WKU students participate in ground breaking study

Two Western Kentucky University meteorology students lent their hands in an unforgettable, groundbreaking project this past summer.

They traveled to Nebraska to investigate how irrigation affects precipitation.

Nebraska is one of the most irrigated places in the world. Between Lincoln and York, Nebraska lies the Big Blue River. Irrigated agriculture sits on the west side of this river, while the east side is primarily not irrigated.

A 100 by 100 kilometer swath of land, with the Big Blue River running right through the middle of it, was the perfect spot to set up a research camp for the Great Plains Irrigation Experiment, or GRAINEX for short, this past summer.

For 15 days straight, once in the middle of May at the start of irrigation season and again in July during peak irrigation season, six students monitored the atmosphere’s behavior. They focused specifically on the boundary layer where the ground is interacting with the atmosphere through a process called evapotranspiration. The GRAINEX project required an array of equipment to collect daily observations.

“There was two profilers, two sounders, and 12 flux stations, three DOWs. We had NASA flew the L-band microwave antenna to catch the land surface conditions between observation points, and then we had roughly 60 to 65 observation stations throughout the region,” recalled Dr. Eric Rappin, research scientist at the Kentucky Climate Center at WKU.

Students and scientists from WKU, the University of Alabama – Huntsville, University of Nebraska – Lincoln, University of Colorado – Boulder, the Center for Severe Weather Research and the National Center for Atmospheric Research all came together to man that equipment and collect continuous data.

Most of the equipment was used to measure correlations between things like temperature and momentum near the surface. Weather balloons were launched every two hours to monitor vertical changes in the atmosphere. NASA also assisted by mapping the land between observation stations using airborne, remote sensing radio frequency technology to measure spatial patterns of soil moisture. The two WKU students chosen to participate in this data collection process, C.J. Padgett and Brandon Wasilewski, manned one of the Doppler on Wheels, or DOW for short, mobile radar units.

“We were both on the afternoon shift which was from noon- to 9:30/10 o’clock at night. But then when there was severe weather we would either go in early in the late morning or later in the evening. So one night I was out in the field until about 2 a.m.,” said Padgett.

They collected about two Terabytes of data from 5-7 computers on the DOW each day.

“It was a very amazing experience. It was very nice to see the real world applications of collecting data and seeing how it can be used in everyday life. Just communicating with a lot of people about how/what they do with irrigation. Everything can affect the weather,” said Wasilewski.

From all of the data they collected, it will take about six months to convert it from raw data to data suitable for scientific studies. Once this data is usable, staff at WKU and scientists at the National Center for Atmospheric Research will work together to put it into numerical models for meteorologists to get a better understanding of how irrigation directly affects precipitation. This topic is becoming more and more important because with a growing population comes a growing demand for food, which means increased irrigation. The results of this study will also be relevant to us here in Kentucky.

“You do have land surface changes in western Kentucky that sort of mimic the role of irrigation. So irrigation is directly wetting the surface, whereas when you have land surface changes, you’re doing it indirectly because of different characteristics, some soils are wetter than others. So you can see different amounts of surface fluxes based on the different kinds of surface characteristics. So what we’ve done in Nebraska is certainly more than applicable here in the commonwealth,” stated Dr. Rappin.

In the coming months and years, the results of this study will be used to improve agricultural planning as well as forecasting methods across the United States, and eventually the world.