Climate of Greenland
EA-General. Greenland-Svalbard
(William H. Hobbs)
CLIMATE OF GREENLAND
The climate of Greenland has been learned by the explorers, who
have traveled over it. Its expanse of glacial ice and its inhospitable
climatic conditions have, except during a single year, kept meteorologists
from establishing their stations except at the heads of fjords along the
coast.
The first important invasion of Greenland by an exploring party was
that of Baron Adolf Erik Nordenskiöld in 1883, who made his penetration
from near Disko Bay on the west coast in latitude 68° N. Southeast winds
of great force were faced for a distance estimated to be 100 km. (1).
Complete transections of the island were first made by the great
explorers, Nansen in South Greenland in 1888 and Peary in two double tran–
sections of far Northern Greenland in 1892 and 1895, after he had already
made deep penetrations from the west coast.
Nansen's transection was made from the east coast, climbing in the
face of fierce blizzards to an imperceptible divide at an elevation of
9,000 feet and then, with a small sail raised on the sled, coasting down
the west side. Of the winds encountered he wrote (2):
"The prevailing winds were therefore land winds which blew from
the interior toward both coasts. This points to a maximum air pressure in
the interior and to air currents toward it which flow off on both sides
over the slope toward the sea."
EA-General. Hobbs: Greenland-Svalbard
This was the initial discovery of the glacial anticyclone of Greenland,
which was, as we shall see, to be confirmed throughout the next half-century
by all the great Greenland explorers, two of them, Alfred De Quervain and
Alfred Wegener, meteorologists.
Peary's summary statement on the climate of Greenland
. Next after
Nansen to describe the climate of Greenland was Robert E. Peary, greatest
of polar explorers. After more than 3,000 miles of sledge travel over Green–
land, Peary summed up the pattern of its wind system in the following sen–
tences (3):
" ... the direction of the wind of the "Great Ice" of Greenland
is invariably radial from the center outward, normal to the nearest part
of the coastland ribbon. So steady is this wind, and so closely does it
adhere to this normal course, that I can liken it
[:
]
only to the flow of
a sheet of water descending the slopes from the central interior to the
coast. The direction of the nearest land is always easily determinable
in this way. The neighborhood of great fjords is always indicated by a
change in the wind's direction; and the crossing of a divide, by an area
of calm or variable winds, followed by wind in the opposite direction,
independent of any indications of the barometer."
This wind pattern above the inland ice of Greenland, which has the
model of a gigantic cake of very thin batter, can be summed up by the single
word
katabatic,
down-slope, except as the winds are deviated clockwise by as
much as half a right angle, due to the earth's axial rotation.
Like other explorers, Peary had observed the winds of Greenland where
they are, and not from permanent stations in fixed positions outside. For
this reason they have not been taken into account by professional meteorolo–
gists. Moreover, the direction and force of the wind was, as a rule, not
measured on precision instruments with data which can be expressed in numerical
figures.
The direction of the wind and its force were learned by him because he
had had to fact it while the sled dogs toiled strenuously, not against a
EA-General. Hobbs: Greenland-Svalbard
perceptible slope, but only against the wind; or,
per contra
, with sail
raised for a tail wind, all his efforts given over to applying a brake
to prevent the sled from overrunning the dogs. Wind force was registered
also in the daily runs as plotted on the chart of the course. Those on
the downslope had been two or three times as long as those on the ascent.
In camp the tent always had to be set up with the opening on the lee side,
or it would have been blown away.
While in camp, wind force and direction had been noted by the bellying–
in of tent walls, which pressed against the bodies of the men in their
cramped quarters. Everywhere except within a cold interior area, the
dominant wind direction is graven on the hard-packed snow in the furrows
of its surface — the
sastrugi
. These are so constant in direction as to
be used in laying the course.
