LOGIN TO YOUR ACCOUNT

Username
Password
Remember Me
Or use your Academic/Social account:

CREATE AN ACCOUNT

Or use your Academic/Social account:

Congratulations!

You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.

Important!

Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message

CREATE AN ACCOUNT

Name:
Username:
Password:
Verify Password:
E-mail:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Bigg, E. K. (2011)
Publisher: Tellus B
Journal: Tellus B
Languages: English
Types: Article
Subjects:
Concentrations of ice forming nuclei detected by the membrane filter technique were measured at temperatures of − 12.5, − 15 and − 17.5 °C during a voyage on the icebreaker Oden to the North Pole between 1 August and 6 October 1991. Geometric mean concentrations ranged from 13 m−3 at − 15 °C during the first 17 days of the expedition to 2.9 m−3 on the last 17 days of the voyage in good agreement with surface measurements made earlier north of latitude 70°N. On average, concentrations increased by a factor of 4.5 for a 5 °C fall in temperature, less than is common in continental regions. Although air trajectory analysis showed that land sources occasionally influenced concentrations strongly, the time since the air had been over the open ocean was clearly the most important determining factor other than the seasonal decline. This implies an oceanic origin of the nuclei, the relationship being consistent with a halflife of 48.5 h (e-folding time of 70 h), about 60% longer than that of condensation nuclei. An apparent decrease in ice nucleus concentrations with temperature was mainly due to the seasonal change in concentrations but partly to the air trajectories associated with low temperatures. Elapsed time since the air was above the planetary boundary layer or over land also influenced concentrations, suggesting that the upper troposphere was deficient in ice nuclei while land was a weak source. Changes in the mixed depth of the atmosphere appeared to affect ice nucleus concentrations in the same way as condensation nucleus concentrations although poor time resolution limited this to two good examples. North of latitude 80°N, a few ice crystals were present near the surface for a considerable proportion of the total time. Single stellar crystals constituted about 80% of the total, implying growth near − 15 °C in predominantly supercooled clouds. Their concentrations were usually but not always consistent with surface ice nucleus concentrations.DOI: 10.1034/j.1600-0889.1996.t01-1-00007.x
  • No references.
  • No related research data.
  • No similar publications.

Share - Bookmark

Cite this article

Collected from