When a paleontologist looks for a fossil, she chooses a likely location and digs. But what does an atmospheric scientist do when looking for an airflow pattern? If you're DRI's Dr. Vanda Grubisic you use a numerical model (a computer-based mathematical reconstruction) to simulate it; and you join a team of international researchers in the field experiment. Grubisic will take part in the Mesoscale Alpine Project (MAP)-a large experiment involving several European countries, Canada, as well as U.S. agencies-to be conducted this fall in the Alps of Italy and Austria. In an effort to better understand how the Alps affect weather in the region, the project will focus on two areas: rain and snow related to the mountains (orographic precipitation), and the mechanics of airflow over the mountains. Grubisic particularly interested in looking at a phenomenon known as potential vorticity (PV) banners, which form in conjunction with atmospheric wakes on the downwind side of orographic (mountain) barriers. Think of a rock in a stream, and the wake that forms behind it. A similar phenomenon occurs as airflow is disturbed by an obstacle such as a tall mountain. Prediction models have shown potential vorticity banners forming downstream of Alpine peaks.
"We want to confirm what we see in the model predictions," explains Grubisic, "and look at the structure and scale of PV banners, and whether they are stationary or intermittent." Finding and studying the PV banners will help researchers identify and understand effects of atmospheric wakes.
Precipitation will be another important focus of MAP. "The Europeans are very keen on improving prediction of the severe weather and flash floods that have been a cause of serious material damage and loss of lives primarily on the southern side of the Alps," says Grubisic. During the project, Grubisic will be primarily working from Innsbruck, Austria on the northern side of the mountains, with occasional trips to Milan, Italy on the southern side.
In the summer of 2000, Grubisic expects that some of the preliminary results from MAP will be reported at the American Meteorological Society Mountain Meteorology Conference which she is chairing.
Grubisic has been with DRI since February, coming to the Institute from the National Center for Atmospheric Research in Boulder, Colorado. She was educated in her native Croatia (B.Sc. from University of Zagreb) before earning her Ph.D. from Yale University. Grubisic hopes that her research in the Alps will help lead to a better understanding of airflow and precipitation in northern Nevada. "In the long term, I would like to develop a research project focusing on orographic precipitation in Nevada's complex terrain," says Grubisic. "And I look forward to simulating some of the characteristic airflow patterns and winds here, like the Washoe Zephyr."
Jackie Allen
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