The height of the aerosol layer, or aerosol layer height (ALH), is a critical factor in assessing how aerosols affect weather, climate, and air quality. Accurate measurement of ALH helps to improve the understanding of aerosol-cloud interactions and supports surface air quality assessments. Traditional remote sensing methods often face challenges when measuring ALH over oceans due to the complex nature of aerosol vertical distribution and their optical characteristics. These difficulties drive the need for more advanced instruments that can reliably measure ALH, which is vital for improving climate models and refining atmospheric corrections.
Researchers from the University of Maryland and the University of Iowa led the study, which was published in the 'Journal of Remote Sensing' on July 23, 2024 (DOI: 10.34133/remotesensing.0167). The study assessed the ability of NASA's PACE satellite, launched earlier in 2024, to measure ALH using the Ocean Color Instrument (OCI). It focused on OCI's sensitivity to the oxygen A and B absorption bands, validating results with proxy data from the TROPOMI instrument.
The study used OCI's measurements from the oxygen A and B bands to retrieve ALH. Researchers employed radiative transfer simulations to analyze how these bands respond to vertical aerosol profiles, with a particular focus on smoke and dust events. Two key channels - the 762.5 nm band in the oxygen A band and the 690 nm band in the oxygen B band - were identified as highly sensitive to changes in ALH. Validation efforts using TROPOMI data aligned closely with measurements from CALIOP lidar, showing an error margin of 0.49 km for smoke and 0.31 km for dust. This confirmed that OCI can measure ALH with precision, offering significant improvements in aerosol monitoring over oceans.
"This research highlights OCI's potential to accurately measure aerosol layer heights, improving atmospheric correction and enhancing our understanding of aerosol behavior," explained Dr. Xiaoguang Xu, the study's lead author. "The oxygen absorption bands provide valuable data that can refine our approach to monitoring aerosol dynamics."
These accurate measurements of aerosol layer heights from OCI observations promise substantial benefits for climate studies, atmospheric correction, and the monitoring of aerosols. The methods developed in this study lay the foundation for future algorithms, which will further enhance the quality of data used in scientific research and environmental management.
Research Report:Potential of NASA's Plankton, Aerosol, Cloud, and Ocean Ecosystem (PACE) Satellite Observations in the Oxygen Bands for Determining Aerosol Layer Height over Ocean