Over the inland ice the wind direction and its force are also indicated
by the motion of fine snow, which is contin
au
^
ua
^
lly drifting outward over its
surface toward all coasts. To cite Peary again (4):
"There is one thing of special interest to the glacialist--the
transportation of snow on the ice-cap by the wind. No one who has not
been there can have any conception of its magnitude. The wind is always
blowing, and blowing always on lines which would be gravity lines from
the interior . . . I have walked for days in an incessant sibilant drift
of flying snow, rising to the height of the knees, sometimes to the height
of the head. If the wind becomes a gale, the air will be thick with the
blinding drift to the height of 100 feet or more . . . When it is remembered
that this flow of the atmosphere from the cold heights of the interior ice–
cap to the lower land of the coast is going on throughout the year with
greater or less intensity, . .. . it will be seen that the above assumption
is not excessive."
Observations made by the Greenland exploring expedition of 1906-08
.
After Peary's North Greenland explorations, European expeditions, mainly
from Denmark, followed during the early years of the 20th century. The
first of these was a Danish one to northeast Greenland in the years 1906-08,
EA-General. Hobbs: Greenland-Svalbard
led by Mylius Erichsen. On his staff were three meteorologists: Alfred
Wegener, W. Brand, and the then student, Peter Freuchen. Two meteorological
stations were set up, one of them on the coast in latitude 77° N., where
Wegener and Brand were located. Wegener at the base station had kite and
captive-balloon equipment. With this he was able to establish the fact
that the ground observations made in a station on the coast (where it was
shielded by rock cliffs) gave no true picture of the local winds (5).
These were by the aerological aids first encountered at an elevation of
1,000 meters, the height of the rock walls. All strong winds were found
to blow from the northwest, the down-slope direction of the inland ice,
with the 45° clockwise deviation. Up to that time the prevailing easterly
winds everywhere encountered off the northwest Greenland coast had been
supposed to have come across the island from the East Greenland Sea. These
observations of Wegener, the first ever to be made in northeast Greenland,
thus were the first from a meteorologist to confirm Peary's law of out–
blowing winds.
Wegener's observations were also significant in showing that meteoro–
logical ground observations made in a fjord bottom near the coast do not
give reliable results with regard to the local winds. Minrich Rink, long
a keen observer while an inspector in West Greenland, had learned this as a
result of his long residence there. On many occasions the overriding of
the bottom currents by strong outward-blowing winds would be made known
by the roaring of the blizzard overhead, which sometimes continued for
days, but with no ripple to be seen on the water of the fjord below (6).
At other times the wind would get down into the fjord, but with a quite
different direction, since it always blew parallel to the local fjord walls.
EA-General. Hobbs: Greenland-Svalbard
This vitally important knowledge the writer acquired the hard way when
a Greenland tenderfoot a score of years ago. Alone in a small rowboat
on a crooked fjord, the high waves threatened to upset his craft and pre–
cipitate him into the icy water. He rowed madely to double a point which
was in sight ahead. When around the bend, the situation was still quite
unchanged.
The air pressure, then, is the only meteorological ground unit which
can be reliably observed at a fjord-bottom station.
Dating
[:
]
from this, his first of several Greenland expeditions,
Alfred Wegener became a strong supporter of the Greenland anticyclone and
continued to be to his tragic death on the ice cap in 1930.
Glacial anticyclones over both Greenland and the Antarctic.
The only
existing continental glaciers are those over Greenland and the Antarctic
continent. The latter is of about the area of the entire United States;
the former, of that part of it which is east of the Mississippi River. By
assembling the wind observations made by all the sledging parties when
traveling over the inland ice covering these great areas, the writer was
in 1910 able to show that both areas
^
were
^
alike under a system of outblowing
winds, and he gave to each of them the name
glacial anticyclone
(7).
Observations made on the Greenland expeditions of 1912-13.
The
years 1912 and 1913 were to see no less than four Greenland exploring
expeditions, three of them complete transections and one of them a double
cross-section. Three were Danish and one Swiss. All were able to confirm
the everywhere-prevailing outblowing winds of the glacial anticyclone.
