BOUNDARY LAYER PROCESSES
Our atmosphere extends from the Earth’s surface to the edge of outer space more than 60 miles (100 km) above ground level. But many of the processes that drive and control the behavior of the atmosphere occur at or near the surface. Scientists at ATDD perform investigations to measure and predict how atmospheric processes in the near surface boundary layer affect weather, climate and air quality.
ATDD operates a permanent forest micrometeorology research station at the Chestnut Ridge Environmental Study site, located on the U. S. Department of Energy reservation near Oak Ridge National Laboratory. The site hosts a 60 m tower that extends 20 meters above the top of the surrounding predominately oak-hickory forest. The tower supports a variety of environmental and atmospheric measurements related to air-surface exchange between a deciduous forest canopy and the lower atmosphere.
Many previous studies have focused on tornado formation over the Great Plains of the U. S., but relatively little research has been conducted on this topic over the southeastern U. S. In the Southeast, land surface characteristics differ considerably from the Great Plains, including more variable terrain and larger and denser forested areas. These characteristics can impact the development, structure and intensity of thunderstorms and tornados and make forecasting of tornados more difficult in this area. ATDD scientists participate in large-scale measurement campaigns to better understand the processes of tornado formation in the Southeast.
Forecasting when and where thunderstorms will occur is a challenging forecasting problem. In the absence of large scale forcings (e.g., cold fronts and other synoptic features), land surface forcings that lead to the formation of thunderstorms (termed convective initiation or CI by scientists) can be very subtle and occur at timescales ranging from a few minutes to an hour. Improving the representation of these forcings in weather forecast models requires high temporal resolution meteorological measurements, field experiments, and state-of-the-art high resolution computer models of the atmosphere.
The advent of small-unmanned aircraft systems (sUAS) for atmospheric research promises to provide new opportunities to make meteorological measurements in the lowest layer of the Earth’s atmosphere. ATDD uses this technology to measure changes of temperature and relative humidity with altitude, map the temperature and character of the Earth’s surface, and perform storm damage assessment in a way never before available that is faster, cheaper, and safer than using manned aircraft.
Scientists at ATDD have conducted research in cooperation with energy companies to enhance the efficiency of wind turbines by improving the forecast capabilities of wind speeds at the hub height of large wind turbines. ATDD’s expertise in the measurement and prediction of the behavior of the atmosphere near the Earth’s surface has led to increased wind turbine efficiencies through improved operational support for wind energy production.