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GREENLAND AND ARCTIC AMERICA.
The information we have on the winds, as well as on the general climate of Arctic America and the adjacent islands, is more extensive than that on any other Arctic region, Northern Norway excepted. Our knowledge of these regions is mostly due to Arctic explorations. The Arctic Archipelago, north of the American Continent and west of Greenland, was explored almost continuously by British expeditions for more than thirty-five years (1818–1855), in search of a northwestern passage.
The results of these expeditions are of high value to science, especially as the inducements to explorations in this direction can scarcely ever return. and straits between the islands are probably the most ice-bound in the world.
Smith's Sound and Northern Greenland have been explored by the American expeditions of Kane, Hayes, and Hall.
According to the most authentic Arctic authorities, Smith's Sound offers the best route to the Pole, the sea between Spitzbergen and Nova Zembla perhaps alone excepted. It is entirely frozen only a short time, and does not present serious obstacles to navigation in steamers. This gives us reason to expect further knowledge of those regions which were so successfully penetrated by American explorers, with very inadequate means at their disposal.
A German expedition wintered in Eastern Greenland, 75° N. Lat.
We know much less of Western Arctic America; few expeditions having wintered there west of 100°. Our knowledge of the interior of British America is also less than of the Arctic Archipelago, though it is much more easy of access. More information relative to this region is very desirable.
Our knowledge of the climate of Arctic regions generally having been mainly derived from observations made in the Arctic Archipelago of America and in Smith's Sound, it is necessary therefore to inquire into the geographical position of these regions. They are situated from nearly due north to W. N. W. of Iceland, where, as was stated above, exists the lowest pressure of the northern hemisphere, nearly the whole year round, but especially in winter. This must lead to the prevalence of northerly and westerly winds. Accordingly in the stations in Smith's Sound northeasterly winds were found dominant, owing to the influence of the strait, and also to the position, N. N. W. of Iceland. (See Map, Pl. 2.)
There are great discrepancies in the results obtained at the different stations,
but these are easily accounted for, if we remember that the period of observation was short, mostly one year only, and that the climate of the Arctic regions is very changeable; still there are some differences in the direction of the winds which can only be ascribed to their geographical position. Thus Northern Greenland has the greatest prevalence of the true polar winds, northeast, and this is due in no small degree to its proximity to Iceland, as well as to the open water of Smith's Sound near a very cold continental area.
The most northerly stations west of Smith's Sound, as Northumberland Sound and Port Refuge, have the least amount of northern winds. This is, no doubt, owing to their distance from Iceland, and, probably also, to a partly open sea to the northward of them. If there is really an open sea in this direction, the pressure there must be lower in winter than on the ice-bound straits of the Archipelago. This would give rise to southerly winds to equalize the pressure, and thus explain the greater number of these winds in Northumberland Sound and Port Refuge. They do not prevail at these places, because the depression about Iceland is still felt there as well as the depression which must exist on the open waters of Davis' Strait and Smith's Sound. As the other stations of the Archipelago, except Melville and Dealy Island, are much nearer to Davis' Strait, they must feel its influence much more, while a great extent of islands and frozen bays and sounds separate them from the northern partly open Polar Sea.
The prevailing northerly winds in summer can be explained partly by the same cause as those of winter—the low pressure about Iceland. It is true the barometer near Iceland is not as low in summer as in winter. But in the Arctic zone of America the pressure rises also, especially from February to May; in the last-named month it is the highest of the year in most of the stations of this region.
It is probable that the pressure continues to rise in the circum-polar zone till July, thus causing the northerly winds of Arctic America. At this season air is also drawn towards the interior of North America, especially towards the region between the Rocky Mountains and 95° W. Long. Arctic America is noted for its frequent calms in the colder part of the
of the year—a feature observed by nearly all who wintered in these regions. They are, however, recorded in a very discordant manner in the journals of observations, showing there was a great difference in the meaning of the word “ calm.” This want of agreement has prevented a more elaborate discussion of this phenomenon, one of the most important in regard to the movements of the atmosphere.
Dr. Bessels has calculated the percentage of what he calls “ absolute calms,” for the hours when a self-registering wind-vane did not indicate any movement of air whatever, for the second winter-harbor of the U. S. Expedition, under Capt. Hall, at Polaris House or Lifeboat Cove.
Hours of Absolute Calm in 1000.
March, 1873, 188
116 Average for seven months, 140. I should remark, that in many of the stations the proportion of calms increases
towards March and April. In these months the cold is still intense in this region, and the pressure generally higher, so that barometric poles or areas of highest pressure are frequently met with. They are generally accompanied with calms or light winds. On the other hand, the indraught towards Iceland is less, as pressure has also risen there. (See Tables, Zones 2, 3, 4, and 5.)
In cold continental areas of lower latitudes, especially in Siberia, the greatest number of calms will be experienced in mid-winter, the time of lowest temperature and highest pressure.
In March and April, when temperature is much higher, pressure decreases, and so also the number of calms.
The following figures give the percentage of winds in Greenland. Winter and summer are chosen as the two contrasting seasons of the year.
All these stations except Sabine Island are situated on the western shore of the greatest island of the world, an island covered with large sheets of ice, and the temperature of which is much below that of the surrounding seas in winter, spring, and autumn; Smith's Sound is open the greater part of the year, though bearing large floating icebergs. Monsoon winds must be expected in these conditions, and this is really the case.
