18 
Compilation of Summaries 
lantic in November was accompanied by extremely frequent gales and a mas 
sive, directionally stable inflow of mild maritime air from SW. In December Hur- 
rel’s NAO index reached a provisional record low at -2.95. These opposing 
conditions were in line with, at first, drastically reduced, then, enhanced cool 
ing of air temperature. 
2010 (Page 34 et seq.): (JFM) Hurrel’s NAO index for the DJFM period fell to 
a historical low of -2.54, which displayed itself in an unprecedentedly small 
number of gales (4). Both, winter air temperature at Norderney and sea tem 
perature of the GB assumed their lowest levels since 1996. Even so, these 
relative minima exceeded those of the winter of 1996 by 2 K. (AMJ) The ANW 
general circulation entailed directionally stable cold air transports across the 
North Sea on the one hand, and a surplus of global radiation in high pressure 
weather on the other. Just as in winter, quarterly means of air and sea tem 
perature undercut climatological normals no more than slightly, but were at 
their lowest levels since 1996 all the same. (JAS) Repercussions of a long-lived 
omega block over Belarus in July were limited to the southeastern North Sea. 
The North Sea proper firstly governed by SW-erly flow fell under the influence 
of the succeeding trough from the 3 rd decade. Consequently, weather type C 
not only reached a record frequency of 11 days in August, but also dominated 
the monthly sea level pressure distribution, classified as CW. A significant sur 
plus in global radiation in July made air temperature at Norderney climb to its 
3 rd highest level, from which it dropped back to normal in August. (SON) Be 
coming increasingly negative in the course of the last quarter, the state of the 
NAO culminated at -3.56 in December, thus undercutting the record negative 
deflection set exactly one year before. As in the previous winter, the southward 
shift of the polar front brought about an abundance of E weather types together 
with a dearth of gales (6). Fall temperature at Norderney fell to the record low 
of 1993 (5.1 °C). At -5.0 K, the sharp descent in GB temperature from Novem 
ber to December almost equaled the record cooling rate of 1978 (-5.1 K). 
2011 (Page 36 et seq.): (JFM) For the first time in 16 months, the NAO re 
sumed a steady, positive phase in February. Advection of mild maritime air 
from WSW in winter was disrupted but episodically through cold air transports 
from NNW and SSE. Air temperature at Norderney, usually assuming its sea 
sonal minimum in January, returned to normal through an unparalleled ascent 
of 3.3 К in this month, thence following climatology until the end of winter. 
(AMJ) The sea level pressure distribution in April presented itself as a superpo 
sition of the winter and the summer pattern of the positive mode of the NAO, 
thus resembling those of July 2006 and 2013, which went along with extreme 
heat waves. At 10.6 °C, air temperature reached its highest level after 2007, 
while sea temperature performed an unprecedented jump of 4.1 К to 7.6 °C. 
Though vigorous WSW-erly winds caused a marked flattening in further sea 
sonal ascent, spring temperature was higher at Norderney in 2007, only. (JAS) 
The joint frequency for July and August of high pressure weather types (A) 
reached a record low of 6 days, while low pressure weather types (C) at 19 
days were never more abundant. This spell of unsteady weather came to an 
end in September through a vigorous and directionally stable flow from WSW 
that took on anticyclonic characteristics past mid-month. Due to substantial 
deficits in global radiation in midsummer and, conversely, a strong surplus in 
September air temperature evolved sideways, stagnating at the climatological 
seasonal mean level of 16.2 °C. (OND) A long-lived (10/22-11/23) blocking ep 
isode caused a directionally stable S-erly flow, delimited from two sustained