Clouds are constantly changing and studying them is challenging, at best. But that is just what Kathleen Schiro does: studies clouds. Schiro believes that a better understanding of cloud formation, particularly convective precipitation (known as thunderstorms), can be key in understanding climate and weather forecasting. In a world changing rapidly due to climate change, Schiro’s new models can help communities see in real-time how weather extremes affect them.
Schiro is an atmospheric scientist in UVA’s Department of Environmental Sciences and studies clouds at scales ranging from individual clouds to those spanning the entire globe. Entering her fifth year at UVA, Schiro and her students have brought fresh energy to an important field. Her work is rooted in theories of atmospheric convection: the complex physics of thunderstorms, heavy precipitation, and cloud formation.
“I want to improve the prediction of heavy convective precipitation,” Schiro said, “by studying how they grow. If we understand how thunderstorms form and we can accurately represent them in climate and weather forecasting models in our present climate, we can place more confidence in how models suggest they’ll behave in response to greenhouse gas increases in the future.”
The data Schiro uses for these studies is extremely varied.
“We rely on field campaign observations, satellite data, and dynamical models to piece together how thunderstorms develop. We want to get at the physics. Why do they grow? Why do they rain as much as they do? Why do they pop up here, but not there?”
Technology is a critical piece of Schiro’s work, especially earth-orbiting satellites. Schiro has access to highly sophisticated satellites operated by NOAA as well as NASA’s precipitation radars. These data sets help Schiro revise the models that climate and weather forecasts rely on to represent deep convection.
Meteorologists and climate scientists face complex challenges in refining their predictions. Climate events are highly sensitive to different small-scale processes but the atmosphere is also responding to a large-scale increase in greenhouse gases.
“For example, we have thirty-some climate models that contribute to IPCC projections,” Schiro said, referring to the Intergovernmental Panel on Climate Change, formed in 1988, “and they all represent convection differently. If we use different statistical models to represent deep convection in climate models, in certain instances, we can drastically change the cloudscape and the climatology.” Her group explores how these sensitivities affect our predictions of changes to the climate and climate extremes with increasing greenhouse gases.
The largest source of uncertainty in the amount of global warming expected from a given greenhouse gas is the uncertain response of clouds.
“In fact,” explained Schiro, “my group has recently discovered strong relationships between changes in high-altitude ice clouds – that form and change, at least in part, due to deep convection – and the amount of global warming we can anticipate from a given greenhouse gas... [This is] critically important to our understanding of anthropogenic climate change.”
Funding from the Environmental Institute has helped Schiro create a bridge between what many would consider theoretical work and practical application. It is an opportunity to move research to action.
With EI support, she engages in interdisciplinary work with hydrologists and engineers across the university, studying what local climate change means for flooding (even down to the street level) and for water resources, infrastructure, and engineering. To do this, she and her group again use climate models, but they tailor them to be more useful for answering questions about climate change at a local level.
“We have low-resolution global climate models where we can pump the whole atmosphere with CO2 and see how the climate responds at larger scales, but it’s too expensive to run global climate models,” Schiro admitted. So, instead, her team plans to “dynamically downscale” larger-scale climate information. In a unique approach, Schiro will use this kind of weather forecasting model over specific regions of interest – such as Virginia – to study changes to precipitation extremes and associated impacts locally.
Schiro has been encouraged by public awareness of and growing attention to climate change.
“The alarm bells are ringing,” she said, “and there’s been a rapid uptick in interest in climate even since I was an undergraduate student. The public’s perception of changing extremes is no longer naïve.”
She believes that some of this shift in public perception is due to important work going on beyond her lab.
“We have a better, more coordinated way of attributing wildfires, droughts, and floods to climate change. And that’s critical because climate change is knocking at our door.”