It's been a while since I've been on, but things have become busy. I've gradually been working on a theory of what influences temperature and other weather conditions during winter in Britain and Ireland. Below is a hurried presentation of this theory. Following on from this is a brief discussion of the possible implications for this winter, and the observations made on the year so far which may be of relevance to the said winter. This shouldn't be considered a forecast, however, and I'm going to such lengths to discuss the theory so that anyone who's inclined to read the details of said theory can reach their own conclusions.
From the evidence, it seems to me, and I would hope to anyone else as well, that the following are major players in our winters (determining how cold and/ or snowy they are, in part or whole):
Absolute strength of the solar wind, as of several years ago to about two decades ago.
Relative strength, over the same time period as above. In other words, the “rate of change” in solar wind strength.
The location where Northern blocks set- up, which may be determined by Sea Surface Temperatures (SST, as commonly abbreviated) in the Atlantic. Such temperatures in the Pacific, of which the PDO (Pacific Decadal Oscillation) is a measure, seem, without taking into account solar activity (as measured not by the misleading sunspot series, but by more reliable 10BE and 14C data), to be rather strongly correlated with the likelihood of a severe winter, but when one considers the radioisotope (10Be and 14C) data, such a strong correlation can be found that the notion of a positive PDO being harmful to the likelihood of a severe winter in Britain and Ireland can be dismissed entirely.
The ability of the Polar Vortex (commonly abbreviated as PV) to stay together. An influencing factor here may be the QBO (Quasi- Biennial Oscillation), which can be considered to be a measure of the strength and direction of the wind in the Stratosphere (a zone in the upper atmosphere) from the tropics to the North Pole.
My failure to take into account the third factor, I currently consider to explain the extreme winter in the US, but the mild winter here, two winters ago.
Now for a presentation of the data, at which point I wish to point out that this is a collection of data from various sources, whose authors do not necessarily at all share my thoughts on the subjects with which these references deal.
Radioisotope data, and firstly, it's important to recognise that there is a “1-2 year (possibly more, possibly less)” delay in deposition of radionuclides on the earth's surface after formation in the upper atmosphere as mentioned here:
http://www.eiscat.rl.ac.uk/Members/mike ... rcsent.pdf .
contains two records, and is taken from separate places in the world. Both are measures of the concentration of the radioisotope Beryllium 10, greater quantities of which are formed in the upper atmosphere (by spallation events) when the Earth's magnetic field is weak, as a weak magnetic field allows more cosmogenic particles (protons, deuterons, alpha particles and and heavier ions) to hit our atmosphere. The field is strengthened by the solar wind, this when the solar wind is weak, more 10BE is created in our atmosphere. Periods of low solar wind (low points in the said charts) correspond nicely with cold winters in Britain. A possible explanation of the mechanism is ionisation caused by the cosmogenic particles, causing cloud seeding, therefore reflectance of light and heat from the sun, but this is by no means proven.
More notable than the tendency for cold winters to occur during periods of low solar activity is their tendency to occur after sudden upswings and sudden downswings in activity. There seems to be a delay of about 22 years. Sudden upswings seem to be associated with cold winters at solar minimum, and downswings with maximum. In a recent study I made involving the CET record, I chose to count the winters since 1659/60, when there has been at least one month of an average temperature below zero degrees Celsius, of which there appear to be 31. I made a note of whether these winters occurred at or within a year of solar maximum or minimum, or at other times, of the temperature of all qualifying months, whether the winters occurred after an upswing or a downswing, or at a time when the solar wind was of otherwise unstable strength. The Central England Temperature (CET) record is available here:
http://www.metoffice.gov.uk/hadobs/hadc ... nload.html
For measurements of the strength of the solar wind, I chose mainly the two charts in reference 1, but where/when these charts disagree, I've used this chart:
, which compares the 10Be data with that of Carbon 14 (14C), another cosmogenic radionuclide. I've chosen whatever state of affairs is backed by two datasets.
