960 POLAR METEOROLOGY 
It is noteworthy that Burbidge obtained these results 
before reconnaissance had proved them beyond all 
doubt, thus demonstrating the value of careful meteoro- 
logical analysis. His findings are quite what one would 
expect, but it was not until 1949 that they were proved 
or even suspected by many. 
A similar result was obtained by Hare and Mont- 
gomery in a climatological analysis [20]. They showed 
that conspicuous gulfs of warmth characterise the win- 
ter mean air temperature maps in areas where open 
water persists. Three such gulfs were noted in the 
North American Arctic: 
1. Along the east shore of Baffin Bay, where con- 
siderable open water persists in the warm West Green- 
land Current as far north as latitude 70°N. 
2. Along Hudson Strait, where high tidal range and 
exposure to storms keep the pack ice well broken 
throughout winter. 
3. Over eastern Hudson Bay. This gulf was visible, 
however, only until December, after which it vanished. 
The authors therefore assumed with Burbidge that 
the Bay was entirely frozen over by the new year. 
Diagrams (a)—(d) in Fig. 2 show mean temperature over 
the Bay from November to February. The conspicu- 
ous gulf of warmth on the November (a) and Decem- 
ber (b) maps vanishes in January. 
The reconnaissance flights in the winter of 1949-50 
showed that in that year the freeze-up began along 
the northern and western flanks of the Bay; by No- 
vember 22, 1949, continuous though thin ice extended 
as far south as Portland Promontory on the east coast 
and beyond Churchill on the west. The last area to 
freeze (in late December) was south and east of the 
Belcher Islands. 
Other Seas in the American Arctic. In several other 
areas problems comparable with those of Hudson Bay 
are awaiting solution by similar methods. By direct 
reconnaissance, by meteorological inference, or by the 
observation of climatological anomalies, it will shortly 
be possible to achieve greater precision in our ideas 
about their winter ice cover. 
Outstanding among these problem areas is Baffin 
Bay, and its narrow link with the Labrador Sea, Davis 
Strait. Its winter ice cover comprises three components: 
(1) fast ice forming along the shores and in the fjords 
of Baffin Land and of Greenland north of Holstems- 
borg; (2) the central pack ice, composed of heavy 
arctic ice from Lancaster, Jones, and Smith Sounds, 
together with locally formed floes; the whole mass 
drifts southwards on the Canadian Current, ultimately 
discharging ito the Labrador Current, which in turn 
may carry it to the Grand Banks late in the season; 
and (3) the Storis, a drift of heavy arctic ice from the 
East Greenland Current; roundmg Cape Farewell in 
January, it advances northwards in the West Green- 
land Current, reaching farthest north (about 63°-64°N) 
between April and June. 
It has already been mentioned that open water tends. 
to persist through most of the winter between the 
central pack and the fast ice of Greenland (see p. 
959). This break extends at least as far north as 70°N 
at most times. Furthermore, the central pack rarely 
approaches the Greenland coast south of Holsteins- 
borg, and probably never makes lasting contact with 
the Storis. The lane of open water up West Greenland, 
then, must extend without a break from the Labrador 
Sea. Small wonder that the climate of the West Green- 
land coast is so remarkably mild in winter. Disko Island, 
for example, is some 25F (14C) warmer than the 
Baffin Land coast. See curve (e) in Fig. 2 
However confidently these claims are made, one 
should remember the extent to which they depend on 
inference. The open water off the Greenland coast has 
never been precisely mapped. The warming effect of 
subsidence from the icecap to the east, seemingly re- 
quired by the mean winter pressure distribution, may 
also contribute to the warmth of the West Greenland 
coast. The tendency for warm maritime polar air to 
travel northwards along the Bay may be yet another 
factor. A general study of the circulation over Baffin 
Bay, with an associated survey of ice conditions by 
aerial reconnaissance, has much to offer the arctic 
climatologist. 
An area of special interest lies at the northwest corner 
of the Bay near the entrance to Smith, Jones, and 
Lancaster Sounds. This area is the celebrated ‘North 
Water,” a region free of ice and with quite warm sur- 
face waters during the navigation season. It is believed 
to remain partially unfrozen during the winter [34], 
and it is well known that Lancaster Sound never freezes 
solidly from shore to shore. Stations on Devon Island 
(Dundas Harbour), Baffin (Arctic Bay), and Bellot 
Strait (Fort Ross) plainly show the warming influence 
of open water throughout the winter [20, Part I]. The 
North Water must be mapped by aerial reconnaissance 
to determine both its position and its extent far more 
adequately. 
The Scope for Research. Research into the climato- 
logical significance of sea ice has much to offer, being 
still in its infancy as far as North America is concerned. 
The obvious fields for investigation can be summarised 
as follows: 
1. The modification of air masses over ice-covered 
seas is a fertile field for the dynamic meteorologist. 
Since Sverdrup’s careful work on the Maud [54], very 
little has been done on this important subject. Bur- 
bidge’s analysis over Hudson Bay suggests that a thor- 
ough understanding of the mechanics of modification 
may ultimately make it possible to predict both the 
extent and surface characteristics of offshore ice by 
shore-based aerological stations. Quantitative studies 
like those for cP air overland by Wexler [67] and for 
the transformation of cP to mP by Burke [4] and 
Klein [35] are urgently needed for the flow of mtensely 
cold arctic air masses over unfrozen sea surfaces. 
2. The climatological background of the freeze-up 
of the open sea areas also requires investigation, ob- 
viously in conjunction with the foregoing problem. This 
is a task requiring the co-operation of oceanographers. 
Hudson Bay, as a virtually enclosed body of water, 