The Swiss expedition of 1912 was led by the distinguished explorer–
meteorologist, Alfred De Quervain, who made a
[:
]
transection of the inland
EA-General. Hobbs: Greenland-Svalbard
ice from Disko Bay on the west coast to Angmagssalik on the east coast,
a south-central cross-section. He encountered the same pattern of winds
that had been described by Peary, and since he passed through the central
area of the island — something that peary had not done — he found there
a cold area sharply set off from that over the inland ice outside. This
was shown both by its much lower air temperature and by the three-times–
greater daily range of temperature, though the common border was marked
by no topographical break in the surface (8). This central area is quite
naturally assumed to be the interior area of downdraft which feeds the
outblowing winds.
The second Danish northeast Greenland expedition was led by Capt. J.P.
Koch. Its scientific reports were written jointly by him and his principal
companion, Alfred Wegener (9). A winter was spent at station Borg, set up
for meteorological and other scientific observations on the inland ice of
northeast Greenland, and the following summer a great transection of the
island was made to the west coast at Pröven (latitude 72° 30′N.). The
pattern of the winds encountered illustrated the glacial anticyclone in
great perfection, and they confirmed the central downdraft area, as
Dr. De Quervain had already done.
Knud Rasmussen, who with Peter Freuchen made a double crossing in
north Greenland near, but farther south than, the southernmost of Peary's
crossings, confirmed the pattern of outblowing winds (10).
Ejnar Mikkelsen, in the years 1909-12, directed a Danish expedition
in search of the remains of the lost Erichsen party and to find, if possible,
their maps and diaries. He made an interior sledge journey from Danmarkshavn
over the ice cap in a north-northwesterly direction to Independence Fjord.
EA-General. Hobbs: Greenland-Svalbard
The winds encountered throughout were all from the westerly quarter down
the slope of the inland ice (11).
Rasmussen's Second Thule Expedition of 1916-18, this time across the
inland ice of northwest Greenland (12), and Lauge Koch's quite remarkable
sledge journeys of 1920-23 on and about northeast Greenland (13), also
revealed the some down-slope winds everywhere.
In 1926 this writer brought together all the scattered meteorological
data derived from both Greenland and the Antarctic up to that time and
issued then under the title,
The Glacial Anticyclones
(14). The Antarctic
data of most significance had been those observed over the inland ice by
sledging parties, and these clearly revealed the Antarctic anticyclones.
These winds had not, however, been taken account of by the professional
meteorologists, who had occupied the coastal weather stations; and, since
the theory of polar cyclones was at the time the dominant one, the reaction
of the meteorological profession was that,
if
such an anticy
^
c
^
lone actually
lay above the inland ica, it must be thin and overlaid by a cyclone.
The University of Michigan Greenland expeditions, 1926-33.
It thus
became an important inquiry to measure, if possible, the thickness of the
layer of outblowing winds and fix the altitude of its ceiling. To pursue
this inquiry in Greenland, this writer
[:
]
organized the Greenland expeditions
of the University of Michigan and directed the four which were carried out
between 1926 and 1931. The fifth was directed by his colleague, Dr. Ralph L.
Belknap. During these years four aerological stations were set up close
to the glacier front in West Greenland: at Ivigtut in latitude 61° N., at
Mount Evans in latitude 67° 30′, at Camp Scott in latitude 73°, and at
Peary Lodge in latitude 74° 15′. At each of these stations daily pilot
baloons were sent up and their paths followed by theodolite to an average
EA-General. Hobbs: Greenland-Svalbard
height of 7,000 meters but with many to much higher levels. Each of the
four stations was maintained for at least a year, the main station of
Mount Evans for two years, and at this station 776 pilot balloon ascents
were carried out. By these
^
^
investigations the ceiling of the outblowing
winds was found, near the west border of the inland ice, to be about
3,000 meters or roughly 2 miles (15).
Alfred Wegener's German expedition of 1929-31 to take measurements
of the Greenland anticyclone
. A preliminary expedition to fix the position
of the stations for the main expedition was carried out in the summer of
1929. On this, Dr. Wegener was accompanied by three well-known meteorologists:
Johannes Georgi, Fritz Löwe, and Ernst Sorge. All were destined to play
important roles on the main expedition. This preliminary expedition made
two deep penetrations over the inland ice to distances of 100 and 130 miles,
respectively. They were made in the face of strong head winds during the
inward journey, but with tail winds on the return (16).
