APPENDIXES. Remark: The appendixes are published in the name and on the responsibility o f the different authors.

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1 APPENDIXES Remark: The appendixes are published in the name and on the responsibility o f the different authors. 4

2 APPENDIX C ON THE INFLUENCE OF THE EAST ICELANDIC POLAR STREAM ON THE CLIMATIC CHANGES OF THE FAEROE ISLES, THE SHETLANDS AND THE NORTH OF SCOTLAND BY MARTIN KNUDSEN WITH 3 FIGURES IN THE TEXT ( T r a n s l a t e d prom t h e Cxermak by H. M. KYLE)

3 il )^dtographical observations have been carried on in the waters between Scotland and Iceland for a number of years. These observations have shown, that the Golf Stream at all times fills almost the whole region between the Shetland Islands and the Færoes, but that the influence of the Polar Stream can be detected, as a rule, in a lower salinity of the oceanic waters in the immediate neighbourhood of the latter. The Polar Stream is therefore not very far distant. It is obvious beforehand, that the East Icelandic Polar Stream is subject to considerable fluctuations from year to year, both as regards extent and position; yet, the observations make it seem probable, that this stream is always present to the north-west, north and north-east of the Færoes. In winter and spring, the temperature of the southern part of the Polar Stream is much lower, on the surface, than that of the Atlantic Ocean. In the summer and autumn, on the other hand, the difference in temperature between the two is considerably less, as the upper layer of the Polar Stream is warmed by the sun and the wind. Consequently, we find that the East Icelandic Polar Stream has a cooling influence on its surroundings, especially in winter and spring. We may, at present, investigate its influence on the temperature of the air at Thorshavn on the Færoes. When the wind blows over the Færoes from the direction of the East Icelandic Polar Stream, it naturally brings cold with it, especially at the periods of the»year, when the surface of the Polar Stream is greatly cooled, in winter and spring especially therefore. We should therefore expect a very low air-temperature at Thorshavn at these seasons, when a northerly wind is blowing. But the direction of the wind at one single station does not give perfectly trustworthy information of where the wind is actually coming from; to ascertain this, we must consider the position of the centre of the cyclone at the place of observation. For this purpose, I have used the «täglichen synoptischen Wetterkarten für den Nordatlantischen Ocean und die anliegenden Teile der Kontinente, herausgegeben von dem dänischen meteorologischen Institut und der deutschen Seewarte», simultaneously with the Danish meteorological annual reports. That the northerly winds bring cold to the Færoes, is well-known both to the dwellers on these islands and to the meteorologists connected with the climate there. I will not refer any further to this well-known fact, therefore, but I would bring to notice that this effect is to be ascribed to the East Icelandic Polar Stream.

APPENDIX C: KNUDSEN 4 The proof is as follows: when the cyclonic centre is so placed, that the wind which blows over the Færoes, undoubtedly conies from the Kast Icelandic Polar Stream, a regular

4 APPENDIX C: KNUDSEN 4 The proof is as follows: when the cyclonic centre is so placed, that the wind which blows over the Færoes, undoubtedly conies from the Kast Icelandic Polar Stream, a regular fall of the air-temperature below the average will ensue, and this will be the case more in winter and spring than in summer and autumn. It is therefore of interest, to observe the variations caused in the temperature of the air by the reciprocal action of the warm water of the Atlantic Ocean and the cold East Icelandic Polar stream. For this purpose, I have noted down the observations for each single day, over the period from December 1883 to November 1892, and divided the whole material into two groups. I11 the first group, I have placed all the days on which it could be determined with certainty, that the wind came from the region of the Gulf Stream, whilst the second group comprise the days when the wind came from the Polar Stream. Those days have been excluded, on which it could not be concluded with absolute certainty, from the direction of the winds and isobars alone, whether the wind blew from the cold or warm region, even when the temperature of the air left no doubt about the matter. Further, the days of no wind and those on which the wind had changed its direction from the one region to the other, have also been left out of consideration in this investigation. L,astly, those days are also excluded on which the wind had remained weak for one or more days after changing its direction. Experience has shown that the wind, after changing its direction, must blow for some time with a certain force in order to effect any change in the temperature. As a rule, but a few hours are sufficient. O11 separating the material in this way, 987 out of the total 3288 days'fall into the first group and 849 into the second. If we now take the monthly averages for the temperature of the air, we having the following table: Difference between Temperature of the air the air-temperature Wind from the Wind from the with the wind from the Gulf stream and Gulf Stream Polar Stream the wind from the Polar Stream December 6-2 o-o 6'2 January r February o M a rc h i -i 6 7 A p ril M a y '4 3 9 Ju n e J u l y... xo'9 9 4 A u g u s t... n ' September... IO 2u 6-8 3'4 O ctober '6 November i A v e ra g e... O H cb 3-6 4'5

