@ American University, Washington DC
Overview
Our research focuses on aerosols in the stratosphere and their role in the Earth's climate. We study aerosols from natural sources, such as volcanic eruptions and forest fires, and anthropogenic sources, such as fossil fuel burning and geoengineering. Most of our research is carried out with climate model simulations, but we also use satellite and in-situ measurements from aircraft- and ground-based instruments.
If you are interested in working with us, check out the Opportunities page and contact Prof. Aquila. If you already have a project in mind, please send me an email and we can discuss new opportunities and collaborations.
Eruption of Mt. Sarychev on June 12, 2009. ISS Crew Earth Observations Experiment and Image Science & Analysis Laboratory, Johnson Space Center via NASA Earth Observatory.
Volcanic eruptions
Volcanic eruptions suddenly change the composition of the atmosphere by emitting gases, ash, and sulfate particles. By changing the radiative budget and chemistry of the atmosphere, these volcanic aerosols cool the Earth's surface and warm the stratosphere, alter winds and precipitation patterns, and destroy stratospheric ozone, among other effects. Our research to date has focused on the impacts of the 1991 eruption of Mount Pinatubo on stratospheric winds and ozone concentrations, as well as on the role of volcanic eruptions in the satellite stratospheric temperature record. Currently, we are working on understanding the impact of eruptions on seasonal forecasts and on the composition of the lower stratosphere.
Stratospheric aerosols
Volcanic eruptions and geoengineering are not the only sources of aerosols in the stratosphere. In specific meteorological conditions, forest fires can generate pyrocumulonimbus clouds (pyroCb), thunderstorms that inject smoke in the lower stratosphere. Surface air pollution can be transported to the lower stratosphere through convective systems like the Asian summer monsoon. Additionally, meteoritic dust settles in the stratosphere from above. Generally, the largest perturbations of the stratospheric aerosol layer are associated with volcanic eruptions, but studies have shown how these other sources of stratospheric aerosols are more important than previously thought. Our lab is working on quantifying the role of these aerosol sources in the stratosphere aerosol budget.
PyroCb in Colorado. Luis Rosa, NWS San Juan PR.
Low visibility due to air pollution in New York City in 1973. Source: EPA Documerica "Then and Now Challenge"
Urban air quality
Fine particulate matter (or PM) is one of the main air pollutants. Exposure to high PM concentrations can cause serious health problems, especially in vulnerable populations. Our lab has been working with communities in Washington, DC to measure air concentrations of PM using low-cost air quality monitors hosted by local residents. Thanks to their low cost and ease of use, low-cost air quality monitors allow residents to gather real-time information on their exposure to air pollutants.