Aerosol particles smaller than 150 nm, previously undetectable by satellites and balloon sensors, dominate the surface area for chemical reactions in the lower stratosphere.
A study published in Science (2026, DOI: 10.1126/science.adw8939) reveals that aerosol particles smaller than 150 nm, previously undetectable by satellites and balloon sensors, dominate the surface area for chemical reactions in the lower stratosphere. The findings indicate that these particles are rich in organic compounds and play a significant role in Earth's radiation budget.
Key Details
The research was part of NOAA's broader effort to understand Earth's radiation budget, which measures incoming solar energy and outgoing terrestrial energy to assess climate trends. Stratospheric particles at altitudes of 10–50 km influence the radiation budget, but their evolution over time is poorly understood due to observational gaps.
Instruments on satellites and balloons cannot reliably detect particles smaller than 150 nm because they scatter too little light (satellites) or are too heavy to lift (balloons). During the 2023 Stratospheric Aerosol processes, Budget and Radiative Effects (SABRE) campaign, researchers used a custom instrument aboard a high-altitude aircraft to measure the size and composition of aerosols in the lower stratosphere. The data showed that small particles (<150 nm) were numerically dominant and, based on analysis of larger particles, are likely rich in organic compounds.
Significance
- The study provides the first detailed measurements of these small stratospheric particles, which had been theoretically predicted but not directly observed at this scale.
- The findings suggest that current models of stratospheric chemistry do not accurately represent these particles, potentially leading to incomplete understanding of climate processes.
Attribution
- Ming Lyu, research scientist at the University of Colorado Boulder and NOAA Chemical Sciences Laboratory, led the study and noted that the particles were previously undetectable.
- Alison Bain, aerosol researcher at Oregon State University, commented via email that the stratosphere is more chemically complex than previously thought.
- Frank Keutsch, professor of atmospheric science at Harvard University and a SABRE participant not involved in this work, stated that the research provides an entirely new picture of the stratosphere.