Abstract
New calculations of the relative optical air mass function are made over the 0°–87° range of apparent solar zenith angle θ, for various vertical profiles of background aerosol, diamond dust and thin cirrus cloud particle extinction coefficient in the Arctic and Antarctic atmospheres. The calculations were carried out by following the Tomasi and Petkov (2014) procedure, in which the above-mentioned vertical profiles derived from lidar observations were used as weighting functions. Different sets of lidar measurements were examined, recorded using: (i) the Koldewey-Aerosol-Raman Lidar (KARL) system (AWI, Germany) at Ny-Ålesund (Spitsbergen, Svalbard) in January, April, July and October 2013; (ii) the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite-based sensor over Barrow (Alaska), Eureka (Nunavut, Canada) and Sodankylä (northern Finland), and Neumayer III, Mario Zucchelli and Mirny coastal stations in Antarctica in the local summer months of the last two years; (iii) the National Institute of Optics (INO), National Council of Research (CNR) Antarctic lidar at Dome C on the Antarctic Plateau for a typical “diamond dust” case; and (iv) the KARL lidar at Ny-Ålesund and the University of Rome/National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) lidar at Thule (northwestern Greenland) for some cirrus cloud layers in the middle and upper troposphere. The relative optical air mass calculations are compared with those obtained by Tomasi and Petkov (2014) to define the seasonal changes produced by aerosol particles, diamond dust and cirrus clouds. The results indicate that the corresponding air mass functions generally decrease as angle θ increases with rates that are proportional to the increase in the pure aerosol, diamond dust and cirrus cloud particle optical thickness.
Highlights
Regular sun-photometer measurements are currently conducted at numerous Arctic and Antarctic sites to determine the spectral values of aerosol optical thickness τa(λ) at visible and near-infrared wavelengths [1]
Cimel CE-318 of the Aerosol Robotic Network (AERONET) network [2], the Prede POM-01L and POM-02L sun/sky-radiometers of the SKYNET network [3], the hand-held Microtops sun-photometers of the Maritime Aerosol Network (MAN) [4], the EKO MS-110 model [5] used by the Japan Meteorological
Following the criteria established by the multispectral sun-photometry method [18], each measurement of direct solar irradiance J(λ) is examined in terms of the Lambert-Beer law to determine the total optical thickness τ(λ) of the atmosphere in terms of the following analytical form obtained by inverting the well-known Lambert-Beer law:
Summary
Regular sun-photometer measurements are currently conducted at numerous Arctic and Antarctic sites to determine the spectral values of aerosol optical thickness τa(λ) at visible and near-infrared wavelengths [1]. These measurements are conducted using different sun-photometer models such as the. To be accurately known in order to determine the monochromatic value of τ(λ) with the best precision This is important in the polar regions, where the aerosol optical thickness τa(λ) is often very low [6], and aerosol radiative effects may be not negligible [21]. Carter Scott SP01, SP01-A, SP02 and SP022 models of Barrow (Alaska, USA); Alert the GMD/NOAA
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