Estimating the thickness of ridged sea ice from ship observations in the Ross Sea

T Tin*, MO Jeffries, M Lensu, J Tuhkuri

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)


Ship-based observations of sea ice thickness using the Antarctic Sea Ice Processes and Climate (ASPeCt) protocol provide information on ice thickness distribution at relatively low cost. This protocol uses a simple formula to calculate the mass of ice in ridges based on surface observations. We present two new formulae and compare these with results from the "Original" formula using data obtained in the Ross Sea in autumn and winter, The new "r-star" formula uses a more realistic ratio of sail and keel areas to transform dimensions of sails to estimates of mean keel areas. As a result, estimates of "equivalent thickness" (i.e. mean thickness of ice in ridged areas) increased by over 200%. The new "Probability" formula goes one step further, by incorporating the probability that a sail is associated with a keel underwater, and the probability that keels may be found under level surfaces. This resulted in estimates of equivalent thickness comparable with the Original formula. Estimates of equivalent thickness at one or two degree latitude resolution are sufficiently accurate for validating sea ice models. Although ridges are small features in the Ross Sea, we have shown that they constitute a significant fraction of the total ice mass.

Original languageEnglish
Pages (from-to)47-54
Number of pages8
JournalAntarctic Science
Issue number1
Publication statusPublished - Jan 2003
MoE publication typeA1 Journal article-refereed
EventInternational Conference on the Oceanography of the Ross Sea - Antarctica - Ischia, Italy
Duration: 8 Oct 200113 Oct 2001
Conference number: 2


  • Antarctica
  • ASPeCt
  • pressure ridges
  • sea ice thickness distribution


Dive into the research topics of 'Estimating the thickness of ridged sea ice from ship observations in the Ross Sea'. Together they form a unique fingerprint.

Cite this