Other Scholarly Content

 

Observations of ice nuclei and heterogeneous freezing in a Western Pacific extratropical storm Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/defaults/q811km226

Descriptions

Attribute NameValues
Creator
Abstract
  • In situ airborne sampling of refractory black carbon (rBC) particles and Ice Nuclei (IN) was conducted in and near an extratropical cyclonic storm in the western Pacific Ocean during the Pacific Dust Experiment, PACDEX, in the spring of 2007. Airmass origins were from Eastern Asia. Clouds associated primarily with the warm sector of the storm were sampled at various locations and altitudes. Cloud hydrometeors were evaporated by a counterflow virtual impactor (CVI) and the residuals were sampled by a single particle soot photometer (SP2) instrument, a continuous flow diffusion chamber ice nucleus detector (CFDC) and collected for electron microscope analysis. In clouds containing large ice particles, multiple residual particles were observed downstream of the CVI for each ice particle sampled on average. The fraction of rBC compared to total particles in the residual particles increased with decreasing condensed water content, while the fraction of IN compared to total particles did not, suggesting that the scavenging process for rBC is different than for IN. In the warm sector storm midlevels at temperatures where heterogeneous freezing is expected to be significant (here −24 to −29 °C), IN concentrations from ice particle residuals generally agreed with simultaneous measurements of total ice concentrations or were higher in regions where aggregates of crystals were found, suggesting heterogeneous freezing as the dominant ice formation process in the mid levels of these warm sector clouds. Lower in the storm, at warmer temperatures, ice concentrations were affected by aggregation and were somewhat less than measured IN concentrations at colder temperatures. The results are consistent with ice particles forming at storm mid-levels by heterogeneous freezing on IN, followed by aggregation and sedimentation to lower altitudes. Compositional analysis of the aerosol and back trajectories of the air in the warm sector suggested a possible biomass burning source for much of the aerosol. Comparison of the particles from the CFDC with the other aerosol in the residuals of ice particles suggested that the largest portion of IN had similar inferred origins (from biomass burning with minor amounts of rBC) as the other aerosol, but contained slightly elevated amounts of calcium and less influence from sea salt.
Resource Type
DOI
Date Available
Date Issued
Citation
  • Stith, J. L., Twohy, C. H., DeMott, P. J., Baumgardner, D., Campos, T., Gao, R., and Anderson, J.: Observations of ice nuclei and heterogeneous freezing in a Western Pacific extratropical storm, Atmospheric Chemistry and Physics, 11, 6229-6243, doi:10.5194/acp-11-6229-2011, 2011.
Series
Rights Statement
Funding Statement (additional comments about funding)
  • The National Center for Atmospheric Research is supported by the National Science Foundation. This work was also supported by NSF Grants ATM-0611936 (DeMott), ATM-0612605 (Baumgardner), ATM-0612605 (Twohy), and ATM-076671 (Anderson). Additional support was provided by NASA grant NNX08AH57G (Twohy).
Publisher
Language
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2012-06-18T21:58:17Z (GMT). No. of bitstreams: 3 TwohyCHCEOASObservationsIceNuclei.pdf: 2215784 bytes, checksum: b97418699ff1bd36a598c77d8dab8f6f (MD5) license_rdf: 22765 bytes, checksum: 56265f5776a16a05899187d30899c530 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2011-07-01
  • description.provenance : Submitted by Deborah Campbell (deborah.campbell@oregonstate.edu) on 2012-06-18T21:58:17Z No. of bitstreams: 3 TwohyCHCEOASObservationsIceNuclei.pdf: 2215784 bytes, checksum: b97418699ff1bd36a598c77d8dab8f6f (MD5) license_rdf: 22765 bytes, checksum: 56265f5776a16a05899187d30899c530 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)

Relationships

Parents:

This work has no parents.

Items