Eskimo Prehistory, by Hans-Georg Bandi

In the first part, elaborated upon in an appendix, the different energy budget components are briefly discussed for the North Polar Ocean and the southern pack ice belt, separately for an assumed full ice cover and for the same areas ice free. In addition, the same budget components are discussed for Antarctica. These discussions of the budget forms are not based on new calculations but on the results from other publications which the author chose as the most likely ones. The author rightly points out frequently that the observational basis for the energy budget calculations leaves much to be desired and accordingly the results are highly tentative, especially over the southern pack ice belt. A further source of error, inherent in the author’s approach is, that different authors used different assumptions with the consequence that their results might not be compatible. This becomes especially evident when, as in Fig, A9, the solar radiation absorbed in the atmosphere is obtained as a residual. In this instance the values seem substantially too high. The implication of this might be that, for instance, the minimum in radiation loss for the atmosphere in summer is not present. Similar doubtful points are apparent at some other places. This however, does not detract from the merit of such ompilation of comparative energy budgets. The author discusses then the implication of advances or delays in the break up period and shows convincingly, its profound effect on the energy budget even with moderate assumptions about the albedo. For the Arctic ocean the theory is developed that higher cyclonic activity, coupled with warm air advection, advances the break up period. The second part of the paper concentrates on the relation between pack ice extent and general circulation, and their long and short term fluctuations. For the southern hemisphere a clear seasonal relation between atmospheric heat loss obtained from the energy budget calculations and the zonal wind gradient is established. Further calculations with the different energy budgets give interesting numerical values of the changes in atmospheric heat loss with different annual marches of the pack ice extent. The final result given by the author is that a later melting of the pack ice increases the atmospheric cooling in winter, and hence should increase the zonal circulations. Using the empirical results by Lamb that stronger southern hemisphere circulation leads to a northward displacement of all circulation belts in both hemispheres, the author tries to explain with long term records of ice extent in the Orcadas and temperatures at far northern and southern stations firstly the interrelation between ice cover and general circulation intensity in the south, and then opposite temperature curves in the north and south. Some of the comparisons given by the author are strikingly good, others rather poor, for instance, if a correlation coefficient of 0.17 is quoted for the relation between ice extent in the Orcadas and a southem hemisphere general circulation index. In many places in the paper the author points out, that a verification of the hypotheses put forward can only be obtained, once the computer models are further developed to make best calculations in the indicated directions. To s u m up, this type of constructive summarising paper, which is only too rare in present literature, is a valuable contribution. The only general criticism might be that too little is said as to why the author chose the one reference paper in preference to another, which would have given the reader more insight into the uncertainties and diversities of opinion in this field. But this is a minor shortcoming and every student of energy budget and climatic change will have to read this paper and will read it with pleasure. E. Vowinckel