REGIONAL COMPARATIVE STUDIES ON MICROPARTICLES IN POLAR ICE CORES

• Main Authors: ヒガシ アキラ, ササキ ケンジ, ヤノ ハジメ, オハラ マナミ, Akira HIGASHI, Kenji SASAKI, Hajime YANO, Manami OHARA
• Format: Report
• Language: English
• Published: ABSTRACT 1992
• Subjects: Greenland; Mizuho; Queen Maud Land; Mizuho Station; Antarc*; Antarctica; Polar meteorology and glaciology; Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3758; http://id.nii.ac.jp/1291/00003758/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3758&item_no=1&attribute_id=18&file_no=1

SEM observations have been carried out since 1987 with microparticales contained in medium and shallow depth ice cores retrieved at Mizuho Station (1984 : 70°42'S, 44°20'E, 2230m) and at the Advance Camp (1985,74°12'S, 34°59'E, 3200m) in East Queen Maud Land, Antarctica. Results of observations including morphological classification of particles have been published (HIGASHI et al. : Bull. Galcier Res., 8,31,1990). Addition of observational data from cores of shallow depth at Mizuho, and Asuka Stations (1989 : 71°34'S, 24°08'E, 930m) in Antarctica, and also at Site J in Greenland (1989 : 66°52'N, 46°16'W, 2030m) enabled us to compare regionally the characters of microparticles. The number of particles larger than 0.6μm is on the order of 500 per 0.05ml of melt water (the same unit in the following) for Mizuho cores (depth, 0-400m) and of 1500 for depth shallower than 80m at the Advance Camp, whereas it is of 500 for deeper depth between 100-200m. It is also on the order of 500 for the 200m core at Site J, but if we consider the much larger accumulation rate in south central Greenland than in interior Antarctica, the fall rate of microparticles at Site J must be 5 times larger than in the Mizuho area. For Asuka core, we can also evaluate the larger fall rate, some 8 times that at Mizuho. Many pollen particles were observed in surface snow near Asuka, a new finding in Antarctica. Morphology and results of Energy Dispersive Spectral elementary analysis data for microparticles in ice cores were compared with those of stratospheric microparticles cata-logued in NASA Cosmic Dust Catalogues. In average, the elemental ratio of the particles in the cores resembled that of non-cosmic particles in the stratosphere, but it was difficult to identify origins of individual particles. A full account of results will be published after collecting data from deeper depth cores (400-700m) of Mizuho, which is now in progress.