1Leibniz Institute for Tropospheric Research, Permoserstr. 15, 04318
2Environmental Chemistry Department, Helmholtz-Zentrum Geesthacht,
Max-Planck-Straße 1, 21502 Geesthacht, Germany
3Division of Nuclear Physics, Lund University, Professorsgatan 1, 22363
4Department of Atmospheric Science, University of Wyoming, 1000 E.
University Avenue, Laramie, WY 82071, USA
5 Air Chemistry Division, Max Planck Institute for Chemistry,
Hahn-Meitner-Weg 1, 55128 Mainz, Germany
6Institute for Meteorology and Climate
Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
anow at: Federal Maritime and Hydrographic Agency, Wuestland 2, 22589 Hamburg,
Received: 11 Sep 2015 – Discussion started: 04 Nov 2015
Abstract. The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new optical particle size spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region on board a passenger aircraft (IAGOS-CARIBIC observatory: In-service Aircraft for a Global Observing System – Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container). A modified KS93 particle sensor from RION Co., Ltd., together with a new airflow system and a dedicated data acquisition system, is the key component of the CARIBIC OPSS. The instrument records individual particle pulse signal curves in the particle size range 130–1110 nm diameter (for a particle refractive index of 1.47-i0.006) together with a time stamp and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instrument's measurement performance shows no pressure dependency and no particle coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of 2 in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.
Revised: 08 Mar 2016 – Accepted: 22 Mar 2016 – Published: 17 May 2016
Hermann, M., Weigelt, A., Assmann, D., Pfeifer, S., Müller, T., Conrath, T., Voigtländer, J., Heintzenberg, J., Wiedensohler, A., Martinsson, B. G., Deshler, T., Brenninkmeijer, C. A. M., and Zahn, A.: An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC, Atmos. Meas. Tech., 9, 2179-2194, doi:10.5194/amt-9-2179-2016, 2016.