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Modeled for success: TCEQ meteorologists constantly seek to improve

Oct. 11 – Air quality forecasts critical for both public, agency missions

Among the many tools at his disposal, Weslee Copeland, the lead meteorologist for the TCEQ’s Monitoring Division, explains the modeling software he uses. The program, which he helped to develop, collects and analyzes atmospheric data to create a baseline air quality forecast.
Among the many tools at his disposal, Weslee Copeland, the lead meteorologist for the TCEQ’s Monitoring Division, explains the modeling software he uses. The program, which he helped to develop, collects and analyzes atmospheric data to create a baseline air quality forecast.

It’s not just the National Weather Service and television news programs that need the services of meteorologists.

The TCEQ’s Monitoring Division employs two, and they fulfill critical duties at the agency that go well beyond the typical meteorological predictions of daily weather conditions, such as temperature and precipitation.

Their work revolves around how air quality affects the environment and public health. Their most recognizable task is their daily air quality forecast that is published on the TCEQ’s website, shared through social media, and frequently used by news media. But their meteorological work is also vital to the daily missions of numerous other environmental workers performing a wide range of roles at the agency.

“Information is power, and the TCEQ makes it its business to get that information to people, so they can make informed decisions,” says the TCEQ’s lead meteorologist, Weslee Copeland, who has been with the agency for 12 years.

Copeland and Heather Wylie, the Monitoring Division’s other meteorologist, frequently collaborate on their forecasts to ensure they are as accurate as can be.
Copeland and Heather Wylie, the Monitoring Division’s other meteorologist, frequently collaborate on their forecasts to ensure they are as accurate as can be.

Copeland and Heather Wylie, the Monitoring Division’s other meteorologist, rely on a tool chest of state-of-the-art technology, including a geostationary satellite exit launched by the National Oceanic and Atmospheric Administration in March, the TCEQ’s own ambient air monitoring stations situated at sites throughout the state, and other data from various governmental agencies.

One of their most important tools is one that they developed themselves, with assistance from other technical experts at the TCEQ, over a four-year period: custom air quality modeling software, which they started to use in 2015 and have continued to refine and adjust since then.

A model program

This modeling software (aka a statistical regression model) uses aggregates and analyzes a vast amount of incoming atmospheric data. The system also incorporates information from weather modeling programs designed and operated by NOAA and the Naval Research Laboratory and constantly polls all available raw data, including satellite and air monitoring information.

The TCEQ’s model then performs sophisticated regression analyses to produce baseline air quality predictions, which Copeland and Wylie use to inform their final Air Quality Index and Ozone Action Day forecasts.

One of the steps that the meteorologists perform to see if anything is amiss with their modeling program is to doublecheck it against the predictions by NOAA exit and the Naval Research Lab models exit. If there are discrepancies, the meteorologists will review the processes and incoming data to make sure that everything is working correctly and all the numbers are accurate.

The TCEQ’s model sets itself apart from others by accounting for sea breezes and stalled fronts, Copeland says. This makes for a more accurate air quality forecast for Texas.

Also, this sometimes helps explain discrepancies in predicted levels of a category of air pollutant, such as ozone. Copeland provides two examples.

On one summer day, NOAA’s model predicted an ozone level of 83 parts per billion for the Dallas-Fort Worth Metroplex, but the TCEQ’s program forecast a 78. The actual level turned out to be 78. On another summer day, NOAA predicted that Houston would have an ozone level of 80 parts per billion, but TCEQ forecast a 57. The actual ozone level was 52.

The accuracy of the TCEQ’s modeling program has garnered notice. Copeland presented about it internally to other agency meteorologists and to air quality staff in August and at a national conference to fellow air quality forecasters in Washington, D.C., at the end of September.

The TCEQ’s modeling program is not a static, finished product. It is constantly being refined and adjusted as needed. New inputs are often incorporated, and sometimes old inputs are deleted.

“Our network is always changing, and our air quality model continues to improve,” Copeland says.

Satellite imagery and data are highly valuable in figuring out the day’s air quality forecast.
Satellite imagery and data are highly valuable in figuring out the day’s air quality forecast.

The Air Quality Index forecast

In addition to providing specialized forecasts—including ones that concern the potential impact of large events from elsewhere in the world, such as radiation fallout from the Fukushima nuclear-plant disaster in Japan—much of the focus of the Monitoring Division’s meteorologists is producing daily Air Quality Index forecasts.

