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Outline challenge of measuring CN description of new “gap” instrument

Performance of a New Low-Pressure Water-Based CN Instrument - Rogers, Hering, Stolzenburg, Oberreit, Quant -. Outline challenge of measuring CN description of new “gap” instrument evolution during ProgSci & T-REX examples of data. June 2006. why measure Condensation Nuclei ?.

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Outline challenge of measuring CN description of new “gap” instrument

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  1. Performance of a New Low-Pressure Water-Based CN Instrument- Rogers, Hering, Stolzenburg, Oberreit, Quant - • Outline • challenge of measuring CN • description of new “gap” instrument • evolution during ProgSci & T-REX • examples of data June 2006

  2. why measure Condensation Nuclei ? • characterize the air: • clean background or pollution • identify aerosol plumes • air mass tracer • identify regions of new particle formation • estimate particle scavenging rates by clouds

  3. challenge of measuring CN • how to cover entire altitude range of HIAPER ? • CN instruments • common; several commercial vendors • particles grow in supersaturated butyl alcohol vapor  few µm  counted with OPC • lose sensitivity at low pressure (alt > ~10 km) threshold detection size changes with pressure • butanol is toxic and flammable • other special-purpose instruments use fluorinert • water as active fluid ?

  4. vapor pressure of water design range

  5. based on TSI-3786aka Aerosol Dynamics / Quant Low-Pressure microprocessor, ethernet, USB, serial 300 ccm, 10 Hz d* ~ 5 nm

  6. flow diagram growth 45°C two pumps, speed control uses feedback from orifice Δp saturate 5°C

  7. WCN evolution during ProgSci  T-REX

  8. RF04 – poor flow control set point 300

  9. rf09 – good flow control

  10. next ? • compile performance history  web site • modifications to firmware  faster water injection rate • delivery of instrument #1 + training • compare CN measurements MASS, FCAS, RDMA • conference paper - International Aerosol Conf., 13G16 • Airborne tests of a new low-pressure water-based CN instrument • http://www.aaar.org/meetings/IAC2006/index.htm

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