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Particle number mixing ratios of tropospheric and stratosphenc aerosols were observed in the Arctic Airborne Measurement Program 1998 (AAMP 98) using an Optical Particle Counter onboard a sub-sonic aircraft, the Gulfstream II (G-11) in March 1998. The observational results showed horizon­tally homogeneous distributions of particle number mixing ratio at the cruise altitude (about 12 km). On the other hand, distinct size-number distributions were found at some points on the flight paths, which suggest that effects of the warm conveyor belts appeared eastward of trough of atmospheric pressure. The characteristics of observed particle size-number distributions are discussed with isentropic backward trajectory analyses and geopotential maps.

In order to know the morphology and mixing state of atmospheric aerosol particles in the spring Arctic atmosphere, direct sampling of aerosol particles was carried out using an aerosol impactor system during the Arctic Airborne Measurement Program (AAMP 98). Aerosol samples were observed with a scanning electron microscope and analyzed with an energy-dispersive X-ray spectrometer. Aerosol particles with clear satellite structure due to sulfuric acid droplets were observed in samples collected in the lower stratosphere and free troposphere. On the other hands, aerosol particles with crystal and satellite structure due to droplets of sea salt particles were observed in the boundary layer.

1957年3月から1958年2月までの昭和基地の風向,風速,気温について,毎時の観測値を整理した結果を報告する.(1)風向 最多風向は3, 4,5の各月はNEで,その他の月はNNE,南よりの風(SE-SW)は4,5,9,12,2の各月に多く,静穏は7,8,9の3ヶ月に多い.1年を通じては,全観測回数の約60%はNNE-ENEの風である.(2)風速 風力9以上(20.8m/s以上)は3,7,8の各月に多く,それぞれの月の約6%風力3以下(3.4m/s以下)は8,9,10,12,2の各月に多く,それぞれの月の60%を越す.風速の日変化は,10月から2月までは規則的で,最大は5時前後,最小は20時前後である.(3)気温 1年を通じ,0℃以上は全観測回数の8%,-30℃以下は1%で,0.0-9.9℃が45%を占める.旬平均値によると,低温と弱風速および南よりの風がよく対応している.