Modeling aerosol-cloud interactions Down Under

Fascinated by extreme weather events from a young age, Noah Asch knew he wanted to pursue a career that could have a downstream impact on climate change. From storm chasing with his dad to being captivated by the movie “Twister,” Asch’s early interests in climate and weather eventually led him to pursue a Ph.D. in civil and environmental engineering at Carnegie Mellon after graduating from the University of Washington with a degree in Atmospheric Science. Little did he know that his passion would not only prompt him to move across the country, but it would also lead him to conduct research on the other side of the world.

Asch’s research under the mentorship of Hamish Gordon, associate professor of chemical engineering, focuses on modeling how aerosols interact with the atmosphere and form clouds. Aerosol-cloud interactions can influence the formation, size, and longevity of clouds, resulting in downstream warming and cooling effects under various scenarios. However, there is a significant amount of uncertainty in the weather and climate model the research group uses, especially when it comes to the Southern Ocean, a region Asch notes to be the most inaccessible of the world's ocean basins.

“It is quite difficult to get to this region and take measurements, which are essential to validate the model’s output,” Asch said.

To help reduce this model uncertainty, Asch spent two weeks in New Zealand as a part of a German-led field campaign called HALO-South.

“This campaign consisted of several flights around the Southern Ocean to try to better understand the atmospheric processes that occur at high latitudes,” Asch said. “When you don’t have a lot of measurements, it is hard to ensure the accuracy of a model, so that’s why we are interested in the Southern Ocean. In particular, we want to better predict aerosol-cloud interactions in this region.”

As part of the campaign team, Asch was instrumental in planning flight patterns for missions and even served as a mission PI on a research flight during the campaign.

“I would sit in the cockpit of the plane with the pilots and inform them on where to fly based on what I was seeing and the input we received from operators on the plane and the ground,” Asch explained. “It was around six and a half hours of flying total where I was instructing the pilots on where to go within the bounds of our flight plan.”

As a fourth-year Ph.D. student, Asch reflects on his time at CMU and is grateful for the supportive community he has found on campus and within his department. “If you’re considering graduate school, be really sure that you are passionate about what you are doing,” Asch said. “Carnegie Mellon has been a great place for graduate school. The professors are well-connected and brilliant at what they do. I think it’s the community that I have made here that will be extremely helpful for future collaborations in my field.”

After graduating from CMU, Asch has aspirations to pursue research at a federal or national laboratory.

Gordon, along with Ph.D. students Eric Giuffrida and Kate Johnson, also ventured Down Under for the HALO-South campaign.