Cooling the seas, cools the winters
Thesis
The North and the Baltic Sea usually guarantee
Northern Europe a moderate winter climate. The heat stored during the
summer season is usually sufficient to keep the coastal countries under
the influence of maritime climate. Only four months of a war at sea
staged predominantly in the Baltic and North Sea in autumn 1939 brought
a cooling that was sufficient to prevent the seas from playing their
common role in the first war winter 1939/40.
Facts
Within a short time at war ten thousands of sea mines
had been laid in the southern part of the North and Baltic Sea. The sea
was stirred and turned about by massive naval activities, and exploding
shells, bombs and mines. This happened in waters which are able to
store hardly more heat than for one winter season. Any early loss of
heat has inevitable consequences during the time the sun’s influence is
diminished. During autumn 1939 the regional winds deviated
significantly from climate data toward northeasterly direction. Hamburg
which is in so far representative for a wider region observed only
one-third of south-west winds, but more than the double of
north-easterly winds than normal.
At Helgoland Station the water temperatures taken indicate that an
unusual deviation had taken place in October and November 1939.
However, a sufficient number of reliable water temperature measurements
are not available. In mid December 1939 sea icing started early. The
drop to extreme low temperatures came in early January 1940. An
unexpected and unusual second cold wave in February was particularly
obvious in the Southern Baltic Sea and Helgoland Bight. In Northern
Germany, which was closest to the major early naval activities in late
1939, observed the coldest conditions for 100 years.
Evidence
The primary proof of cooling can be derived from the
diversion of wind from average in autumn 1939. The wind blew from the
land masses towards the southern Baltic and North Sea, to those sea
areas that saw the most ‘stir and shaken’ of seawater, thereby exposing
warm water to interaction with the atmosphere. Whenever evaporation
takes place, the cooling of the water is included. To stir the hot soup
is the very same process.
Not the date of first icing but the duration of icing are proof of the
‘under cooled’ seawater body. The deeper waters had lost the stored
heat too early and too much to prevent the second cold wave from
settling over Northern Europe once again.
In Great Britain, which is closer to the influence of the Atlantic, the
February did not deviate as much from average as the January 1940, due
to the fact that some water was replaced by the Atlantic current system.
Conclusion and further reading
It is possible to prove that a cooling of the seas
took place, by locating the areas with highest naval activities with
the regions where the greatest air temperature deviation took place,
and by assessing the icing conditions correspondingly. Winter 1939-40 (2_11), and Lost West Drift (2_12), and Sea war events (2_13), and North Sea cooling 1939 (2_16); and Baltic Sea cooling 1939 (2_17).
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