5 5 - APPENDIX C: KNUDSEN W e see fro m th is ta b le, t h a t th e m a x im u m d iffe re n c e in th e a ir - te m p e ra tu re o c c u rs in M a r d i a n d is n o le ss th a n 6 7. F u r th e r, w e se e t h a t th e c o o lin g effect of th e P o la r S tr e a m is in a h ig h d e g re e e v id e n t t h r o u g h o u t th e w h o le y e a r, a n d is m u c h g r e a te r in w in te r a n d s p r in g th a n in s u m m e r (6 7 te m p e ra tu re d iffe re n c e in M a rc h a g a in s t 1-5 in July). W ith r e g a r d to th e te m p e r a tu r e th r o u g h o u t th e y e a r, it h a s to b e re m a rk e d, t h a t th e m in im u m - te m p e r a tu r e o c c u rs in J a n u a r y a n d th e m a x im u m in A u g u s t (end of Ju ly ), w h e n th e w in d c o m e s fro m th e G u lf S tr e a m ; w h ils t, o n th e o th e r h a n d, th e m in im u m fa lls in M a rc h a n d th e m a x im u m in J u l y w h e n th e w in d c o m e s fro m th e E a s t Ic e la n d ic P o la r S tre a m. T h is a p p e a rs c le a rly fro m th e c u rv e s s h o w n in F ig. 1. F r o m th e tw o c o m p o n e n ts, th e a ir - te m p e ra tu re c o n d itio n e d b y th e G u lf S tr e a m a n d t h a t c o n d itio n e d b y th e F a s t Ic e la n d ic P o la r S tre a m, w e m i g h t a s c e r ta in th e m o n th ly a v e ra g e - te m p e ra tu re. I n th is case, h o w ev er, w e s h o u ld n o t le a v e a n y of th e o b s e r v a tio n s o u t of a c c o u n t a n d m u s t in a n y case, h a v e r e g a r d fo r th e n u m b e r of d a y s in c lu d e d in b o th g ro u p s, in o rd e r to o b ta in th e tr u e m e a n -te m p e ra tu re. If w e p a ss o v e r th e te m p e r a tu r e s n o t in c lu d e d a n d fo rm th e a v e r a g e v a lu e fro m th e tw o te m p e r a tu r e - r series, b y g iv in g th e w e ig h t Dtc Jan. Feb M an. J p r il ß!o i Jum Ju/t Jiuy Sept O kt Now. Dec. 987 to th e n u m b e r s o f th e firs t pig J2 series o n th e ta b le a n d th e w e ig h t 849 to th o s e of th e seco n d, w e o b ta in th e m o n th ly te m p e r a tu r e s s h o w n in fo llo w in g tab le. th e first c o lu m n of th e I n th e se c o n d c o lu m n a re g iv e n th e a c tu a l m e a n -te m p e ra tu re s as c a lc u la te d fo r a p e rio d of 25 y e a r s r. I t w ill b e se e n fro m th is ta b le a n d th e a c c o m p a n y in g c u rv e (F ig. 2), t h a t th e tw o se rie s o f th e te m p e ra tu re s a g re e w ell to g e th e r. 1 Meteorologiske Middeltal og Extremer for Færøerne, Island og Grønland. Appendix til det Danske Meteorologiske Instituts Aarbog II Del. pag The upper curve signifies: Temperature with wind from the Gulf Stream, the lower curve. Temperature with wind from the Polar Stream.

