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Sisters, Oregon
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Portable weather research lab comes to Sisters
By Craig F. Eisenbeis

Roj Marchand and Jennifer Comstock are manning a weather station in Sisters.

First came the six foot chain link fence enclosure at Sisters Airport, and people wondered, "A really big dog run, perhaps?" Then came the porta-potty, and "Maybe a very small minimum security prison," was one of the more amusing conjectures.

When the truck arrived with all the antennas, gizmos and gadgets, there was only one possible conclusion: Mad scientists.

As it happens, they don't seem to be all that mad, but they sure enough turned out to be scientists.

Roj Marchand, with a Ph.D. and post-doctoral studies in atmospheric science is one of them.

Marchand is a Senior Research Scientist for the Atmospheric Radiation Measurement Program with the U.S. Department of Energy.

The portable weather research station is a part of the agency's Pacific Northwest National Laboratory at Richland, Washington.

Marchand and a contingent of fellow scientists are nearing the end of a month-long project in Sisters that is taking a look at the area's clouds and precipitation patterns.

"Our interest is in studying clouds and the properties of clouds to understand the climate and energy budget of the earth," said Marchand.

He explained that his group is working closely with the University of Washington to verify and further develop weather forecasting models for the region.

Sisters was selected because the project required a site close to the Cascade Mountains but not in the midst of the heaviest belt of precipitation.

The station verifies and coordinates its measurements with research aircraft that periodically fly above the site to directly sample precipitation and cloud particles.

The aircraft are provided by the University of Washington and the National Oceanic and Atmospheric Administration.

The flights follow the Santiam River and overfly Santiam Pass on their way to Sisters.

"We're not so much interested in how much precipitation ends up on the ground," said Marchand, "but in how much water is in the clouds."

Regional weather models are an important part of the overall process of forecasting weather systems but are only as good as the microphysical schemes on which they are based.

The Sisters project is designed to help improve the base data on which the forecast models are built.

The portable lab contains a variety of instruments, some of which are active and send out signals.

The principal active devices include a type of radar that is used for seeing into clouds, and something called LIDAR (Light Detection and Ranging).

Instead of using microwave pulses, like radar, LIDAR sends out pulses of light to help analyze cloud structure.

Most of the instruments are passive and simply receive incoming information. Among these are devices which measure microwave and solar radiation, light, thermal energy, and infra-red light.

Jennifer Comstock, who holds a Ph.D. in Atmospheric Science, is another of the several scientists involved in the project.

She explained that, by combining LIDAR and infra-red data they are able to measure the optical density of the clouds and determine the number and density of water particles.

"It's more like a small piece of the total climate picture," she said.

Marchand said that the University of Washington will use the study's data to evaluate the accuracy of current weather models and make any adjustments.

People interested in learning more about the project can log onto http://improve.atmos.washington.edu for further information.

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