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SKYNET

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Handbook of Air Quality and Climate Change

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Abstract

The sky-radiometer-based observation network called SKYNET is briefly introduced. Two dedicated on-site calibration methods, the improved Langley (IL) and solar disk scan (SDS) methods, enable long-term continuous well-calibrated observation of the optical properties of atmospheric aerosols. The uncertainty in the calibration constant derived using the IL method was estimated to be better than 2.4%. The uncertainty in the solid view angle estimated using the SDS method was improved and found from simulation to be lower than 0.5% under low aerosol conditions. To confirm these estimates, aerosol optical depth (or aerosol optical thickness) comparisons with other independent data generally showed a root-mean-square difference smaller than ~0.02 at a wavelength (λ) ≥500 nm and ~0.03 at shorter wavelengths. The accuracy of the single scattering albedo retrieval was found to be better than ~0.02 for λ ≤500 nm and tended to take a larger value of ~0.05 at 870 nm. Recent progress supporting the ability of SKYNET to enable precise quantitative analysis of light-absorbing aerosols is also presented. Efforts to improve the retrieval methods for aerosols and other components, such as clouds, water vapor, and ozone, are ongoing together with growth of the international SKYNET community.

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Author information

Authors and Affiliations

  1. Center for Environmental Remote Sensing, Chiba University, Chiba, Japan

    Hitoshi Irie

  2. The University of Tokyo, Kashiwa, Chiba, Japan

    Teruyuki Nakajima

Authors
  1. Hitoshi Irie
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  2. Teruyuki Nakajima
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Correspondence to Hitoshi Irie .

Editor information

Editors and Affiliations

  1. National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan

    Hajime Akimoto

  2. National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan

    Hiroshi Tanimoto

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Irie, H., Nakajima, T. (2023). SKYNET. In: Akimoto, H., Tanimoto, H. (eds) Handbook of Air Quality and Climate Change. Springer, Singapore. https://doi.org/10.1007/978-981-15-2760-9_52

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