The Mild Winter of 2007
According the the KNMI, there were three reasons why this winter has been so abnormally warm. The conclusions of the article can be found below
The winter temperature is more variable than the temperature in other seasons in most of Europe. The record mild winter of 2006/07 has been caused mainly by predominantly (south)westerly winds, which brought mild oceanic air to the continent. This raised the temperature by almost 3 degrees in Holland and large parts of eastern Europe in December and January. Global warming has added 0,4°C since 1971-2000 in the Netherlands (1°C since one hundred years ago). In Denmark persistence from the high November temperatuers also played a role. Together these factors explain most of the anonamously high temperatures.
The probability of these circulation patterns is fairly low if we assume that the wind climate does not change, less than once in 100 years in the Netherlands. However, over the last 30 years there seems to have been a systematic shift towards more southwesterly wind directions. This is associated with a trend towards higher air pressure in the Mediterranean area. The same pattern of air pressure increases is simulated by most of the climate modles that were selected for the KNMI '06 scenarios. However, the modelled increase in air pressure is weaker than the observed increase. The difference can be due to random fluctuations in the weather, but also indicates that we do not yet understand the reaction of the atmospheric circulation to global warming, both from a theoretical and from an observational point of view. The KNMI has therefore constructed scenarios both without much changes in circulation (G and W) and with more westerlies in winter (G+ and W+).
[align=right]Source: KNMI [/align]
, roll on winter......