A range of miniature, low-cost optical particle counters for characterizing atmospheric particles has been developed. They are intended for use with disposable balloon-borne radiosondes, dropsondes or in dense ground-based sensor networks. Versions exist that are suitable for determining the size distributions and number concentrations of cloud particles or atmospheric aerosols such as mineral dust or volcanic ash.Peer reviewe

Hirst, Edwin

Kaye, Paul H.

Stanley, Warren

Ulanowski, Joseph

Wieser, Andreas

English

University of Hertfordshire Research Archive

Low-cost optical particle counters, Ulanowski 49  The Conference on Optical Characterization of Atmospheric Aerosols Miniature, low-cost optical particle counters Z. Ulanowski1, P. H. Kaye1, E. Hirst1, A. Wieser2, W. R. Stanley1 1 Centre for Atmospheric and Instrumentation Research, University of Hertfordshire, Hatfield AL10 9AB, United Kingdom 2 Karlsruher Institut für Technologie, Institut für Meteorologie und Klimaforschung, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany tel: +44 1707 284604, fax: +44 1707 284185, e-mail: z.ulanowski@herts.ac.uk Abstract A range of miniature, low-cost optical particle counters for characterizing atmospheric particles has been developed. They are intended for use with disposable balloon-borne radiosondes, dropsondes or in dense ground-based sensor networks. Versions exist that are suitable for determining the size distributions and number concentrations of cloud particles or atmospheric aerosols such as mineral dust or volcanic ash. 1 Introduction Routine meteorological data is obtained by profiling the atmosphere using disposable “radiosondes”, thousands of which are launched daily on meteorological balloons. These give temperature, pressure, humidity and wind speed. Additional measurements are obtained from so-called “dropsondes”, released from research aircraft. However, a crucial property not yet measured for lack of suitable equipment is the size and concentration of atmospheric particulates: cloud particles and aerosols. Instead, indirect, measurements are employed, relying on remote sensing, to meet the demands from not only weather forecasting, but many other areas such as climate research, air quality monitoring, civil contingencies etc. In addition, research aircraft can be used in situ, but airborne measurements are expensive. Moreover, aircraft use is restricted to near-horizontal profiling, which is a limitation, as cloud properties are driven by processes taking place in the vertical direction. Therefore, vertical profiling with sondes, either upwards or downwards, is often preferable. There are also many instances when aircraft cannot be used for in situ measurements, ranging from common occurrences, such as vigorous storm systems, to the unusual but far-reaching events, such as volcanic eruptions.  The Centre for Atmospheric and Instrumentation Research at the University of Hertfordshire specializes in the development of light-scattering instruments for the characterization of aerosols and cloud particles. In the last few years a range of miniature particle counters for characterizing atmospheric particles has been developed. They are intended for use together with systems such as disposable balloon-borne radiosondes, aircraft dropsondes or in dense ground-based sensor networks. Versions exist that are suitable for determining the size distributions and number concentrations of particles with different size ranges. They have been used for vertical profiling of atmospheric aerosols such as mineral dust, volcanic ash, as well as clouds, and for ground based air-quality monitoring [5,6]. 2 Selected results An early counter was developed in 2009 for profiling atmospheric mineral dust. It was designed for attaching to a standard Vaisala RS92 radiosonde and launching on a small meteorological balloon. It provided a size distribution in five bins and could also be interfaced to an electric charge sensor to detect aerosol charging [1-3]. In 2010 this counter was used to profile ash layers from the Eyjafjallajökull eruption [4]. A number of these units are currently held by the UK Met Office for use in the event of further volcanic ash episodes. 50 Low-cost optical particle counters, Ulanowski  November 5 –7, 2013, Smolenice, Slovakia A disadvantage of conventional optical particle counters that draw ambient air in through a narrow inlet is that they can become blocked, which is almost inevitable during measurements in the presence of supercooled cloud droplets, for example. Therefore, a different counter version was developed, which can have more open-path geometry, as the sensing zone is defined optically rather than being delimited by the flow system. This counter is currently used in a network of about 50 multi-parameter sensor stations for air quality monitoring around Heathrow airport, and for fog characterization. These counters size particles into bins in the range from 0.35 to 17 µm [5,6]. The counter has now been adapted for use with radiosondes or dropsondes. The dropsonde version has been successfully tested by launching it from research aircraft together with the so-called KITsonde, developed at the Karlsruhe Institute of Technology, which determines standard meteorological parameters and GPS position for transmission back to the aircraft [7]. 3 Conclusion Low cost optical particle counters can be used in conjunction with meteorological radiosondes or dropsondes to obtain vertical profiles of the size distributions and concentrations of atmospheric aerosols and cloud particles on a routine basis. They also allow measurements where research aircraft cannot fly safely, as was demonstrated during the Eyjafjallajökull volcanic eruption. Open-path particle counters are especially valuable, as they permit measurements in the presence of liquid water. Acknowledgments Part of this research and development was carried out with funding from the UK Natural Environment Research Council grants NE/G007268/1 (DREAME) and NE/I007296/1 (SNAQ). References [1] Z. Ulanowski, E Hirst, P H Kaye, R G Harrison, K A Nicoll, and G Rogers  (2010): Radiosonde aerosol counter for vertical profiling of atmospheric dust, Eur. Geophys. Union Gen. Assembly, Vienna. In: Geophys. Res. Abstr. 12, EGU2010-13512.  [2] Z. Ulanowski, I Sabbah, R G Harrison, K A Nicoll, E Hirst, P H Kaye, N Al-Abbadi, and G Rogers (2010): Atmospheric dust charging, vertical profiles and optical properties measured in the Arabian Peninsula during the DREAME campaign, Eur. Geophys. Union Gen. Assembly, Vienna. In: Geophys. Res. Abstr. 12, EGU2010-13473. [3] K.A. Nicoll, R.G. Harrison, Z. Ulanowski (2011): Observations of Saharan dust layer electrification, Env. Res. Lett. 6, 014001. [4] R.G. Harrison, K.A. Nicoll, Z. Ulanowski, and T.A. Mather (2010): Self-charging of the Eyjafjallajökull volcanic ash plume, Env. Res. Lett. 5, 024004. [5] W.R. Stanley, Kaye P.H. and Hirst E. (2013): A low-cost optical particle counter for networked deployment, UK Aerosol Society Annual Conference, Hatfield. [6] M.I. Mead, O. A. Popoola, G. Stewart, V. Bright, P. H. Kaye, and J. Saffell (2012): High-density, high-resolution, low-cost air quality sensor networks for urban air monitoring, AGU - Fall Meeting, San Francisco.  [7] A. Wieser, D. Fütterer, H. Franke, D. Schell, F. Schmidmer, and C. Kottmeier (2009) A novel modular multi-sensor dropsonde system for high resolution measurements. 9th EMS Ann. Meet. Appl. Meteor., Tolouse, EMS2009-396. 

A low-cost optical particle counter for networked deployment,

A novel modular multi-sensor dropsonde system for high resolution measurements. 9th EMS Ann.

Atmospheric dust charging, vertical profiles and optical properties measured

High-density, high-resolution, low-cost air quality sensor networks for urban air monitoring, AGU - Fall Meeting,

Radiosonde aerosol counter for vertical profiling of atmospheric dust,

Self-charging of the Eyjafjallajökull volcanic ash plume,

Ulanowski (2011): Observations of Saharan dust layer electrification,

Miniature, low-cost optical particle counters

Miniature, low-cost optical particle counters

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