Science Wednesday: Modeling Matters—Where could it go, and how do we know?

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

By Tanya Otte

Recently, powerful tornadoes ripped through central North Carolina. My yard, more than five miles from the nearest tornado touch-down, collected remnants of someone else’s losses: wads of insulation, fragments of ceiling tiles, a shard of vinyl siding, a shingle. It was fascinating that this debris could travel so far. Where on the path of the tornado did it come from?

In high school, we are introduced to Isaac Newton and his three laws of physics. Like many of you, I sat through it and acknowledged that this is nice to know, but I really did not appreciate the power of Newton’s laws. It turns out that those three laws are pretty important.
When something is injected into the atmosphere, it has to go somewhere. This includes debris from a tornado, exhaust from your car, “that smell” from the factory, and all other stuff regardless of its size. It may change form from interactions with water, sunlight, and other “things” in the air and/or with temperature changes. So where could it go, and how do we know?

To understand how the atmosphere moves the stuff that is put into it, scientists use “models”—collections of equations built from what we know.

Newton’s laws are three of the basic tenets of what we know for building atmospheric models. We also use other things we know, such as the composition of the atmosphere and how things in it interact with each other and with sunlight. We use measurements of weather and air quality to start our models and to check the quality of our predictions.

Models help scientists understand the complex interactions of atmospheric pollutants with weather and climate. Models are used to support regulations on emissions that protect human health and conserve resources. Thousands of scientists worldwide use models developed by the EPA to understand, predict, and reduce air pollution. Needless to say, models are rather powerful scientific tools.

I still don’t know where the debris in my yard originated, but I could use a model to figure it out.

About the author: Tanya Otte, a research physical scientist, has worked at EPA in atmospheric modeling and analysis since 1998.