APPENDIX C: KNUDSEN 6 Mean-temperatures calculated from the table above True mean-temperatures D ecem ber...... 3'3C 3 4 January... 2 7 3-2 February...... 2-8 3-4 M arch...... 2-5 3'2 A pril.

6 APPENDIX C: KNUDSEN 6 Mean-temperatures calculated from the table above True mean-temperatures D ecem ber '3C 3 4 January February M arch '2 A pril '5" M ay J u n e I 97 July IO'2 io-8 A ugust IO' Septem ber O ctober a 6-6ù N ovem ber The whole year i 6-5 T h at the air-teniperature at Thorshavn lias one minimum in January and another in March, is explained by the fact that the water of the Polar Stream (on account of the m elting ice) is more slowly warmed in early spring than the water of the Gulf Stream. W e can scarcely detect any double m axim um in the summer,because the maxima of the two components lie so close together, th at no partial m axim um is formed between them. T he table shows that the two m axim a are not quite together, in consequence of which the mean-value of the sum m er-tem perature remains almost unchanged for a month Dk Feb. M an j Pr. M ai Jun i ju /i j u j. je p i. oid. Jtov. Occ between 107 and 108. From the figures we see Fig. 21? further, that the air-temperature conditioned by the wind coming from the Gulf Stream, has a secondary maximum in February. This is scarcely characteristic for the climate, however, and is probably referable to the unusual num ber of warm days in February If tem peratureobservations over several years were available, this maximum would undoubtedly disappear. The upper dotted curve signifies: Mean-temperature over 25 years, the lower continuous curve: Mean-temperature from two components.

APPENDIX C: KNUDSEN Since the East Icelandic Polar Stream exercises such a great influence on the climate of the Færoes, the question arises, whether its influence can also reach still further to the

7 APPENDIX C: KNUDSEN Since the East Icelandic Polar Stream exercises such a great influence on the climate of the Færoes, the question arises, whether its influence can also reach still further to the south and east. It can be well understood, that this climatological influence becomes the less, the further we go from the East Icelandic Polar Stream. To determine the action of the Polar Stream on the climate of West Europe would be a very difficult task, demanding considerable material for its solution. I would only remark here, that the winds coming from the Polar Stream in March, would cause the air-temperature on the Shetland Islands and west of Scotland to be SCOT- 10 ca. 3 5 less than the mean-temperature for this month. This, 3-5 is at all events a considerable lowering of the temperature, and it would thus be probable also, that a specially strong flow of the Polar Stream and a corresponding weakening of the Gulf Stream, would lower the air-temperature of the neighbouring countries below the mean-value for considerable periods. If we compare, for example, the position of the boundary-lines representing the 35 /00 isohalin and the 10 isotherm (Fig. 3), in August 1902 and August 1903, we see that these lines extend much further to the south towards Scotland in 1902 than in Corresponding to this, there was a characteristic difference in the air-temperatures of Scotland, England and Norway, as the following table shows:

8 APPENDIX C: KNUDSEN 8 - Sumburgh Head (Shetland) Stornoway (Hebrides)... Shields (E ngland)... Skudeness (Norway)... Average of the observed air-temperatures in August i o '9 I2 'I iri Normal average temperature for August I2' The figures show, that the air-temperatures were considerably lower in August 1902 than in August 1903, and even the latter year was much below the normal as indicated in the last column.

C o r p o r a t e l i f e i n A n c i e n t I n d i a e x p r e s s e d i t s e l f

C H A P T E R I G E N E S I S A N D GROWTH OF G U IL D S C o r p o r a t e l i f e i n A n c i e n t I n d i a e x p r e s s e d i t s e l f i n a v a r i e t y o f f o r m s - s o c i a l, r e l i g i