It would appear, using the datasets mentioned, that downswings and upswings in the strength of the solar wind over an approximately 22 year period, reliably (without fail) produce winters with at least 1 sub-zero month, and that the bigger the change, the “bigger” the winter. The tendency for cold winters to occur at Solar Maximum after a period of decline, and at minimum after an upswing, is very strong, except when unusually short or long cycles intervene, which by their very nature, shift the position if these points or otherwise alter timing. Also, 30 out of 31 winters featuring a sub- zero month occurred after a decline, upswing, or very extensive fluctuation, in strength of the solar wind.
Unfortunately, I haven't been able to obtain any current radionuclide data, but there are two measures which tie-in very closely with such data, and these are 10.7cm Solar radio flux:
, and Ap index:
, data, the latter being a measure made from the Earth's surface, of the strength of our planet's magnetic field. The radio flux chart indicates that we're currently at 1810 levels at most. A recent calculation:
http://www.sciencedaily.com/releases/20 ... 092955.htm
, reported by the Royal Astronomical Society, suggests that we're currently headed for a downswing in solar activity as deep and protracted as happened during the Maunder Minimum, the birth- pangs of which began around 1605, and which ended around 1720.
Onto the sunspot record, and this is a second- rate measure of solar activity, as there have been numerous changes of counting practice over the centuries, and despite the best efforts of leading researchers, to iron- out these inconsistencies, we may never have a reliable record. However, I use it to find the times of solar maximum and minimum. Interestingly, the time- lag between the latest solar maximum (last year) and the one before that, is also the longest in over 200 years, another important measure of change in solar activity. The record is available here:
note that the record has been recalibrated recently, so is discontinuous with the record which has been used for a very long time, but dates of solar maxima and minima have remained unchanged.
As for the QBO (Quasibiennial Oscillation), which is about wind speed and direction in the upper atmosphere, we have data going back to 1979:
with reconstructed date to about 1945:
http://strat-www.met.fu-berlin.de/labit ... l-2006.pdf ,
http://www.atmos-chem-phys.net/11/11679 ... 9-2011.pdf
.From this data, its clear that of all of the winters since 1945 which have featured at least one month of averaged sub-zero temperatures, namely 1946/47, 1955/56, 1962/63, 1978/79, 1985/86 and 2010/11, all bar 1962/63 [note that the splitting of the vortex in the winter of 1962/63 (January 28, according to one source), came too late to explain the severe winter] have occurred whist the QBO has been in a positive, or Westerly, phase.
Conventional wisdom states that a Westerly QBO helps to keep the polar vortex intact, with the current mantra being “split is what we need”. The evidence, however, speaks for itself, and it may be that a distorted but not split vortex prevents low pressure getting stuck in places unhelpful to cold winters in Britain; fragments of a vortex which has split may be less amenable to shifting. This is not a popular view, but science is supposed to be based on facts, not unproven theories.
So, what of the chances of this winter being particularly cold and / or snowy? My personal opinion:
three out of 4 major requirements are satisfied- we have a very strong downswing in solar activity over the past 20- 25 years, the sun is just past Maximum (the preferred time, given these circumstances), and the QBO is in a positive, or Westerly, phase.
Also, the year so far has produced a lot of Northern Blocking (the past few months, for example, have produced a scenario no less “blocky” than 1962), and there is currently, as there has been for some time, a very strong tripole (a warm, cold, warm, pattern, down the East coast of the US, which is conducive to a buckling in the Jetstream, which tend to produce a negative NAO (North Atlantic Oscillation), which is conducive of cold weather in winter in Britain and Ireland. Missing data to the West of Greenland has obscured the picture until recently, but the strength of the tripole is now apparent:
Moreover, the strength of the downswing compensates for the fact that the solar wind was relatively strong until around 2000- the bigger the downswing or upswing, the bigger the winter, generally.
(1) https://tallbloke.wordpress.com/2011/02 ... -activity/
(2) http://edberry.com/blog/authors/ed-berr ... e-problem/
Take a look at the current and upcoming Winter forecasts or Autumn forecasts and any weather alerts or news.
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