knocker
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Posts posted by knocker
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The police search for a gang of vandals has been call off when it was discovered that squirrels were the culprits. It is understood that the Wiltshire police are setting up a special squirrel unit and have warned the public not to approach as they may be dangerous.
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There was one event that overshadowed all others and will forever be remembered in the tiny fishing village of Mousehole. It was the loss of the Penlee lifeboat, the Solomon Browne, with all eight of the crew whilst attempting to rescue eight people from the stricken coaster the Union Star in hurricane force winds and mountainous seas. I won't add anything here as the events deserve more detailed analysis and I need to look at the official report from the enquiry so I'll hopefully post it as a separate thread shortly. Just to say as a story of skill and bravery it surely cannot be surpassed although of course the history of the RNLI is full of these.
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My understanding is the other way round in that low cloud cover gives a negative feedback in that it reflects above whereas high cloud acts as a positive feedback. Taking the cosmic ray stance that it can influence cloud formation then as we are now in a period of low solar activity which allows greater cosmic ray penetration of the atmosphere this is increasing low cloud formation and thus with a negative feedback will lead to a cooling.
You are quite right jonboy, I've got it the wrong way round.
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Was that 31cm actually in Shrewsbury town centre, or Shawbury? That 8 miles can make a big difference, witness Feb 1996 when Shawbury reported 13cm yet Shrewsbury had only 6.
I don't quite remember Dec 1981 (earliest dateable vague weather memory is July 1983) but I'd happily take a repeat of that month, especially if that 31cm in Shrewsbury was genuine (providing the rest of the Midlands didn't have 70cm). Dec 1990 wasn't bad here -about 15-20cm on the 8th- but it only lasted a couple of days.
Don't know about the town centre but it was Shrewsbury.
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Mind, hail about 4cm in diameter was reported at Crewkerne on the 14th. I know, Somerset not Devon.
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How long do the swallows hang around for? There's a chill in the air but I've been watching a group of 10-20 darting about over the sky here this afternoon.
I also saw some geese.
As far as I'm aware (and I'm certainly no expert) they should have gone last month on the short hop to Africa.Just had a quick loook on the web and it appears a few stragglers may hang around into October.
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Working from home is all very well in the sense that you can probably afford the heating bills but it seems four million of the poorest pensioners look set to lose two thirds of their cold weather payments. The government has set the emergency weekly payments for pensioners at £8.50 a week for this winter rather than the £25 they received in the past two years. I imagine many wouldn't survive that severe cold.
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I'll hold my hand up and say a big YES PLEASE to a repeat.
I'm afraid there is no hope for you jethro. And a young farmer to boot.
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I'm not getting embroiled in this thread but this cannot pass without refutation. Perhaps before launching such ill-informed diatribe against three friends of mine, whose combined and individual expertise I and others greatly value as colleagues, perhaps you might read - for sake of one example - John's biography and then come back here and re-attest that he (or Matt, or Liam) "...haven't got a bloody clue". Do you really think that a 2 minute TV weathercast is a full, academic symposia-style reflection of the (outstanding) professional scientific expertise of someone like John (et al.)?
One additional broader point of clarification: those of you who have actually read the quotes cited in various newsmedia sources on this story today will, I am sure, have already deduced how there is a clear and important distinction to draw between a Met Office internal HR process, versus any undertaken directly by the BBC.
Ian.
I am also not going to get embroiled in this thread but just to say I agree completely with your post. Bit concerned that you are a long term Lewis Hamilton fan though.
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Surely no one in their right mind would want a repeat of this December. Fortunately I missed most of it whilst enjoying the balmy climate of the N. Atlantic. Anyone any memories of this or even comparable Decembers? I expect this has been posted before, if so, apologies for the repetition.
Temperature
Generally. this was the coldest December since 1874 or 1878 in the north and since 1890 in the south, mean temperatures being 5 °C or more below average at some places in Scotland and central England. But in the Channel Islands, Cornwall and parts of Devon. where mean temperatures were less than 2 °C below normal.
December 1976 was colder while that of 1950 was also colder than this at most places in the extreme south and west of the United Kingdom. After a brief mild spell early in the month. the temperature reaching 15.0â€C at Dyce, Aberdeen early on the 3rd. all districts became very cold from the north by the 8th. Although the extreme south and west had near-normal temperatures at times it was the 28th before milder weather extended northwards to all parts.
Frost was very severe and continuous at times, especially around mid-month over inland central and northern areas. Temperatures of below -20 °c occurred in some low-lying parts of the western Midlands and North Wales during the night of the 12/13th; at Shawbury (Shropshire) following a minimum of -22.6 C and a maximum of -12.1 C on the 12th, it fell to -25.2 °c. a record low for England and Wales in any month. but one which was to stand for one month only.
