Estimation of aerosol size distribution from ion mobility spectra using the KL model

Abstract

Atmospheric ion mobility spectra were measured at Maitri, Antarctica, using an indigenously fabricated ion mobility spectrometer in January–February 2005 during the 24th Indian Antarctic Expedition. The ion mobility spectrometer was fabricated and tested at the Indian Institute of Tropical Meteorology, Pune, India. As the ion mobility depends on the diameter of the particles, the aerosol size distribution was derived from the observed ion mobility spectra using the KL model. The model was tested by comparing the derived spectra with the observed spectra using the Scanning Mobility Particle Sizer and the Aerodynamic Particle Sizer. We show that the KL model can reasonably reproduce the observed size distribution except in the accumulation mode. Relevant meteorological parameters are also reported, which aid in the interpretation of the results.

Acknowledgements

Devendraa Siingh (D.S.) thanks the National Centre for Antarctic and Ocean Research (NCAOR), Goa, India, for participation in the 24th Indian Scientific Expedition to Antarctica (ISEA) and the India Meteorological Department for providing the meteorological data. Dr A. K. Kamra is thanked for full support during the expedition and fabrication of the instrument. He also thanks V. Pant (RS) for observational support. He thanks the anonymous reviewers for their critical comments, which helped to improve the scientific value of this article. Part of the work for this article was completed when D.S. was at the Institute of Physics, University of Tartu, Estonia, during his deputation under the BOYSCAST fellowship programme (with reference SR/1313BY/A-19/05), DST, Government of India. D.S. expresses his gratitude to Prof. H. Tammet and Urmas Horrak, Institute of Physics, University of Tartu, Estonia, for the model and valuable discussions. Prof. B. N. Goswami, Director, IITM, Pune, is thanked for his encouragement and support.