The area where air and sea meet plays a vital role in the exchange of heat, greenhouse gases, and momentum between the ocean and atmosphere. Tobias Kukulka, the newest physical ocean science and engineering (POSE) faculty member in the College of Earth, Ocean, and Environment (CEOE), is working to gain a better understanding of this important region.
Before joining the college in January as assistant professor of POSE, Kukulka was a post-doctoral scholar at Woods Hole Oceanographic Institution, where he investigated the influence of surface waves on the oceanic boundary layer.
In the oceanic surface boundary layer, nutrients, plankton, temperature, and momentum are mixed by turbulent processes. Surprisingly, surface waves affect such mixing: Waves break and interact with the surface currents to energize the water and enhance air-sea interactions. Breaking waves also inject air bubbles, which can then dissolve and greatly facilitate gas transfer between the ocean and atmosphere.
Understanding these processes on a relatively small scale will improve global climate and regional weather models, Kukulka said.
“A climate model usually cannot resolve phenomena smaller than a few kilometers,” he explained, “but there’s a lot of action in a cubic meter. Imagine a violently breaking wave that stirs everything up — current climate models don’t take into account these enhanced mixing effects due to waves.”
In his doctoral dissertation at the University of Rhode Island, Kukulka developed a coupled model of wind and waves, which provides a perspective on how wind is weakened by enhanced friction due to waves. Better predictions of wind drag are urgently needed for improving hurricane forecasts, according to Kukulka.
At UD he plans to use this coupled wind and wave model to incorporate wave effects into a computational approach called “large eddy simulations.” In contrast to typical weather and climate models, this approach resolves the large turbulent eddies of the oceanic boundary layer. It is, therefore, a powerful tool for investigating in detail turbulent air-sea interaction processes. Kukulka also plans to extend the modeling framework to include different physical, biological, and chemical components, such as bubbles.
Kukulka said he looks forward to forming interdisciplinary collaborations with scientists and students at UD. In particular, he said he plans to take advantage of UD’s laboratory facilities and coastal resources, which will help him apply new insights on air-sea interactions for practical environmental predictions.
For more about CEOE, visit www.ceoe.udel.edu.