Snow
This was the snowiest December generally since 1878 although 1950, in the extreme south and west and 1976, in parts of the north, were snowier. Snowfall was quite heavy with drifting at times, causing considerable disruption to road. rail and air transport particularly on the 8th and 11th in the south, the 13th and 14th over central areas, having turned to rain in the south. and on the 20th and 21st over eastern England and high ground in the north of Britain. Accumulations of snow exceeded 20 cm. particularly in many central and hilly northern areas, and included 26 cm at Heathrow Airport, London on the 11th, 31 cm at Shrewsbury on the 14th, 91 cm in the Pennines above Hawes (North Yorkshire) on the 14th, 25cm at Poolewe (Highland Region) on the 18th and 33 cm at Lincoln on the 22nd. As a consequence hospitals were kept busy with hundreds of broken limbs, many sporting fixtures were cancelled or postponed while severe losses to wildlife were reported to include rare species such as the Dartford Warbler. But in the extreme south and south-west there was little snow and a general thaw spread northwards late in the month.
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Perhaps we shouldn’t rush to snap judgments. (i know, showing my naivity here)
- The Atlantic Heat Conveyor (within which the Gulf Stream plays a role) helps to maintain relatively mild temperatures in north-west Europe. Some observations suggest that the Atlantic Heat Conveyor has reduced in strength by up to 30% since the early 1990s. More data are needed to distinguish this trend from natural variability, which has recently been shown to be large on a day-to-day basis.
- It is very likely that the Atlantic Heat Conveyor will slow during this century, but not sufficiently to completely offset warming across the UK.
- There is considered to be less than a 10% chance of a collapse of the Atlantic Heat Conveyor this century.
You can download the review.
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There is bound to be a lag time of the effect of La Nina on atmospheric cooling. However it is the feedback mechanism of fresh water melt from the ice shelves of the polar ice caps that may throw a spanner in the works for the GW protaganists.
1. Cool water increases photoplankton and photosynethising bacteria, and it is this CO2 sink that interests me greatly.
2. Flooding of cold fresh water in relatively warm oceans decreases salinity and can possibly cause quite large scale oceanic circulatory change.... we dont know extactly what yet.
3.Increase in cloud cover, caused by an increase in evaporation, due to higher glbal temps may actually decrease the amount of solar radiation reaching the earths surface as it is refleced back into space. There is of course the insulating blanket theory which would work for a few years before eventually heat loss would be greater than heat gain.
I agree that point one is an interesting area that brings in the carbon cycle and ocean and atmospheric regulation. A couple of quick observations on the subject.
The absorption of CO2 by the oceans is greatest where the water is rich in organic matter or where it is cold. Thus the oceans are capable of regulating atmospheric CO2, of changing the greenhouse effect, and of contributing to climate change. The most important aspect of the carbon cycle linking atmosphere and ocean is the difference between the partial pressure of CO2 in the lower atmosphere and that in the upper oceanic layer. This results in atmospheric CO2 being dissolved in the oceans and in some of this being subsequently converted into particulate carbon, mainly through the agency of plankton, ultimately sinking to form carbon-rich deposits in the deep ocean as part of a cycle lasting hundreds of years. Thus two of the major effects of ocean surface warming would be to increase its CO2 equilibrium partial pressure and to decrease the abundance of plankton. Both of these effects would tend to decrease the oceanic uptake of CO2 and therefore to increase its atmospheric concentration, thereby producing a positive feedback (i.e. enhancing) effect on global warming. However, the operation of the atmosphere-ocean system is sufficiently complex that, for example, global warming may so increase oceanic convective mixing that the resulting imports of cooler water and plankton into the surface layers might exert a brake (i.e. negative feedback) on the system warming. The point you were making unless I've picked you up incorrectly.
Regarding increased cloud cover a couple of observations from my somewhat limited reading on the subject. It seems to depend on the level of the increased cloud cover. Increased low cloud will give a positive feedback regarding AGW and increases in medium and high cloud the reverse. And then you have the cosmic ray influence on which subject there seems to be complete disagreement. That being the case, what chance have the lower orders (good old Jane) such as myself got of getting to grips with it?
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How quickly does the atmosphere register changes in ocean temperatures?
Depends whether you are talking regionally or globally. If the former we can bump this up to the GS thread.
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I think some people on here are confusing the Gulf Stream with the the Gulf Stream Drift/North Atlantic drift.
As far as I know the Gulf Stream is the result of the NE and SE Trade Winds in the equatorial region pushing the surface water into the southern part of the Gulf of Mexico along the S American coast. This water has to go somewhere and escapes from the GoM between Florida and Cuba forming the Gulf Stream. This is unlikely to fail while the Trade Winds continue to blow although it could be interesting to speculate what might happen if sea level rises and large parts Florida are submerged.
Once in the Atlantic the Gulf Stream dissipates and becomes the "Drift" which I imagine is influenced by the prevailing winds and other ocean currents. I seem to recall from my O Level geography days in the 1960's that in the Ice Age the Gulf Stream Drift went towards Spain but I don't recall seeing any evidence to support that although it seems a logical conclusion that it certainly didn't come this way.
