Articles | Volume 9, issue 10
https://doi.org/10.5194/amt-9-5183-2016
https://doi.org/10.5194/amt-9-5183-2016
Research article
 | 
24 Oct 2016
Research article |  | 24 Oct 2016

A broad supersaturation scanning (BS2) approach for rapid measurement of aerosol particle hygroscopicity and cloud condensation nuclei activity

Hang Su, Yafang Cheng, Nan Ma, Zhibin Wang, Xiaoxiang Wang, Mira L. Pöhlker, Björn Nillius, Alfred Wiedensohler, and Ulrich Pöschl

Abstract. The activation and hygroscopicity of cloud condensation nuclei (CCN) are key to the understanding of aerosol–cloud interactions and their impact on climate. They can be measured by scanning the particle size and supersaturation in CCN measurements. The scanning of supersaturation is often time-consuming and limits the temporal resolution and performance of CCN measurements. Here we present a new approach, termed the broad supersaturation scanning (BS2) method, in which a range of supersaturation is simultaneously scanned, reducing the time interval between different supersaturation scans. The practical applicability of the BS2 approach is demonstrated with nano-CCN measurements of laboratory-generated aerosol particles. Model simulations show that the BS2 approach may also be applicable for measuring CCN activation of ambient mixed particles. Due to its fast response and technical simplicity, the BS2 approach may be well suited for aircraft and long-term measurements. Since hygroscopicity is closely related to the fraction of organics/inorganics in aerosol particles, a BS2-CCN counter can also serve as a complementary sensor for fast detection/estimation of aerosol chemical compositions.

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Short summary
In cloud condensation nuclei (CCN) measurements, the supersaturation scan is often time-consuming and limits the temporal resolution of CCN measurements. Here we present a new concept, termed the broad supersaturation scanning (BS2) method, in which a range of supersaturation is simultaneously scanned, resulting in fast measurements of CCN activity.