Size and Number Concentration of Liquid PSCs

Abstract

Size (radius: 0.15-1.8 um) and number concentration of polar stratospheric clouds (PSCs) were observed with a balloon-borne particle counter at Ny-Alesund, Norway (79N, 12E) in winter of 1994/95 (December 18, 1994 and January 17, 1995. The measurements suggested that PSCs actively formed in the cold winter stratosphere. During the balloon-borne measurements, the depolarization ratio of PSCs was monitored with a lidar near the balloon observational site to see the phase (liquid or solid) of PSCs. Both measurements suggested that many sub-layers were contained in the PSCs.Particle size distribution of the early PSCs event (December 18, 1994) was different from that observed on January 17, 1995, after active PSCs events. This difference possibly suggests that particle formation processes were largely disturbed by redistribution of chemical constituents relating with PSCs formation and growth in the polar winter stratosphere. Lidar measurements suggested active formation of liquid phase PSCs in addition to solid phase PSCs. The number-size distribution pattern showed enhancement of the number of particles with their radius larger than 1.8, am in the solid state sub-layer of PSCs. On the other hand, not only large particles (r > 1.8 um) but also smaller particles (r=0.25-0.6um) were enhanced in the liquid state PSCs.

Dust particles in free troposphere over Chinese desert region revealed from balloon borne measurements under calm weather conditions

“…A balloon train was used to measure the aerosol number concentration and size on 17 August 2001, 17 October 2001, 11 January 2002, and 30 April 2002 with an Optical Particle Counter (OPC) over the free troposphere under calm weather conditions at Dunhuang. This balloon-borne particle counter used in sampling has been described in many studies (Hayashi et al 1998). The main specifications of the balloon-borne particle counter are described in Table S1.…”

In situ measurements and backward-trajectory analysis of high-concentration, fine-mode aerosols in the UTLS over the Tibetan Plateau

“…Given its high-altitude, unique geographical location, and consequently great challenge and high expense, in situ observations of aerosols at the TP are quite important and scarce, except, to the best of our knowledge, the following two studies. First, Tobo et al (2007) used a balloon-borne optical particle counter (OPC) (Hayashi et al 1998) to measure the vertical profile of aerosols in Lhasa, China (29.4°N, 91.1°E; 3650 m ASL, as shown in figure 1), in 1999. They detected relatively high number concentrations (0.7-0.8 cm −3 ) of submicron-sized aerosols (0.3-1.2 μm in diameter) present near the tropopause region and inside the ASM region and were suggested to be induced by the deep convection over the TP.…”