UNIVERITY PARK, Pa. — Improving forecasting for a host of severe weather events may be possible thanks to a more comprehensive method for measuring the Earth's boundary layer depth, developed by Penn State researchers.
The boundary layer is the layer of atmosphere that is closest to the Earth, less than one mile from the surface. Because it is the layer that is most affected by the convective heat from the Earth's surface, it is responsible for sudden weather shifts such as thunderstorms.
The boundary layer gets its name because it traps things such as pollution, smog, smoke from forest fires, and other airborne particles from rising higher in the atmosphere. As sun warms the surface of the Earth, it also warms the air. This warm air rises, deepening the boundary layer.
In research published in the Journal of Atmospheric and Oceanic Technology, researchers demonstrated how 159 currently operating weather radars could, in real time, track boundary layer depth, which constantly ebbs and flows. That is important because boundary layer depth is currently measured twice daily by launching weather balloons from about 100 locations nationwide.
In addition to being gathered in real time, radar measurements give a more complete analysis of the boundary layer by sending out vertical and horizontal impulses to log if snow, rain or insects are present.
Inaccuracies in boundary layer assessment lead to significant errors in forecasts, said John Banghoff, graduate student in meteorology, Penn State. Banghoff said those inaccuracies are leading to poor forecasting results.
"If we can improve the accuracy of the initial information, that's going to get a better forecast in the future," Banghoff said. "Boundary layer estimates are off by a factor of two in most models, which is very significant. If you have 200 percent error in your model, it's not going to do a very good job."
In addition to severe weather modeling, understanding boundary layer depth could improve models for air pollution and wildfire forecasting. A 2009 report by the National Research Council highlighted limitations of boundary layer depth monitoring as a major concern, citing that other monitoring methods should be explored.