Harmonized and high-quality datasets of aerosol optical depth at a US continental site, 1997–2018

Abstract

Aerosol optical depth (AOD) characterizes the aerosol burden in the atmosphere, while its wavelength dependence is a sign of particle size. Long-term records of wavelength-resolved AOD with high quality and suitable continuity are required for climate change assessment. Typically, climate-related studies use AOD products provided by several, and perhaps different, ground-based instruments. The measurements from these instruments often have different accuracy and temporal resolution. To preserve the advantages of these products (high quality) and to reduce their disadvantages (patchy records), we generate a merged dataset obtained from four instruments deployed at a US continental site in which a nearly-continuous AOD record is found at two wavelengths (500 and 870 nm) with high quality and high temporal resolution (1-min) for a 21-yr period (1997–2018). The combined dataset addresses: (1) varying data quality and resolution mismatch of the individual AOD records, and (2) the uncertainty of the merged AOD and its relevance for user-specified needs. The generated dataset will be beneficial for a wide range of applications including aerosol-radiation interactions.

Remote Sensing of Snow Parameters: A Sensitivity Study of Retrieval Performance Based on Hyperspectral versus Multispectral Data

“…For our configuration, fine mode aerosols have an optical depth of 0.212 and a single-scattering albedo of 0.948, while coarse mode aerosols have an optical depth of 0.026 and a single-scattering albedo of 1 at a reference wavelength λ = 500 nm. These values are consistent with values typically measured in the atmosphere [33].…”

Extended Aerosol Optical Depth (AOD) time series analysis in an Alpine Valley: A Comparative Study from 2007 to 2023

“…However, satellite retrievals face limitations due to their viewing geometry, where light traverses the atmosphere twice and reflects off the Earth's surface, complicating accurate measurement, whereas ground based remote sensing observations meet the World Meteorological Organization (WMO) traceability requirements in more than 95% of the measurements (Cuevas et al (2019)) and allow robust trend analyses (Kazadzis et al (2018)). High quality AOD time series are of special importance regarding climate observations (Kassianov et al (2021)). This study aims to deepen our understanding of aerosol behavior in the Alpine valleys of Innsbruck, Austria, and Davos, Switzerland.…”

Extended aerosol optical depth (AOD) time series analysis in an Alpine valley: a comparative study from 2007 to 2023

“…However, satellite retrievals face limitations due to their viewing geometry, where light traverses the atmosphere twice and re- flects off the Earth's surface, complicating accurate measurement, whereas ground-based remote sensing observations meet the World Meteorological Organization (WMO) traceability requirements in more than 95 % of the measurements (Cuevas et al, 2019) and allow robust trend analyses (Kazadzis et al, 2018). High-quality AOD time series are of special importance regarding climate observations (Kassianov et al, 2021). This study aims to deepen our understanding of aerosol behaviour in the Alpine valleys of Innsbruck, Austria, and Davos, Switzerland.…”