Derivation of atmospheric turbidity at Mizuho Station, Antarctica from the broadband solar radiation measurements

• Main Author: Takashi Yamanouchi
• Format: Report
• Language: English
• Published: National Institute of Polar Research 1982
• Subjects: Mizuho; Mizuho Station; Antarc*; Antarctica; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1324; http://id.nii.ac.jp/1291/00001324/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1324&item_no=1&attribute_id=18&file_no=1

Spectral measurements of the direct solar radiation were made by a pyrheliometer at Mizuho Station, Antarctica in the POLEX-South radiation measuring program. From the broadband measurement using cutoff filters, aerosol optical depths were derived by the Langley method without using a predetermined extraterrestrial solar radiation. Average aerosol optical depths were obtained as 0.020,0.015 and 0.010 for the wavelength region 0-532nm, 532-632nm and 632-693nm respectively. The Ångstrom turbidity coefficient β=0.007,wavelength exponent α=1.4 and optical depth at 500nm _<^τM>(500)=0.017±0.005 were estimated. Comparing with the optical depth measured in Antarctica in the past, present result was in good accordance with the recent measurements made by SHAW using the sun-photometer. Several difficulties in making the results accurate and some disadvantages in broadband measurements are discussed.