[quote=Steam Fog;292991]I suspect this was posted somewhere in amongst the media thread, but it's relevant here as well (and may not get so quickly buried). http://metofficenews.wordpress.com/2012/02/09/whats-bringing-the-cold-weather-to-europe-and-the-uk/[/quote]
The thing is, that there have been very ordinary humble non professional members of the public who are simply weather enthusiasts on internet boards such as this one and its neighbour board, that made this connection a few years ago, researched it, and started using it in longer term forecasting waaay before the METO did. Its not long ago they were doing seasonal forecasts based on supposition of NAO signatures 6 months ahead in the atlantic ...oh and continuing to mix climate and weather through an irresistable need to bring multi decadal AGW theory into it as well
No coincidence that their extended forecasts have, relatively speaking, improved.
They got badly burned when evidence emphatically showed (the obvious)that HLB for the short season was still possible in the winter of 09/10. I remember a spokesperson from ECMWF interviewed on a Beeb biased AGW programme around 2007 who suggested that winter time HLB was something left back in 1962/63 and made its last dying imprints in the late 70's and 80's. That to me proved that they were using AGW theory rather than looking at cyclical natural forcing patterns such as stratospheric cold/ warm phases as attributed to QBO patterns, ozone, PDO jet stream cycles etc.
In fairness to the METO, what they have written in this link is absolutely correct and very well explained My point is that they have changed their tune for the better, unfortunately because the weather(not the climate) got the better of them
Indeed - but I suspect their error was in placing too much emphasis on AGW effects and not enough on the natural cycles to which you refer. I still think over time that the AGW signature will have an effect but it's difficult to work out regional impacts because of the complex interactions. In the meantime let's make the most of HLBs while they are manifesting themselves.
I'm mindful of not going O/T in terms of the AGW remit but suffice to say that I totally agree with you in terms of where the error lay. The matter of climatic effects, whether they be man made or natural/cyclical on the stratospheric signal or any other, is one which we all have varying views on and is a very interesting topic for the relevant section of the forum
Atmospheric blocking is complex and not fully understood. It is , however clear that it is due to the interaction of tropospheric waves with the stratosphere. In this the vertical disctribution of temperature plays a key role. A very cold polar stratosphere which is encouraged by ozone depletion and CO2 increase favours a strong high latitude jet. Solay UV, CFCs polar stratospheric clouds, all play a role in regulating stratospheric ozone
Atmospheric blocking is complex and not fully understood. It is , however clear that it is due to the interaction of tropospheric waves with the stratosphere.
All blocking or just that helped by SSW's and stratosphere changes?
I've a lot to learn, as ever, but I thought the tropopause 'puts a lid on weather' as temperatures rise from there up? So, how does stratosphere 'weather' (and we mean 'weather', not energy because the stratosphere is very rarified and contains a tiny fraction of the air the troposphere does?) higher up feed down through the tropopause, given how little of substance there is to the stratophere, and have such a apparently major effect?
The effects of the solar cycles on stratospheric cycle and ozone are much more demonstrably proven than any effects of CO2 are. We saw in winter 09/10 and also once again into the start of the following winter how low solar mimimum activity substantially boosted ozone, made the stratosphere anomalously warm and hence led to a record breaking -AO and HLB
I think you are over simplifying there. The work at Reading University and Imperial College suggests a link between solar UV and high latitiude blocking but the link, whilst it is significant is not very strong, there are clearly other factors playing an important role too. The role of CO2 in causing stratospheric cooling is as well established as is the role of ozone, the physics is very similar. The influence of solar UV is through its regulation of ozone concentrations. I'll list some of the key papers on atmospheric blocking later
Probably best continued on the climate threads so the shorter term day to day stratosphere observations and possible implications on tropospheric weather patterns can carry on here. I say that because I think the mods indicated that is what they wanted It also means that the subject can be responded to more leisurely and when individual time allows.
Edited by user 17 February 2012 12:51:07(UTC) | Reason: Not specified
It does put a lid on active weather largely because very little water vapour gets into the stratosphere but it has become apparent over the last 20 years that changes to lower stratopsheric flow do have a major impact on tropospheric weather patterns. This is partly radiatively induced through the interaction of sun with ozone and partly through the interaction of tropospheric waves. I get the impression though that we aren't meant to discuss the science in this thread so I will stop there. It is fascinating though and heas led to a marked improvement in the ability to predict blocking episodes.
Edited by user 17 February 2012 13:06:28(UTC) | Reason: Not specified
I'll list some of the key papers on atmospheric blocking later
Please do. Either here or in climate section, whichever you think more appropriate.
Here is a paper which is freely available by Brian Hoskins and a student it shows how the ecmwf ensemble suit is able to predict the onset of blocking about 10 days ahead, some interesting insights and freely available but a bit technical.
http://onlinelibrary.wiley.com/doi/10.1256/qj.01.173/pdf.
Edited by user 19 February 2012 22:04:01(UTC) | Reason: Not specified
I think the big disappointment underlined by the model output is echoed by the big cool off in the stratosphere, which is quite opposite I will admit to what was expected after that promising warming during January. It offers the unpalatable prospect of something like 2007 all over again with an abnormally warm Spring followed by an awful disturbed summer as a sudden final warming arrives late and blocking no doubt will finally arrive at completely the wrong time to send lows across the UK by June with all the disruptive downpours that implies
Drought there may be, but come August people will be ruuing they prayed for rain
Here's a very early stratospheric warming event that was reported on that I have. This report was written in 1952 about a stratospheric warming event during February 1951
Pressure pattern about time of the warming
And about 4 weeks laterThe report also mentions a warming event towards the end of February 1952, the pressure pattern from 24th February 1952
About 4 to 5 weeks later
Edited by user 21 February 2012 11:33:47(UTC) | Reason: Not specified
Cheers Kev , an interesting post
Rather out of idle curiosity rather than anything else.
http://images.meteociel.fr/im/5137/gfsnh-10-360_vsn9.png