- s 



APPENDIX A: PETTERSSON 



Statement is born out by the synchronous variation of the sahnity. The expansion of 

 the North Cape current is accompanied by an abundant immigration of cod and had- 

 dock, of which more -will be said later. 



1898 1899 1900 



■vivir\Tiijxx:xi?aii nrarvvvivnvmEcxxiJUinnirv^vvi'vii vm ix x xi xn 



Fig. 2. Variations of tlie temperature of the water in the deep (250 m. Motowskijfjord), after Knipowitsch 



The last projection of the North Sea current of Atlantic water enters the deep- Skager Rak 

 channel of the Skager Rak as undercurrent. Observations comprising more than ten years, 

 indicate an annual expansion in these parts of the deeper waterlayers, which usually cul- 

 minates in November, but in some years is retarded to February or longer. The accom- 

 panying diagrams, of a section between Skagen and Christiansand (Norway) in August 

 and November 1893 and in February 1894, show the Atlantic water (here undercurrent) 

 shaded in the figures, as in previous sections. From these diagrams it will be seen, that the 

 expansion that year culminated in November, a fact which is borne out by the extension 

 of the waterlayer and the rise of temperature aUke, the latter also attaining its maximum 

 during this period. In February 1894, "^^ ^tib of the Atlantic water sets in. Beside the 

 February section from 1894, there is another of the corresponding month 1896. This is 

 altogether different : the Atlantic water being then still in flood. Here two different types 

 of years are represented. If 1893 — 94 be chosen as typical of the conditions of normal 

 years, February 1896 must be considered as representing another different set of years. 



As in the Barents Sea, the flooding of Atlantic water sends a heatwave towards the Heatwave in 

 mouth of the Kola-fjord, so the accumulation of Atlantic water in the Skager Rak depths ""^ Kattegat 

 sets up a heatwave, which enters the Belts through the Kattegat ^ The effect of this under- 

 current of southern Bank- Water entering through the deep channels of the Kattegat is, that 

 the deepwater of the western part of the Baltic and the Belt-Sea attains its maximum of 

 temperature in November. In the Baltic proper, even as far as east of Bornholm, the 

 undercurrent penetrates during most years, replacing the relatively cold water of the 

 previous winter with warmer. The most remarkable circumstance of this phenomenon 

 is, that the invading water does not enter as a bottom current into the deep basin east of 

 Bornholm, but occupies an intermediary space between the bottom layer and the surface 

 layer, thus forming a wedge of warmer water between two cold layers. 



■ M. Knudsen, Beretning fra Kommissionen for videnskabelij 

 II. 1899. p. 49. 



Undersogelse af de dan.ske Farvande. 



