Modeling Matters

Science Wednesday – Modeling Matters: See Mack Run the Half-Marathon

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

By Tanya Otte

Lots of people like running. I’m not one of them…unless it involves running models! Since I was hired, I’ve been a part of a team that develops and runs models to help understand interactions between meteorology, natural and anthropogenic (“human-caused”) emissions, and air quality. The heartbeat of the air quality model development occurs in EPA’s Atmospheric Modeling and Analysis Division and with the Community Multiscale Air Quality Modeling (CMAQ) system, the Nation’s premier air quality simulation model.

CMAQ (pronounced “see mack”), a state-of-the-science tool for air quality modeling, was first publically released in 1998 by the EPA, and it now boasts a worldwide community of more than 3,700 users in 95 countries. CMAQ has been used by the EPA and by state environmental agencies to support air quality policy decisions. Nations around the world use CMAQ to study air pollution issues and create air quality management strategies. CMAQ provides daily ozone forecast guidance issued by the National Weather Service. The CMAQ user community spectrum spans academia, government, and private industry. CMAQ is one of the most widely respected modeling tools of its genre.

This month, EPA is releasing CMAQ 5.0. Major updates to CMAQ, like this, occur about every three years. CMAQ 5.0 incorporates the latest developments in air quality science, and it can be used to examine the interactions between air quality and climate. One of the biggest advances in CMAQ 5.0 is a comprehensive and synchronized coupling of meteorology and air chemistry to more accurately simulate the feedbacks between weather and air pollution.

This month, EPA also celebrates the 10th anniversary of its partnership with the Community Modeling and Analysis System (CMAS) Center. CMAS has been the conduit for public releases of CMAQ, and they have been instrumental in brokering international scientific contributions to CMAQ. CMAS has provided training and online support for the CMAQ community, and they host an annual workshop dedicated to exchanging the most updated scientific findings. This year’s workshop takes place October 24-26, and more than 250 participants have registered.

CMAQ just completed the half-marathon (measured in years, not miles). With a strong team at the EPA and a diverse and growing community of international collaborators, CMAQ will be running the race for many years to come!

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

Editor’s Note: The opinions expressed in Greenversations are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

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.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.