Report on Norwegian Fishery and Marine-Investigations Vol. 11 1909 No. 2
THE NORWEGIAN SEA
ITS PHYSICAL OCEANOGRAPHY
BASED UPON THE NORWEGIAN
BJØRN HELLAND-HANSEN AND FRIDTJOF NANSEN
(WITH 28 PLATES)
DET MALLINGSKE BOGTRYKKERI
In the present memoir on the Physical Oceanography of the Norwegian Sea we have described the results of the Norwegian investigations made in this sea area, chiefly with the Michael Sars, during the five years of 1900 to 1904. We have also to some extent made use of the observations taken in the southern Norwegian Sea in May, 1905, and the current-measurements made in recent years (1906 & 1908). The other observations taken since 1904, are of less importance for our discussions in the present work, as they were chiefly taken in the coast-waters for other purposes.
The original plan of the work was that Nansen, who organized and led the physical part of the investigations in 1900, should have written a report on the results of the researches of that first year, while Helland-Hansen, who has had charge of the physical investigations since 1900, should have written separate reports on the results of the following years. Nansen  wrote a preliminary account of the researches in 1900, and also began the preparation of his final report ; but owing to other pressing work he was for some time prevented from finishing it. In the mean while a much greater and very important observation-material had been collected during the continued researches of the succeeding years. By these later observations the results of the first year were essentially completed, and were even altered on many important points. Helland-Hansen was much occupied with the continuous investigations and with other work, so that he could not commence his report until 1904.
Under these circumstances we considered it preferable to unite our efforts, and we therefore agreed to work up together the whole observation-material into one memoir, which would give a more complete description of the oceanography of the Norwegian Sea. Other work, and various circumstances, have, however, hindered us from finishing this memoir until now. The different parts of it have been written at various periods since 1902, and it is therefore possible that several recent publications have not been duly considered by us, because our manuscript had been written before they appeared. But wherever it was possible we have tried to add notes referring to later publications of importance. We may also mention that our Plates II-XXIVA were printed in 1905. The final discussion of the observations has since led us to views and conclusions that, as regards several details, made an alteration of some figures in the Plates desirable; but in the text we have called attention to alterations of this kind, which we considered to be important.
Although the report which we now publish may seem voluminous, it is not as detailed on many points as we think that it ought to have been, if time had permitted. There are even several questions of interest, which we have hardly been able to mention, as we had to confine ourselves to the main features.
We hope, however, that we are not too immodest, if we say that the great observation-material at our disposal has led us to a number of discoveries, which are important in several respects, and which give great promise for the future. We may mention the new views on the movements of the water in the sea mentioned in Chapters VI, VII, VIII, IX, and X, the discovery of the formation, distribution, and uniformity of the bottom-water, Chap. XI, etc. But of more general interest are perhaps the annual variations in the currents (the Atlantic Current, Chap. VII, and the Coast Current, Chap. VIII), and their relations to the variations in the climate of Norway, the variations in the fisheries, and also the variations in the harvests of Norway, the growth of the forests, etc. We have also been able to trace a certain relation between these variations and cosmic causes. We think that these discoveries give us the right to hope that by continued investigations it will be possible to predict the character of climate, fisheries, and harvests, months or even years in advance.
There is here a great field for future investigation into which we wish that time would have allowed us to go more fully; but we have been obliged to confine ourselves at present to laying down the main lines and pointing out briefly certain great features, while we have retained the more detailed investigations for special works on the relation between the Hydrosphere and the Atmosphere, and on the relation between oceanic currents and biological conditions, which we hope to publish in a near future.
