Abundance of fluorescent biological aerosol particles at temperatures conducive 
to the formation of mixed-phase and cirrus clouds

Twohy, Cynthia H.; McMeeking, Gavin R.; DeMott, Paul J.; McCluskey, Christina S.; Hill, Thomas C. J.; Burrows, Susannah M.; Kulkarni, Gourihar R.; Tanarhte, M.; Kafle, Durga N.; Toohey, Darin W.

doi:10.5194/acp-2016-112

Item

ITEM ACTIONSEXPORT

Add to Basket

Release HistoryDetailsSummary

Released

Paper

Abundance of fluorescent biological aerosol particles at temperatures conducive to the formation of mixed-phase and cirrus clouds

MPS-Authors

/persons/resource/persons101301

Tanarhte, M.
Atmospheric Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Twohy, C. H., McMeeking, G. R., DeMott, P. J., McCluskey, C. S., Hill, T. C. J., Burrows, S. M., et al. (2016). Abundance of fluorescent biological aerosol particles at temperatures conducive to the formation of mixed-phase and cirrus clouds. Atmospheric Chemistry and Physics Discussions, 16.

Cite as: https://hdl.handle.net/11858/00-001M-0000-002C-8FCB-A

Abstract

Some types of biological particles are known to nucleate ice at warmer temperatures than mineral dust, with the potential to influence cloud microphysical properties and climate. However, the prevalence of these particle types above the atmospheric boundary layer is not well known. Many types of biological particles fluoresce when exposed to ultraviolet light, and the Wideband Integrated Bioaerosol Sensor takes advantage of this characteristic to perform real-time measurements of fluorescent biological aerosol particles (FBAPs). This instrument was flown on the National Center for Atmospheric Research Gulfstream V aircraft to measure concentrations of fluorescent biological particles from different potential sources and at various altitudes over the US western plains in early autumn. Clear-air number concentrations of FBAPs between 0.8 and 12 mu m diameter usually decreased with height and generally were about 10-100 L-1 in the continental boundary layer but always much lower at temperatures colder than 255K in the free troposphere. At intermediate temperatures where biological ice-nucleating particles may influence mixed-phase cloud formation (255K <= T <= 270 K), concentrations of fluorescent particles were the most variable and were occasionally near boundary-layer concentrations. Predicted vertical distributions of ice-nucleating particle concentrations based on FBAP measurements in this temperature regime sometimes reached typical concentrations of primary ice in clouds but were often much lower. If convection was assumed to lift boundary-layer FBAPs without losses to the free troposphere, better agreement between predicted ice-nucleating particle concentrations and typical ice crystal concentrations was achieved. Ice-nucleating particle concentrations were also measured during one flight and showed a decrease with height, and concentrations were consistent with a relationship to FBAPs established previously at the forested surface site below. The vertical distributions of FBAPs measured on five flights were also compared with those for bacteria, fungal spores, and pollen predicted from the EMAC global chemistry-climate model for the same geographic region.