Lufttrykket 6 har jeg taget efter Kartet Pl. XX XI, 
Luftens Temperatur t efter et Kart over Aarsisothermerne, 
som jeg har publiceret paa et andet Sted'. Idet jeg efter 
Observationerne fra vor Nordhays-Expedition? sætter den 
relative Fugtighed til 88 Procent, bliver, naar # er den til 
Temperaturen ¢ svarende Maximumspændkraft*, 0.3779 e 
= 013719 Xx 088 Hi 4-2, og mant taar 
0 = Oanes, 22. 
9734.0) log 0.047566 = 8.67547. 
RL 
Frictionscoeftienten Å setter jeg for det aabne Hav 
med moderat Søgang lig 0.0000354. 
For den Del af Havet, der er belagt med Is, stiller 
Forholdet sig anderledes, idet Hav-Isens ujevne Overflade 
gjør en større Modstand mod Luftens Bevægelse end selv 
det sterkest oprørte Hav. 
Scoresby siger herom?: | 
“Naar Vinden blæser sterkt henover en sammenhæn- 
gende Pakis eller et Isflak, bliver dens Kraft meget formind- 
sket paa nogle faa Miles Vej. Saaledes kan en Storm ofte 
blæse flere Timer paa den ene Side af et Flak, førend 
den merkes paa den anden, eller, medens der blæser en 
Storm i aabent Vande, ville Skibe i Besæt inden Syns- 
vidde føle kun dens halve Styrke”. 
Paa det aabne Hav er Forholdet v:G omtrent ligt 
7. For den isdækkede Del af Nordhavet sætter jeg det 
til 5. Dette svarer, som det vil sees af de nys citerede 
Steder, til en Frictionscoefficient af 0.00008, eller den, som 
er fundet for Nordamerika. Isgrændsen setter jeg mellem 
Isothermerne for 0° og + 1° paa Kartet Pl. XVI, saavel 
i Østhavet som i Gronlandshavet. 
Efter disse Formler og Constanter er Vindens Ret- 
ning og Hastighed beregnet for et stort Antal Punkter, 
jevnt fordelte over Nordhavet. Resultaterne afsattes 1 et 
Kart, paa hvilket der blev optrukket Pile i Vindens Ret- 
ning og Linier for ligestor Vindhastighed. Over det aabne 
Hav er Vindens Afbøjningsvinkel omkring 75°, over Isen 
er den omkring 609, Paa det første Sted danner Vinden 
en Vinkel af 15° med Isobaren, paa det andet 30". Kar- 
tet, Pl. XX XI, viser det resulterende. Vindsystem. Pilene 
flyve i Vindens Retning. Antallet af Fjer paa Pilene an- 
giver Hastigheden i Meter pr. Secund. Ingen Fjer, men 
en Spids paa Pilen, betegner en Hastighed af mindre end 
0.5 Meter. Ved Stationerne paa Island, Færøerne og Fyr- 
Stationer paa Norges Kyst er, ved tykkere Pile med Spids, 
angivet Retningen af den i Aarets Løb hyppigste Vind. 
' Zeitschrift der dsterreichischen Gesellschaft fiir Meteorologie, 
i884, Aprilheft. 
? Den norske Nordhavs-Expedition. 
So Nil, nere 
3 Broch. 
4 
H. Mohn. Meteorologi, 
Tension de la vapeur d'eau. Travaux ete. 
Zeitschrift der dsterreichischen Gesellschaft fiir Meteorologie, 
1877, S. 53 og 58. Sprungs Meteorologie, S. 121 og 123. 
> An Account of the Arctic Regions, I, S 296 og 297. 
The pressure, b, I took from the map, Pl. X XXI, the 
temperature of the air, t, from a map of the isotherms for 
the year, that I have published elsewhere. Now putting, 
in accordance with the observations from the North-Atlantic 
Expedition,* the relative humidity at 88 per cent, then, as- 
suming # as the maximum-tension corresponding to the 
temperature %,> O3779 el = 03779 x 0,88 H = 1 £ 
and we have — 
0 = 0.047366. 
ene log 0.047366 = 8.67547. 
For the open sea, when moderately agitated, I put 
the friction-coefficient, Å, at 0.000035. * 
As regards the part of the ocean covered with ice, 
the case is different, the rough surface of sea-ice exerting a 
greater resistance to the motion of the air than does even 
the most agitated sea. 
Scoresby remarks on this subject®: — 
“When the wind blows forcibly across a solid pack 
or field of ice, its power is much diminished ere it traverses 
many miles: Insomuch, that a storm will frequently blow 
for several hours on one side of a field, before it be per- 
ceptible on the other; and, while a storm prevails in open 
water, ships beset within sight, will not experience one- 
half of its severity.” 
Out at sea, the ratio v:G is about equal to 7. 
For the ice-covered part of the North Ocean, I put it at 
5. This corresponds, as will appear from the passages in 
the works cited above, to a friction-coefficient of 0.00008, 
or that found for North America. The ice-limit I put 
between the isotherms for 0° and + 1°, as given on the 
map, Pl. XVI, both in the Barents Sea and in the Green- 
land Sea. ; 
From these formule and constants, the direction and 
velocity of the wind has been computed for a great num- 
ber of points, uniformly distributed over the North Ocean. 
The results I set down in a map, on which arrows were 
drawn in the direction of the wind, and lines for equal 
velocity of the wind. Over the open sea, the wind’s angle 
of deviation is about 75°, over the ice it is about 60°. Over 
the open sea, the wind forms with the isobar an angle of 
15°, over the ice an angle of 30°. The map, Pl. XX XI, 
The arrows fly in the 
The number of feathers on an 
arrow indicate the velocity in metres per second. No feather 
at all, but merely a point, denotes a velocity of less than 
0.5 metre. At the Stations on Iceland, the Færoes, and 
some Lighthouse-Stations along the coast of Norway, thicker 
exhibits the resulting wind-system. 
direction of the wind. 
' Zeitschrift der dsterreichischen Gesellschaft fiir Meteorologie, 
1884, A prilheft. 
> The Norwegian North-Atlantic Expedition. 
teorology, p- 
3 
H. Mohn. Me- 
121, and following. 
Travaux ete. 
Zeitschrift der österreichisehen Gesellschaft fiir Meteorologie, 
1877, pp. 53 and 58. 
Broch. Tension de la vapeur d'eau. 
4 
Sprungs Meteorologie, pp. 121 and 123. 
> An Account of the Arctic Regions, Vol. I, pp. 296 and 297. 