The winds of Polaris Bay have a peculiar interest, this being the most northerly station at which civilized man has ever wintered. Polar winds prevail largely in spring and winter. Yet there is a great difference between the N. E. and E. winds. The second prevail if the number alone is regarded, but the N. E. prevail
· In all cases, except when specified, the percentages are calculated from the winds collected by Prof. Coffin. . From the observations of Dr. Bessels, of Capt. Hall's Expedition.
Observations of the Second German Polar Expedition, under Capt. Koldewey. * I owe this information on the winds of Polaris Bay and Lifeboat Cove to Dr. Bessels, who has kindly permitted the use of his observations,
largely if we take into account the number of miles. And this may be done safely, as the expedition of Capt. Hall had an anemograph of Robinson's plan. The east winds then seem to be a weak local land-wind, caused by the difference of temperature of land and sea. The N. E. winds, on the contrary, are the true polar currents, flowing towards the barometric depression about Iceland.
In summer the S. W. wind prevails as to time, but the excess is on the side of the N. E., if the number of miles is considered, but of much less amount than in winter and spring.
In the second winter station of Capt. Hall's party, Lifeboat Cove or Polaris House, as also in Hayes's Station, Port Foulke, in the vicinity, the N. E. prevail even more than in Polaris Bay in winter and spring. The W. and N. W. are entirely wanting
In the tables of Professor Coffin, the winds at Rensselaer Harbor, Kane's winter station, were recorded with reference to the magnetic direction. As the magnetic declination is known to be 108° 12' W., I give below the true mean direction of the wind in this locality, and also that recently calculated by Dr. Bessels for Polaris Bay. In the Map, Pl. 2, the true direction is given.
The observations of Rensselaer Bay are thus shown to agree, to a considerable extent, with those of the surrounding stations. The winds are more easterly than at Polaris Bay at all seasons, and do not vary as much as at that station, the difference between winter and summer being only 91° instead of 161o. See Map, Pl. 2.
The Danish settlements of Northern and Southern Greenland (all on the west coast of the island), Upernavik, Jacobshavn, and Godthaab, have largely prevailing east winds (from the land) in winter, and west winds (from the sea) in summer. As the force of the winds has not been accurately ascertained, we cannot say whether the N. E. are much stronger than the East, as in Polaris Bay. In the summer the rocky surface of the interior (as Greenland is not all covered with ice) is highly heated by the sun, it draws in the air from the colder sea, which is cooled by the large number of icebergs floating southward.
We know much less about Eastern Greenland, the country being entirely uninhabited. Yet the 2d German polar expedition having passed a year near Sabine Island, 75° L. N., near the coast, we are able to say that the prevailing winds are N., especially in spring, autumn, and winter, while S. winds are nearly as frequent as N. in summer. The N. prevail here to a less degree than the N. E. at Lifeboat Cove and Port Foulke; but it would be rash to decide from so short a period and so few observations that the polar winds are really less prevailing in the east than in the west of Northern Greenland. The eastern coast of the island
being nearer to Iceland, where pressure is low, we might infer that the contrary should be the case, if all local influences were eliminated. Nearly all the storms near Sabine Island come from the N., and the mean force of this wind is very much greater than that of any other wind.
The constancy of the polar current in Northern Greenland is indirectly proved by the small precipitation of rain and snow. The quantity of snow falling at Polaris Bay and Lifeboat Cove was scarcely measurable, according to Dr. Bessels. He thinks the glaciers of Northern Greenland are the remnant of a former age, when the climate was different. The snow and ice that melt in every summer are not now replaced by new snow, so that the glaciers must be decreasing.
The German expedition did not encounter a heavy snow-fall, and the parties who, in sledges, explored the interior, were quite astonished at the constant brilliancy of the sunshine of the Greenland summer.
In Arctic countries the sea is warmer than the land in the mean of the year; during a very short time only, in summer, are the conditions reversed. The pressure is generally higher on land, so that we must expect to see a prevalence of landwinds in the mean of the year. In looking at the map of the polar regions (Plate 2) an easterly mean direction is seen to prevail in all stations in Greenland, that have the open sea to the westward; and a westerly in the stations of the Arctic Archipelago, which have the sea to the eastward.
By sea, is meant here the more or less open waters of Baffin's Bay and Davis Strait, and not the more ice-bound straits and inlets of the archipelago. Ikogmut and St. Michael in northern Alaska have easterly winds, directed towards Behring Strait. In Ustyansk, in the extreme north of eastern Siberia, the mean yearly direction is nearly due south-as we might infer from the fact that the Arctic Ocean lies to the north of this place. Hammerfest, Vardo, and Bossekop, in extreme northern Norway, have also prevailing southerly winds for a similar reason.
The extreme prevalence of land-bound (Mediterranean) seas, north of the North American continent, greatly affect the character of the region considered in a climatic point of view. As land-bound seas in these latitudes will be also ice-bound, the air over them would cool as over a continent, so that places situated on the shores of such seas will have a cold continental climate in winter, spring, and autumn. This cold will not, however, be followed by a comparatively warm summer, as is the case on polar continents far from the influence of the sea. The melting ice over the sea absorbs the heat of the sun's rays. Thus we have a continental climate during three-quarters of the year, and an oceanic during the remaining summer quarter. This is the case in the Arctic Archipelago. It has one of the coldest climates of the world, the winter being even colder than in northern Greenland, and only a little warmer than in Iakutsk in eastern Siberia, and the summer also extremely cold.
The percentage of winds is as follows:
· See “ Die Zweite Deutsche Nordpolarfahrt,” Leipzig, 1874.