A constructive step forward has been made in the still thorny field of sea ice terminology with the publication by the Scott Polar Research Institute of this excellent illustrated glossary. An abstract of a more complete glossary which will he published later; it is intended as a practical aid to mariners navigating in ice and aims to cover the minimum number of terms required. Sixty-eight well chosen terms, of which forty are illustrated, give the seaman and the air observer all they require and save the difficulty of sifting through a lot of technical terms that they will never need.
In the definitions and choice of terms the authors have taken careful consideration of international usage, and especially of usage in English-speaking countries, and they have approached encouragingly near to producing something that is acceptable to all. It should not be difficult to arrive at a satisfactory compromise on the few remaining points of difference with United States terminology, and it is hoped that the forthcoming Canadian glossary, which will be a slight modification of the present work, may be in a position to embody such a compromise.
There remain one or two uncomfortable terms, the most outstanding of which is probably “ice cluster”. This term was originated by the authors to describe a phenomenon noted in recent years by the Russians, who have observed that in the coastal seas of Siberia there are certain areas of ice concentration which persist every year and which they call “massifs”. This apparently simple concept is extremely difficult to express in English without resorting to such words as “field”, which is to be avoided as having other and more general connotations. The word “cluster”, however, at least to this reviewer, is associated with small bunches, as of grapes, and is not really descriptive of the phenomenon. Another term of doubtful value is “bay ice”, which is defined as
“Fast ice of more than one winter’s growth, which may be nourished also by surface layers of snow. Thickness of ice and snow up to about 2m. above sea-level. When bay icc becomes thicker than this it is called an ice shelf.”
This is an Antarctic phenomenon for which some term is essential, hut there seem to be three grave objections to this particular term: in the first place a simple descriptive phrase is being misused, as the incipient shelf need not be, and in fact very commonly is not, in a hay; secondly, the term will inevitably be used as a straightforward descriptive phrase to distinguish between the ice in a bay and in the sea outside, and this is likely to cause confusion; thirdly, by defining it as fast ice of more than one winter’s growth, the authors are by implication restricting the term “fast ice” to one-year-old ice only. In the Arctic this is not acceptable, as there is such a thing as fast ice which is two or more years old but which will never develop beyond a certain thickness owing to low snowfall and the balance of freeze and thaw, and for this “fast ice” remains a perfectly satisfactory term.
The illustrations are first-rate and fully justify the very considerable time and effort which must have been devoted to their selection. Almost without exception they show clearly the feature they are designed to illustrate, a thing not easy to achieve and painfully lacking in most illustrated glossaries. It would have helped however to have an indication of altitude in the case of the few air photographs included, as it is by no means easy to judge the scale. This is particularly true of the ice island photograph, which might be very misleading to those unfamiliar with the subject. By an unfortunate oversight the caption of the illustration of polar ice draws attention to the great thickness of the ice under water, when all that appears in the reproduction is the reflection of the part above the surface.
Concentration of pack ice is expressed in octas, which is in accordance with WMO practice. North American users adhere firmly to tenths, but this is not a serious discrepancy, as the authors have carefully arranged their breakdown so that the terminology and map symbols are interchangeable, and as all estimates of concentration are at best approximate it makes little difference which is used. Measurements are given in the metric system, again, and quite rightly, to conform with international usage. However as the glossary is intended for practical field use by English-speaking mariners, it would have been kind and useful to have included equivalents in feet and miles.
The authors are to be congratulated on an admirable piece of work, and the publication of the longer glossary for scientific use will be eagerly awaited.
