Oscillation, which changes between positive and negative phases on the order of every 20 years.

"Global warming can be reducing your snowpack over time, but other factors can mask the impact of the warming," Casola said. "Conversely, in a period of dry years global warming would tend to exacerbate the effects."

The new research used four different methods to examine decades-long records of water contained in Cascades snowpack in the central Puget Sound basin on April 1 of each year. Scientists used simple geometry to estimate temperature sensitivity of snowpack, made detailed analysis of seasonal snowpack and temperature data, used a hydrological model to examine the data, and analyzed daily temperature and precipitation measurements to estimate water content of snowpack on April 1.

"If you assume precipitation is the same every year and look at the effects of temperature alone, all the ways we examined the data converge at about a 20 percent decline in snowpack for each degree Celsius of temperature increase," said Casola.

He is lead author of a paper detailing the work, part of his doctoral thesis, which is being published online May 14 in Journal of Climate, published by the American Meteorological Society. Co-authors, all from the UW, are Lan Cuo, Ben Livneh, Dennis Lettenmaier, Mark Stoelinga, Philip Mote and John M. Wallace.

While there still is uncertainty in the trend data, people can expect to see lower spring snowpack more frequently in the future, with low-snow winters bringing low-flow summers, Casola said. Winter precipitation in the Cascades is likely to be similar to what is recorded now, but more of it will be rain.

Casola notes that businesses, resource manager, utilities and irrigators increasingly accept the notion of climate change, and many try to incorporate the information into long-term plans.

"Now they want to know, 'What does this mean for my operation?'" he said. "People are becoming more savvy to the issue of climate change. They want to be aware of changes that might be coming and to identify areas in their systems that perhaps need to be modified."

The work was funded by the National Science Foundation and the Joint Institute for the Study of the Atmosphere and Ocean at the UW.

For more information, contact Casola at 206-543-5754 or jcasola@atmos.washington.edu.

At the American Meteorological Society, contact Stephanie Kenitzer at 425-432-2192 or kenitzer@ametsoc.org

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu

More articles from Ecology, The Environment and Conservation:

nachricht How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>