Publication Date:
2023-01-13
Description:
The 19-channel rotating shadowband radiometer GUVis-3511 built by Biospherical Instruments provides automated shipborne measurements of the direct, diffuse and global spectral irradiance components without a requirement for platform stabilization. Several direct sun products, including spectral direct beam transmittance, aerosol optical depth, Ångström exponent and precipitable water, can be derived from these observations. The individual steps of the data analysis are described, and the different sources of uncertainty are discussed. The total uncertainty of the observed direct beam transmittances is estimated to be about 4 % for most channels within a 95 % confidence interval for shipborne operation. The calibration is identified as the dominating contribution to the total uncertainty. A comparison of direct beam transmittance with those obtained from a Cimel sunphotometer at a land site and a manually operated Microtops II sunphotometer on a ship is presented. Measurements deviate by less than 3 and 4 % on land and on ship, respectively, for most channels and in agreement with our previous uncertainty estimate. These numbers demonstrate that the instrument is well suited for shipborne operation, and the applied methods for motion correction work accurately. Based on spectral direct beam transmittance, aerosol optical depth can be retrieved with an uncertainty of 0.02 for all channels within a 95 % confidence interval. The different methods to account for Rayleigh scattering and gas absorption in our scheme and in the Aerosol Robotic Network processing for Cimel sunphotometers lead to minor deviations. Relying on the cross calibration of the 940 nm water vapor channel with the Cimel sunphotometer, the column amount of precipitable water can be estimated with an uncertainty of ± 0.034 cm.
Keywords:
Aerosol optical thickness at 1020 nm; Aerosol optical thickness at 1245 nm; Aerosol optical thickness at 1550 nm; Aerosol optical thickness at 1640 nm; Aerosol optical thickness at 340 nm; Aerosol optical thickness at 380 nm; Aerosol optical thickness at 412 nm; Aerosol optical thickness at 443 nm; Aerosol optical thickness at 510 nm; Aerosol optical thickness at 610 nm; Aerosol optical thickness at 625 nm; Aerosol optical thickness at 665 nm; Aerosol optical thickness at 694 nm; Aerosol optical thickness at 750 nm; Aerosol optical thickness at 765 nm; Aerosol optical thickness at 875 nm; Aerosol optical thickness at 940 nm; ALTITUDE; ANT-XXIX/10; Atlantic, transit cruise; CT; DATE/TIME; Diffuse radiation; Direct radiation; Ground-Based UV-Visble radiometer with BioSHADE accessory, GUVis-3511, BSI Inc.; LATITUDE; LONGITUDE; Polarstern; PS83; PS83-track; Short-wave downward (GLOBAL) radiation; Spectral irradiance, downward at 1020 nm; Spectral irradiance, downward at 1245 nm; Spectral irradiance, downward at 1550 nm; Spectral irradiance, downward at 1640 nm; Spectral irradiance, downward at 305 nm; Spectral irradiance, downward at 340 nm; Spectral irradiance, downward at 380 nm; Spectral irradiance, downward at 412 nm; Spectral irradiance, downward at 443 nm; Spectral irradiance, downward at 510 nm; Spectral irradiance, downward at 610 nm; Spectral irradiance, downward at 625 nm; Spectral irradiance, downward at 665 nm; Spectral irradiance, downward at 694 nm; Spectral irradiance, downward at 750 nm; Spectral irradiance, downward at 765 nm; Spectral irradiance, downward at 875 nm; Spectral irradiance, downward at 940 nm; Spectral irradiance, downward - incident at 1020 nm; Spectral irradiance, downward - incident at 1245 nm; Spectral irradiance, downward - incident at 1550 nm; Spectral irradiance, downward - incident at 1640 nm; Spectral irradiance, downward - incident at 305 nm; Spectral irradiance, downward - incident at 340 nm; Spectral irradiance, downward - incident at 380 nm; Spectral irradiance, downward - incident at 412 nm; Spectral irradiance, downward - incident at 443 nm; Spectral irradiance, downward - incident at 510 nm; Spectral irradiance, downward - incident at 610 nm; Spectral irradiance, downward - incident at 625 nm; Spectral irradiance, downward - incident at 665 nm; Spectral irradiance, downward - incident at 694 nm; Spectral irradiance, downward - incident at 750 nm; Spectral irradiance, downward - incident at 765 nm; Spectral irradiance, downward - incident at 875 nm; Spectral irradiance, downward - incident at 940 nm; Spectral irradiance, incident at 1020 nm; Spectral irradiance, incident at 1245 nm; Spectral irradiance, incident at 1550 nm; Spectral irradiance, incident at 1640 nm; Spectral irradiance, incident at 305 nm; Spectral irradiance, incident at 340 nm; Spectral irradiance, incident at 380 nm; Spectral irradiance, incident at 412 nm; Spectral irradiance, incident at 443 nm; Spectral irradiance, incident at 510 nm; Spectral irradiance, incident at 610 nm; Spectral irradiance, incident at 625 nm; Spectral irradiance, incident at 665 nm; Spectral irradiance, incident at 694 nm; Spectral irradiance, incident at 750 nm; Spectral irradiance, incident at 765 nm; Spectral irradiance, incident at 875 nm; Spectral irradiance, incident at 940 nm; Underway cruise track measurements
Type:
Dataset
Format:
text/tab-separated-values, 444304 data points
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