Carnegie Mellon University
January 03, 2013

Perfecting a Climate Model: CEE’s Peter Adams Collaborates with Scientists in Bologna

Perfecting a Climate Model: CEE’s Peter Adams Collaborates with Scientists in Bologna

The Truth About Aerosols: Adams is one of five Carnegie Mellon professors who make up the inter-departmental CMU Center for Atmospheric Particle Studies (CAPS). He was eager to clear up a common misconception about aerosols, one of many topics studied at CAPS. “When most people hear about aerosols polluting the atmosphere, they think of the aerosol spray can. However, aerosols are simply particles floating around in a gas such as the atmosphere. The spray can is one example, but it’s only the tip of the iceberg.”The Truth About Aerosols: Adams is one of five Carnegie Mellon professors who make up the inter-departmental CMU Center for Atmospheric Particle Studies (CAPS). He was eager to clear up a common misconception about aerosols, one of many topics studied at CAPS. “When most people hear about aerosols polluting the atmosphere, they think of the aerosol spray can. However, aerosols are simply particles floating around in a gas such as the atmosphere. The spray can is one example, but it’s only the tip of the iceberg.”

Recently, CEE professor Peter Adams exchanged Pittsburgh pierogies for Italian tortellini and spent a year on sabbatical in Bologna, Italy. Adams, who researches atmospheric science and climate modeling, was collaborating on several projects with Italy’s Consiglio Nazionale delle Ricerche (National Resource Council, or CNR), an internationally renowned network of government labs headquartered in Rome. 

Adams was drawn to CNR because of its scientists’ expertise in a unique research technique called Nuclear Magnetic Resonance, or NMR. NMR allows scientists to visualize the basic structure of an organic molecule, and is a valuable analytical tool in atmospheric chemistry. “An organic molecule has many different, complicated components,” Adams explained. “However, each component has hydrogen atoms hanging from it, and those hydrogens look different based on what part they are attached to. NMR only sees the molecule’s hydrogen, and because their ‘hydrogen shift’ reveals what they are attached to, you indirectly learn something about the molecule’s structure.”

Adams was particularly interested in NMR because CNR had been using the technique to gather data on atmospheric composition. Adams hoped to use their data to evaluate a global climate model he had developed which predicted the proportion of atmospheric particles from various emissions sources. If his model’s predictions closely aligned with CNR’s atmospheric data, it would mean he was on the right track. However, since the CNR data and Adams’ models “didn’t really speak the same language,” as Adams described it, the trick would be understanding what essential pieces of information they could distill out of CNR’s data to test his model. 

Adams and CNR researcher Stefano Decesari worked together to pinpoint what feature of his model to test. Ultimately, they decided to compare CNR’s measurement of atmospheric levels of aromatics (compounds produced by biomass burning) with the levels predicted by his model, which were based on estimates of the amount of biomass being burned globally. The results of the comparison were encouraging. “They were in the right neighborhood. It was like a proof of concept.” 

Working with CNR researchers gave Adams a valuable opportunity to compare his climate models to experimental data. He noted that collaborations between modelers and experimentalists are a key feature of successful research, saying, “You can learn more from someone who is doing something different than you.” Living in Bologna also gave Adams the chance to exercise his foreign language skills. “I told the scientists on the first day, science in English, everything else in Italian,” he said, grinning. “Thankfully, they’re very patient people.”

Next Steps

Since returning from Bologna, Adams has been working to fine-tune his climate model using his findings from the collaboration with CNR. Inspired by the parallel between his model’s predictions and CNR’s data on aromatics, he hopes to collect long-term atmospheric data in a key region such as the Amazon. “If we had a year’s worth of data that showed the difference between the dry season (when all of the burning occurs) and the wet season, that would allow us to test our model’s ability to reflect seasonal changes.” 

Ultimately, Adams hopes to use his climate model to identify how extensively particulate matter offsets global warming. “Greenhouse gases warm the planet, but particles tend to cool it by reflecting sunlight away from the earth. We know that particulate pollution has offset between 20 and 80 percent of global warming, but that’s a big range. Our model is trying to pinpoint that exact percentage, which is the Holy Grail of climate modeling.” 

Knowing this percentage would allow scientists to understand the climate change that has occurred over the last hundred years, and more importantly, to project what might happen over the next hundred years. Adams explained that the number affects what happens if the world is able to clean up its particle pollution. “If the particles are offsetting eighty percent of global warming rather than twenty, warming will get about five times worse in a short amount of time. So this competition between greenhouse gases and particles is an issue for predicting the future, but it is also crucial in interpreting the past.” A better understanding of the link between atmospheric particle levels and global warming could improve climate change models and inform public policy on pollution.

For more on the climate research being conducted in the Adams lab, see his website.

Peter and Amy in Venice Professor Adams and his wife, Amy Rigsby, also took time to visit some of Italy's sights. Here they are enjoying the canals of Venice. 
Bologna A view of the city of Bologna.
group Pictured is the research group Professor Adams collaborated with in Bologna.