The plan of the larger expedition, for the purpose of
[:
]
^
deriving
^
measure–
ments of the glacial anticyclone, was outlined by Alfred Wegner in an
avant propos
issued in 1928 (17). To cite:
On the wind relationships in greater elevations we have up to
the present those only from West Greenland (De Quervain, Hobbs).
If one is to understand in toto the kinematics of the glacial anti–
cyclone one must study the distribution of the wind and likewise the
temperature distribution along a complete west-east cross-section,
and, if possible, as far up as the stratosphere. It is still an
open question whether the so astoundingly regular air distribution
of the glacial anticyclone extends upward to the border of the
stratosphere, or is earlier replaced by winds flowing in above . . . .
. . . The stations must be along a west-east cross-section of
Greenland, thus, two in western and eastern coast regions, and one
in the central n
e
^
é
^
v
e
^
é
^
region within the realm of the cold core of the
anticyclone.
The main "Alfred Wegener Expedition" was carried out as planned, except
that Dr. Georgi, who was in charge of the important central station of
EA-General. Hobbs: Greenland-Svalbard
Eismitte, was, even as late as October, not yet supplied with his prefabri–
cated winter house, adequate food or fuel supplies for the winter months,
or all of his qerological equipment. At great risk to his life, Wegener
set out with a great sledging caravan to take in these needed supplies,
but he encountered such fierce head winds that most of the sleds had to be
sent back. With Dr. Löwe and one heroic Eskimo, Rasmus Willem, the leader
pushed on with three sleds, but met with such violent surges of the out–
blowing winds that he was compelled to jettison most of his cargo and
arrived at the station with Dr. Löwe's feet so badly frozen that he had to
be left there and have his toes amputated. On November 1, his 50th birthday,
Wegener and the faithful Rasmus left Eismitte for the coast, but both
perished on the way out.
With the extra mouth to feed, Georgi and his staff at Eismitte dug a
cave snowhouse, husbanded to the limit the scanty food and fuel, survived
the winter, and performed the planned research - a really great accomplishment.
The cyclones which arrive at Greenland's west coast are switched north
.
While Wegener's expedition was in occupation of its three "profile" aerological
stations, the British Arctic Air Route Expedition, led by the youthful Gino
Watkins, was maintaining for a period of 7 winter months an "Ice Cap station"
in the Greenland interior near latitude 68° N. For the full year it main–
tained also a base station on the east coast, near Angmagssalik, in latitude
66° N. Neither station had aerological equipment (18). At the same time,
also, the University of Michigan Greenland expeditions were maintaining
two aerological stations, one at Ivigtut in extreme south Greenland
(Latitude 61° 30′N.), the other on the west coast in latitude 73° N.
This unique situation, with 7 expedition stations operating, 2 in the
EA-General. Hobbs: Greenland-Svalbard
interior and 5 carrying out upper-air studies, suggested to this writer
that (by combining in a post-mortem operation after the reports from the
Danish coastal stations without radio had become available) it would be
possible to trace the tracks of the cyclones which had arrived at the west
coast during the year, for the pressures recorded at the coast stations
could be relied upon. The suggestion was made to Dr. Georgi, who had been
director of the Eismitte station. He gladly consented, the British, German,
American, and Danish observation data were brought together, and the inquiry
was carried out. This study revealed that those cyclones which had reached
the west coast from a westerly quarter had been turned from their courses
and diverted north up Davis Strait and Baffin Bay. Cyclones on tracks
farther south which had passed Cape Farewell over the Atlantic had moved up
the East Greenland Sea (19).