The observations which we now publish have for the most part been collected during the cruises of the Michael Sars ( The names of those who have taken the observations and collected the water-samples are mentioned in our Tables II and III. ); valuable material has also been collected during the cruises of the Heimdal, of the Royal Norwegian Navy, in May, 1901 and 1902, and the fisherysteamer Ask in November, 1903. A great number of surface-observations have been sent in by captains of sealing-vessels, viz: FR. SVENDSEN (Hvidfisken), INGVALD SVENDSEN (Hvidfsken and Jasai), P . CHR. ISAKSEN (Tora den Blide), and H. ANDRESEN (Rivalen), of Tromsø; CHR. LARSEN (Urania), of Aalesund ; HAUELAND (Egil), of Bergen; J. NILSEN (Aksel, and Kvik), A. MARCUSSEN (Hekla, and Vega), A. STOKKEN (Capella) and A. B. ABRAHAMSEN (Fortuna), of Sandefjord.
In mentioning those who have assisted us in our work we naturally first of all wish to express our gratitude to Dr. JOHAN HJORT, the able leader of the Norwegian Marine and Fishery Researches, who with intelligent interest, has always assisted us in every way, and to whose enterprise and initiative these investigations are due in the first instance.
We also thank Dr. D. DAMAS, Professor Dr. H. H. GRAN, Mr. E. KOEFOED, Mr. A. M.SCHWEIGAARD, and Mr. HERBERT E.W. LEVIN for their valuable assistance in collecting observations during several cruises.
We wish also to tender special thanks to the captains of the ships: Mr. G. SØRENSEN, and Mr. THOR IVERSEN, masters of the Michael Sars, Capt. BURCHHARDT, and Capt. TRYGGVE HOLST, who commanded the Heimdal on the cruises in 1901, and 1902, and Mr. KJÆRSTAD, master of the Ask. By the able way in which they have navigated their ships, and the great interest with which they have furthered the investigations, they have an important share in the results.
Finally we wish to thank the masters of the sealing-vessels, mentioned above, for the valuable assistance they have given us, by collecting observations and water-samples from the Arctic regions, which have been of great importance for our discussion.
We have previously made a great many communications about our investigations and some of their results. Summaries of the investigations have been given for each year in the Annual Report of the Norwegian Fishery Investigations ("Aarsberetning vedkommende Norges fiskerier", published by the Director of the Fisheries, Bergen ). In 1901 Nansen gave a preliminary account of some results of the cruise in 1900. Dr. HJORT  wrote a paper in Petermann's geographische Mitteitungen, and he has also made communications in several papers, and given lectures, e. g. at the meetings of the International Council for the Study of the Sea, in "Institut für Meereskunde" in Berlin etc. Helland-Hansen, every year since 1903, has given lectures at the International Courses on Oceanic Research, in Bergen, where our results have been described; he read a paper before the Hydrographical Congress in Copenhagen in 1904 . He wrote a summary in Dr. HJORT's book "Norsk Havfiske" , and he has made communications about our work at the meetings of the International Council for the Study of the Sea in Amsterdam (1906) and London (1907). Nansen also made communications regarding our results at the meeting of the Royal Geographical Society, when the International Council was in London in 1907. In January, 1906, we sent a summary on our investigations ("Die norwegischen hydrographischen Untersuchungen im Nordmeere", von Fridtjof Nansen und B. Helland-Hansen, printed as manuscript, and accompanied by our Plates IIXXIV B) to the members of the International Council at their meeting in Amsterdam .
In his paper on "Northern Waters"  describing Amundsen's oceanographic observations in 1901, Nansen has also mentioned some results of our investigations; and in a paper of 1907, Helland-Hansen has described his current-measurements in 1906.
The station-observations made since August, 1902, have been published in the Bulletin, edited by the International Bureau for the Study of the Sea.
Owing to these earlier communications, many points which are discussed in the present report have already been mentioned in the literature by several oceanographers. We may mention, for instance, the vortex-movements and the cyclonic circulation-systems in the Norwegian Sea , the vertical oscillations (and boundary waves) of the intermediate strata, etc. We have not until now, however, had an opportunity of giving a full and complete description of our views, and have not been able to duly consider the use that has already been made of our earlier communications.
BJÖRN HELLAND-HANSEN. FRIDTJOF NANSEN.