Our department's research focuses on understanding the atmospheric "engine" that connects the weather we experience near the ground to the edge of space, 100 kilometers up. The atmosphere is constantly moving, driven by powerful waves that are much larger and more energetic than ocean waves. These include Planetary Waves (vast systems generated by continents and mountain ranges) and Gravity Waves (smaller ripples caused by storms and winds flowing over hills). These waves transport massive amounts of energy and momentum from the lower atmosphere all the way into the mesosphere. When these waves break, they generate extreme turbulence, heating of the atmosphere and dramatically shifting global circulation patterns.
To track this complex vertical transport, we use highly specialized ground-based systems, primarily powerful Lidar instruments. By observing how light scatters off atmospheric molecules, we can precisely measure temperature, density, and wind speeds up to the mesosphere. Crucially, our scientists also develop sophisticated sensors to be carried on sounding rockets that fly directly into the upper atmosphere. These rocket sensors are essential for taking in-situ (direct) measurements, particularly capturing the fine-scale details of atmospheric turbulence—the key process that drives vertical mixing. Our research quantifies how much energy is transferred by these waves and how turbulence dissipates it, allowing us to model the entire atmosphere as a single, coupled system. This detailed understanding of atmospheric coupling is fundamental to predicting space weather and ensuring we accurately understand how changes in the lower atmosphere directly impact the fragile environment near the boundary of space.
Our skies are filled with tiny particles that have an enormous influence on the atmosphere and climate. We investigate the microphysical properties, origin, and fate of these aerosols and particles across the middle atmosphere, covering both natural and human-made sources. Every day, Earth is bombarded by space rocks, which ablate upon entry to create Meteor Smoke Particles (MSP)—nanometer-sized dust that drifts down into the stratosphere. These particles are essential for global atmospheric processes, influencing everything from chemistry to the global radiation budget. We use novel Lidar methods to track these tiny particles deep into the atmosphere, allowing us to precisely characterize their shape and size, and distinguish them from other particles like volcanic ash. This is a complex task due to their small scale and low concentration, requiring advanced optical techniques.
This tracking is critical because MSPs act as the essential building blocks, or nucleation sites, for the highest clouds on Earth: Noctilucent Clouds (NLCs). These shimmering blue clouds are highly sensitive indicators of atmospheric change. Our ongoing research investigates how both natural MSPs and new anthropogenic aerosols (from spacecraft re-entry or rocket exhaust) change the overall particle budget. We study how these changes affect NLC formation, revealing subtle signals of long-term environmental change in the upper atmosphere. Understanding the chemical and physical processes governing these particles is key to solving how they influence the climate system, particularly in regions where they interact with water vapor to form clouds.
As satellite launches and space travel rapidly increase, our atmosphere faces a new frontier of pollution: metal contamination from space debris and re-entering spacecraft. With the anticipated deployment of thousands of more satellites in the coming decade, the scale of this problem is rapidly growing, posing a measurable threat to the composition of the mesosphere and upper stratosphere. When satellites eventually deorbit and burn up, they release tons of exotic metals, such as Lithium, Nickel, Copper, and Iron, into the atmosphere. Our department is leading the international effort to track and understand this emerging environmental threat, providing critical data to the global scientific community.
To monitor this influx, we develop and utilize highly specialized multi-color resonance lidars. These cutting-edge instruments are designed specifically to detect these new anthropogenic metal species at extremely low concentrations at altitudes around 90 km. This detection is a major technical challenge, as the unique optical signature of each metal must be isolated with high precision against the natural background. Our research then goes a step further by focusing on the chemical fate of these metals. We investigate how they are transformed through atmospheric reactions, how long they stay suspended in the atmosphere, and how they interact with existing atmospheric chemistry and natural aerosols. This work provides crucial scientific evidence to establish baseline contamination levels, assess the potential environmental impact on ozone and cloud formation, and inform global regulatory bodies on the long-term consequences of this new source of global pollution, ensuring the sustainability of the near-space environment for future generations.
The mesosphere and lower thermosphere (MLT), located roughly 50 to 100 kilometers up, are exceptionally sensitive to climate change. This region acts as a giant thermometer for the upper atmosphere, responding dramatically to changes in greenhouse gas concentrations. While increasing carbon dioxide (CO2) traps heat and warms the air near the ground, it paradoxically leads to dramatic cooling in the MLT as the increased density of CO2 allows thermal energy to radiate out to space more efficiently. Our research is dedicated to rigorously measuring and verifying this predicted high-altitude cooling effect, which is one of the clearest and most robust signatures of global climate change.
We maintain some of the longest and most continuous atmospheric datasets in the world, with Lidar records spanning over 30 years. This dedication to long-term monitoring is vital because it allows us to filter out natural, cyclical atmospheric variations (like solar activity, volcanic eruptions, and seasonal changes) from permanent, forced climate change trends. We precisely quantify changes in temperature, winds, and other key dynamic parameters in the upper atmosphere. By confirming the patterns of MLT cooling and relating them to observations of phenomena like Noctilucent Clouds (which become brighter and occur more frequently as the mesosphere cools and moistens), we provide essential scientific evidence that validates global climate models across the entire vertical extent of the Earth's atmosphere. This comprehensive approach is necessary to understand the full, complex impact of greenhouse gas emissions on the entire planet.
Discoveries at the frontier of atmospheric science are only possible through continuous advancement in technology and instrumentation. Our department acts as a center for applied physics and engineering, dedicated to designing and building the next generation of specialized instruments for remote sensing and in-situ measurements. This includes tackling technical challenges in making systems more efficient and robust for deployment in harsh environments. We are constantly advancing our Lidar technology, focusing on key challenges such as making laser systems more powerful, compact, and reliable so they can eventually be deployed on satellites or sounding rockets to provide extended or global atmospheric coverage.
A major focus is on Rocket Sensor Development: we design, test, and precisely calibrate the complex scientific payloads—new generations of specialized in-situ sensors—that are launched aboard sounding rockets. These instruments must be engineered and hardened against the extreme conditions encountered during a rocket flight, including intense vibration, temperature extremes, and the vacuum of spaceflight. They provide unique, high-resolution measurements of atmospheric composition and dynamics unattainable by remote sensing methods alone. To ensure reliable, continuous scientific output from all our instruments, we also dedicate significant effort to developing the advanced software for instrument control. This crucial software enables automated, day-and-night operations of our Lidar network at remote sites and includes robust data processing pipelines necessary for the rapid ingestion and analysis of the massive, terabyte-scale amounts of data collected daily. Furthermore, this development work drives innovation in the field of scientific automation.