A somewhat similar inquiry, and with similar results, was conducted
by R. L. Belknap for 1932-33 (Second International Polar Year), another
favorable year for such study (20). The Wegener expedition at its West
Station also conducted such an inquiry, with the result that no cyclone was
found to have made the transit of Greenland (21). Of the wind constancy
Kurt Wegener says: "Along the route of the expedition from West Station
to Eismitte, it blows from southeast to east southeast" (22).
At West Station, located between the Michigan stations, a closely
agreeing value was obtained for the thickness of the layer of outblowing
winds. From a locality 1,000 meters higher and over the edge of the
inland ice the ceiling was found at 4,000 m. to compare with 3,000 m.
measured at the four Michigan border stations (23, p. 31).
The downdraft area of central Greenland
. At Eismitte, within the
EA-General. Hobbs: Greenland-Svalbard
downdraft core of the anticyclone, Georgi found the thickness of this
bottom layer of "heavy air" to be only 400 m., not 3,000 m. as at the
margin of the inland ice in West Greenland. All his attempts to get kites
above this ceiling were futile. Further evidence of the downdraft appears
on his daily weather chart for the entire period of occupation. On this
chart air pressure and temperature can generally be seen to vary together,
not in reciprocal relation, as is common where air currents move laterally
(24). With increased vigor of downdraft — higher air pressure — the
adiabatic elevation of the temperature of the sinking air should increase
and be registered in the near-surface layers.
Quite unexpectedly, a remarkable proof of the strong downdraft within
the core of the anticyclone was furnished by a flight across Greenland in
an effort to find the lost Wegener. The German Flight Captain Wolfgang
von Gronau, in April 1931, flew direct from Scoresby Sound, on the East
Greenland coast in latitude 70° N., southwestward to Sukkertoppen, on the
west coast in latitude 66°. This took him through the core of the anti–
cyclone a little to the south of the Eismitte station. His plane, despite all
his efforts to prevent it, was forced down by the downdraft, but when near
the glacier surface he was able to level off and continue his flight so
near to the surface that his radio antenna dragged begind the surface snow.
He had entered the 400-meter-thick layer of the "heavy air" which flows
outward along the surface (New York
Times,
August 19, 1931, p.3, col.8).
One of the early plane crossings during World War II was less fortunate
and crashed within the core area.
The core or "n
e
^
é
^
v
e
^
é
^
region" of the anticyclone was further proved to
be an area of very heavy snow precipitation. Fine dry snow was separated
EA-General. Hobbs: Greenland-Svalbard
out from the near-surface "heavy air" layer. On 213 days out of 265 (58%)
snow was precipitated, and on 191 of these it was observed to be drifting
out. At the other interior weather station within the core area, the
British "Ice Cap station," snow was precipitated on 57 days of the 181
that it was occupied — some without observations — and on 23 of these it
was observed to be drifting (25). Such heavy precipitation within the core
of the anticyclone explains the origin of the stupendous quantities of snow
which have been observed by all sledging parties to be almost constantly
drifting outward over the flanks of the inland ice. Its only source is
obviously the ice spicules of the cirrus and other closely related cloud forms,
the dominant types observed above Eismitte. These would be adiabatically
vaporized in the downdraft and be reprecipitated as they approached the
glacier surface. At the end of the long winter season much of this snow
is found piled up outside. That drifted during the summer months is largely
melted within an intramarginal zone, where it produces the superglacial lakes
and rivers always found there late in the season.
The observations made at all three profile stations of the Wegener
expedition confirmed the presence of the glacial anticyclone. To cite
Kurt Wegener's final conclusions (26):
The observations of the wind at the profile stations show that
the "heavy wind" already known for a long time is the charachteristic
wind of the inland ice which everywhere flows off the inland ice (p. 4).
This phenomenon Hobbs has called the glacial anticyclone. As type
examples of the "glacial anticyclone," which holds good for all seasons
of the year, are the South Polar region and Greenland...... The statis–
tical data show us that we have to do with a high pressure area at
the level of the sea, from which on all sides air is streaming out .....
The physical explanation of the glacial high pressure area ..... is ob–
viously due to the outgoing heat irradiation of the ice surface (
Boden
).
