Keeping tabs on the planet
From the Arctic to outer space, Professor Joel Johnson's remote sensors have been deployed into a range of extreme environments to monitor climate and weather conditions.
Last winter his ultrawideband radiometer spent months measuring the thickness and salinity of Arctic sea ice as part of an international climate mission. Oguz Demir, an electrical and computer engineering graduate student in Johnson’s research group, traveled to the Arctic to operate the sensor aboard a ship that was intentionally frozen into the ice.
“It’s providing new information about how microwave radiometers can sense the thickness of sea ice,” Johnson said.
Scientists use radiometers to measure the natural microwave frequencies emitted by the Earth, Johnson explained. The data from these sensors measures soil moisture, sea temperature, sea ice coverage, snow thickness, weather and more.
“They’re important sensors used for weather monitoring, climate monitoring, oceanography and understanding the cryosphere,” said Johnson who has studied and advanced radiometer technology for more than 30 years.
As the inaugural Burn Jeng Lin and Sue Huang Lin Endowed ElectroScience Laboratory Professor, Johnson receives funding that enables him to advance his cutting-edge microwave remote sensing research for eventual use by organizations like the Office of Naval Research and NASA.
“It helps to have resources to pursue things that are at an earlier stage and develop them into future high-impact activity,” Johnson said.
Another of Johnson’s projects, which also happens to be Ohio State’s first satellite, launched in 2018. CubeRRT’s onboard technology removes radio frequency interference that can hinder researchers’ efforts to detect what’s happening on Earth from space.
“The problem is only getting worse over time,” Johnson explained. “The spectrum is getting more and more crowded, due to the continued rapid growth in demand for wireless services.”
Originally expected to orbit for one year, the satellite has been successfully operating in space for more than 5,000 hours so far and its processor technology could be used in future missions.
“The goal of the project was met within the first couple of weeks,” Johnson said. “But the longer something works in space, the more confidence you have in it.”
The professorship that supports Johnson’s work was established by a generous gift from distinguished alumnus Burn Lin and his wife Sue Lin. Burn earned his PhD from Ohio State in 1970 after working with his advisor, Professor Emeritus Stu Collins, at the ElectroScience Laboratory (ESL).
“I am grateful to ESL, my advisor, Prof. Stuart Collins Jr., and many other ESL professors for providing me with a good environment and the necessary support to learn and to acquire experience in research,” Burn said. “Making a gift to ESL is a way to express my gratitude.”
Johnson is also grateful for the ElectroScience Laboratory, which is what drew him to Ohio State in 1996. ESL is one of the largest radio frequency and optics research laboratories in the world where researchers are addressing the world’s most complex challenges, from climate change to hardware cybersecurity.
“When you want to take on these bigger projects that involve building things that go on airplanes or out on the sea ice and so on, you need a team of people. You can't do it alone. The ESL has a great team and great facilities,” he said.
“A lot of the components of all these systems were built in the lab and tested in the Compact Range. It really enables a lot of bigger research activities.”
