open access

https://hdl.handle.net/2115/59590

Natural supersaturation conditions needed for nucleation of air-clathrate hydrates in deep ice sheets

英語

ice core

2015-02-04

International Glaciological Society

Journal of glaciology

60(224)

1111-1116

We apply new phase-equilibrium data of air-clathrate hydrates to the distribution of air hydrates in deep ice sheets to better understand their nucleation conditions. By comparing the depths at which the hydrates first appear to the phase-equilibrium condition, we estimated the critical size of an air-hydrate nucleus in an ice sheet to be similar to 50 nm. The estimated energy barrier for nucleation, based on the temperature dependence of supersaturation, is much smaller than that estimated previously for the pure ice system. Thus, the bubble surface may either act as a type of heterogeneous nucleus, or contain heterogeneous nuclei, for hydrate formation. Competition between nucleation-promotion and nucleation-inhibition factors may increase variation in nucleation rates, resulting in variation of the depth range of the bubble hydrate transition zones.

学術雑誌論文

Version of Record

© 2015 International Glaciological Society

0022-1430