This has for a consequence that far up in the stratosphere the air–
masses over Greenland sink down, stream out below, and from high
outside a new instreaming develops.
EA-General. Hobbs: Greenland-Svalbard
BIBLIOGRAPHY
1. Nordenskiöld, Adolf Erik. "
Nordenskiöld's Greenland Expedition,"
Na
ut
^
tu
^
re
, vol.29, 1883-84, pp.10-14, 39-42, 79-81.
2. Mohn, H., and Nansen, F. "Wissenschaftliche Ergebnisse von Dr. F.
Nansen's Durchquerung von Grönland 1888,"
Pet.Mit.,Ergänzungs–
band
, No.105, 1892, p.46.
3. Peary, Robert E. "Journeys in North Greenland,"
Geog.Jour
., vol.11,
pp.233-234, 1898.
4. ----.
Ibid
., p.234.
5. Wegener, Alfred. "Meteorologische Terminbeobachtungen am Denmark-shavn,"
Med. om Grönl
., vol.42, pp.129-355, 1911.
6. Rink, Hinrich.
Danish Greenland, its people and its products
, London,
H.S. King, 1877, p.468.
7. Hobbs, W.H.
Proc
. Amer. Philos. Soc., vol.49, pp.57-129, 1910;
Z. Gletscherk
., vol.5, pp.87-122, 1910;
Characteristics of
Existing Glaciers
, New York, Macmillan, 1911.
8. De Quervain, Alfred.
Quer durchs Grönlandseis, Schweizersche Grönland
–
Expedition 1912-13, München, Reinhardt, 1914.
9. Koch, J.P., and Wegener, Alfred.
Z. Ges. Erdkunde
., Berlin, 1914,
pp.34-50, 51-54;
Med. om Grönl
., vol.75, 1930, 676 p.
10. Rasmussen, Knud.
Ibid.
, vol.51, pp.283-340, 1914.
11. Mikkelsen, Ejnar.
Ibid.
,
[:
]
vol. 52, 1922.
12. Rasmussen, Knud.
Ibid.
, vol.57, 1927.
13. Koch, Lauge.
Ibid
., vols. 70, 1927 and 130, 1940.
14. Hobbs, W.H.,
The glacial anticyclones, the poles of the atmospheric
circulation.
New York, Macmillan, 1926, ill.
15.
Reports
of the Greenland Expeditions of the University of Michigan,
Pts. I and II, Ann Arbor and London, 1931 and 1941.
16. Wegener, Alfred.
Z. Ges Erkunde
, Berlin, 1930, No.3-4, pp.81-129.
17. ----. "Denkschrift über Inland Eis - Expedition nach Grönland,"
Deutsche Forschung,
Arbeit Notgemeinschaft Deutsch.
Wissenschaft, vol.2, 1928, pp.196-197.
18. Mirrless, S.T.A. Meteorol. Office,
Geophysical Memoirs
, No.61, pp.36-61,
1934.
EA-General. Hobbs: Greenland-Svalbard
19. Georgi, Johannes. "Greenland as a switch for cyclones,"
Geog.Jour
.,
vol.81, pp.344-352, 1933.
20. Belknap, Ralph L.
Reports
of the Greenland Expedition of the University
of Michigan, pt. II, Ann Arbor-London, 1941, pp.184-197.
21. Holzapfel, Rupert, and Kopp, Walter.
Wissenschaftliche
Ergebnisse
der Deutschen Grönland-Expedition Alfred Wegener 1929
u. 1930-31, vol.4, no.2, pp.246-314, 1939.
22. Wegener, Kurt.
Ibid.
, vol.5, p.30.
23. ----.
Ibid.
, p.31.
24. Georgi, J.
Ibid
., vol.4, no.1, chart at end.
25. Mirrlees, S.T.A. Meteor. Office,
Geophysical Memoirs
, No.61, pp.36-61,
1934.
26. Wegener, Kurt.
Wiss.
Ergeb. d. Deutsch. Grönland-Expedition Alfred
Wegener, vol.7, p.28.
William H. Hobbs