GIANT PARTICLES IN THE LOWER STRATOSPHERE

概要

Polar stratospheric clouds (PSCs) are well known phenomena in the lower polar stratosphere. Using the data of balloon flights at McMurdo Station, Antarctica, D. J. HOFMANN et al. (J. Geophys. Res., 93,665,1988) and D. J. HOFMANN (Nature, 337,447,1989) have recently showed vertical profiles of aerosol above the altitude of 10km. The upper limit of the particle size of their measurements was less than about 1μm. We present here the results of balloon observations for measuring relatively large particles (more than 10μm) in the lower stratosphere. The sounding instrument of particles was similar in design to that described by M. MURAKAMI et al. (J. Meteorol. Soc. Jpn., 65,803,1987) called Cloud Particle Video Sonde (CPVS), whose main device was a TV camera. Four balloon flights for sounding stratospheric particles were carried out on May 28,August 5,August 20 and September 2 in 1988 at Syowa Station (69°S, 40°E), Antarctica. Giant particles which look like liquid particles were found on pictures transmitted from the TV camera ascending with the balloon. The size of the largest one was about 150μm diameter. Particles of more than 100μm diameter were found every flight in the lower stratosphere. There is a possibility that the film does not show liquid particles, but non-uniformity of the surface of the film itself, because CPVS uses water-repellent film for collecting particles and the coating was probably not uniform on the film surface. An attempt to check this point is being carried out.

著者

Wada Makoto National Institute For Polar Research

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