Scavenging of atmospheric ions and aerosols by the drifting snow at Antarctica
Measurements of the small-, intermediate-, and large-ion concentrations and the air-earth urrent density along with simultaneous measurements of the concentration and size-distribution of aerosol particles in the size-ranges of 4.4 - 163 nm and 0.5 - 20 μm diameters are reported for a drifting-snow period after the occurrence of a blizzard at a coastal station, Maitri, Antarctica. Observations show a simultaneous decrease in ion concentrations of all categories by approximately an order of magnitude as the wind speed increases from 5 to 12 ms -1 . The rate of decrease is the highest for large ions, the lowest for small ions and in between the two for intermediate ions. The air-earth current also undergoes a decrease during this period. Total aerosol number concentration decreases in the 4.4 – 163 nm size-range but increases in 0.5 – 20 μ m size range with wind speed. Size distribution of the nanometer particles show a dominant maxima at ~ 30 nm diameter throughout the period of observations and the height of maxima decreases with wind speed. When solar radiation is plenty, another maxima appears at ~11 nm and the size distributions show presence of particles as small as 4.6 nm in diameter. On the other hand, larger particles show a maxima at 0.7 μm diameter but the height of maxima increases with increasing wind speed. The results are explained in terms of scavenging of atmospheric ions and aerosols by the drifting snow particles. Formation of new particles by the gas-to-particle conversion processes is proposed to explain the size distribution of nano-size particles.
A K Kamra Devendraa Siingh Vimlesh Pant
Indian Institute of Tropical Meteorology, Pune 411 008, India
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）