Much like a typical weather forecast, the air quality forecast alerts when the prevailing conditions are less than ideal—often in the summer, when it’s hot and dry—such as high levels of ozone or particulate matter, including those caused by the occasional African dust storms that ravage the state with dust blown off the Sahara Desert and carried across the Atlantic on trade winds.

“We like to say, ‘Bad weather equals good air quality, and good weather equals bad air quality,’” Copeland remarks.

The TCEQ’s daily air quality forecasts are modeled after and predict the EPA’s Air Quality Index, which categorizes ozone and particulate matter (both PM2.5 and PM10) by color bars ranging from green (good) all the way to maroon (hazardous).

The actual Air Quality Index is an interpretation of what the air quality was after it is over.

“The Air Quality Index was developed by the EPA as a way to standardize the reporting of air quality in a particular area combining multiple pollutants,” Copeland says. “In other words, it’s a way to say the air quality in your area is good or moderate without having to go into details about which pollutant is dominant right now and throwing out a bunch of numbers that may confuse people. It was meant to be an index that summarizes air pollution.”

Each TCEQ air quality forecast provides specifics on every metropolitan area in the state, so a huge and varied amount of data goes into each one. The accuracy of the forecasts is a point of pride for the TCEQ’s meteorologists.

“We do a really good job with our forecasts,” Copeland says.

Like weather forecasts, the air quality forecast helps make for a more informed public.

“They can better plan their activities based upon that forecast,” Copeland says.

When needed, the meteorologists are responsible for issuing Ozone Action Days, which are transmitted by the National Weather Service. An Ozone Action Day is a special forecast that alerts the public when ozone will be potentially problematic.

Old-fashioned maps are also indispensable for air quality forecasts. Copeland says the map helps them visualize and discuss variable atmospheric conditions, such as the location of a stalled front.
Old-fashioned maps are also indispensable for air quality forecasts. Copeland says the map helps them visualize and discuss variable atmospheric conditions, such as the location of a stalled front.

Other vital duties at the TCEQ

While the public may be familiar with the Monitoring Division’s daily air quality forecast—even if some may not be aware of its origins—the Monitoring Division’s meteorologists also provide important contributions to the missions of other agency personnel.

They support regional investigators by providing forecasts that help them time certain investigations or conducting analyses that help them respond to odor complaints; advice the Monitoring Division on where to situate temporary air monitoring stations; contribute to the Air Quality Division’s studies on when to release ozonesondes (balloon-borne instruments that measure the vertical profile of ozone in the atmosphere) to measure the vertical profile of ozone in the atmosphere; and provide regional offices with agricultural burn forecasts, which indicate when conditions are optimal for such burning, as with the sugarcane fields of South Texas.

They also provide meteorological assistance when there are emergency events such as droughts, tropical storms, wildfires, and more. They also help validate data received through the agency’s various monitoring systems to ensure that incoming information is as accurate as possible.

“We are ready if needed,” Copeland says.

Challenges

Copeland and Wylie may have a lot of high-tech tools at their disposal, but those tools do not remove all their obstacles or challenges.

“In terms of the actual forecast itself, probably the most challenging thing for any meteorologist, whether you are forecasting the weather or air quality, is precipitation: the amount, the exact location, and the duration,” Copeland says.

“As you would expect, precip has a very big impact on air quality,” he says. “Generally, a heavy rain is going to improve air quality. That can really mess up a high ozone forecast. If storms you are expecting don’t develop, you might have a big ozone event that you weren’t expecting because, instead of storms, you have sunshine and warm temperatures.”

Another challenge with the forecasts is helping the public understand exactly what the air quality data means.

For instance, Copeland says people sometimes have a hard time differentiating between the TCEQ’s forecast and real-time air quality conditions, such as those shown by the EPA’s NowCastexit

Current conditions may indicate that the air quality is red, say for ozone, but the TCEQ’s air quality forecast had predicted yellow (moderate). Yet, both can be (and are often) correct.

Because of those differences, some will think that the TCEQ’s air quality forecast is inaccurate, but that is not usually the case, Copeland says. The reason is that an important factor in the final Air Quality Index is time.

For public health reasons, the regular Air Quality Index measures ozone over an eight-hour period, but poor current air quality may be brief and balance out over the eight-hour period. Warnings may be necessary for poor short-term air quality, Copeland says, but those numbers may be much higher than the average over the eight-hour period.

One thing we can be certain of: Whatever happens in the skies over Texas, the meteorologists of the TCEQ’s Monitoring Division will be keeping their eyes on it and keeping us informed.

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All photos TCEQ.