I can agree with most of that but just to add a little.
With the trade winds blowing westward across the oceans in tropical latitudes and prevailing westerlies blowing eastward at higher latitudes, it is understandable why the current gyres should form the dominant surface current pattern in the low and midlatitudes. What isn’t so obvious, however, is the reason why these currents should be so swift and narrow along the oceans’ western boundaries. What could possibly cause this western intensification of surface currents?
The Gulf Stream is just one of these swift narrow western boundary currents. A look at the diagram shows that there are similar intensified boundary currents along the western edges of all oceans, in both hemispheres. From considerations of the winds alone, you should think that each current could be half an ocean wide. But they are not, so are why they are so swift and narrow, and why do they occur on the western ocean margins only.
There are three related processes that contribute to the creation of strong narrow western boundary currents, all of which are products of the Earth’s rotation and atmospheric circulation. The first cause is that when an equatorial surface current runs into the continent on the ocean’s western margin, it “squirts out the sides, just like water in a stream that strikes a rock, or water from a garden hose that strikes the side of a building.
Second, the Coriolis deflection is stronger in the portion of the gyres at higher latitudes, where these eastward-flowing waters are deflected toward the equator. This pinches the equatorial currents and tends to prevent them from leaving the equator until they reach the very western end.
The fact that the strength of the Coriolis deflection increases at higher latitudes produces another related effect. When this water is flowing east, it gets deflected quickly toward the equator, whereas when it is flowing west, it is very close to the equator and gets deflected only very weakly. Consequently, the water tends to flow farther to the west than toward the east in any complete cycle, and the gyre tends to move westward across the ocean each time the water flows around it. This westward tendency forces the gyre up against the western margins where the currents are correspondingly compressed and intensified.
The third cause of the intensified western boundary currents is also related to the earth’s rotation, through the apparent change in the rotational state of objects moving north or south along the Earth’s surface.
A mass of water starting on the equator with no spin at all appears to acquire a spin as it goes. The farther poleward it goes, the faster it appears to spin. At intermediate latitudes, this amount of spin is less than one complete revolution per day. But if the water mass is wide, it doesn’t have to spin very rapidly for the outer regions to have high speeds. For example, a water mass 1000 kilometers wide and spinning only half a revolution per day would have to move at 65 kilometers per hour on its outer boundary!
Because of the dominant wind-induced current gyres, surface waters in the western portions of all oceans are traveling away from the equator. As these water masses go toward the pole, they acquire the appropriate spin (clockwise in the Northern Hemisphere and counter clockwise in the Southern Hemisphere) to make the current on the very western edge extremely swift.
Taking all of that into account I suspect although the GS may well vary in intensity over periods it is certainly not a cause for alarm. The NAC is another kettle of fish. The flow is weaker anyway and if the atmospheric western circulation in those latitudes suffered sustained spells of disruption then possibly this and the coriolis could severely slow it down. But this is just a guess.
Large scale surface currents. (Source: Keith Stowe-Exploring Ocean Science)
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Who knows when (approximately) the Nottingham/Watnall sounding station started to use the Vaisala sonde RS80 and may be also which sonde they used before? Thank you!
I need to give this some thought but it was after the introduction of the Vaisala automatic sonde station was introduced if I remember correctly. That meant, within reason, you could have the station where you wanted it. So I would say around the late 90s. They would have used the RS80 from the start. The sonde before that that was the Mark 11 that was designed and built by the Met. Office over a period of about 14 years!!!! Quite accurate, very large, very awkward to use and a nightmare in rough conditions. It was replaced by the RS80 at all sonde stations in the early 90s if memory serves correctly.
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A study from 2006.
An international effort to determine the variability of recent snowfall over Antarctica shows that there has been no real increase in precipitation over the southernmost continent in the last half-century.
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Perhaps it's all an illusion. Or perhaps not.
http://news.discovery.com/earth/antarctic-sea-ice-growth.html
http://www.sciencedaily.com/releases/2009/04/090421101629.htm
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Just to add a little detail to my somewhat cryptic post. In recent years there have been a number of research projects to attempt to gain a better understanding of the dynamics of the stratosphere in the arctic. One was “Observations of vertically thick polar stratospheric clouds and record low temperatures in the arctic vortex†by Rigel Kivi and Esko Kyrö. During the period of the research a regular radiosonde measured a record low temperature of -96C at 25.2km and the temperature dropped 23C in just 4km. The reasons for high-amplitude stratospheric temperature fluctuations are somewhat beyond me but here is a link to the paper.
http://www.pa.op.dlr...apers/rigel.pdf
Of course in general the comment that the stratosphere gradually gets warmer is essentially correct; increasingly so above 30km. I remember some years ago we regularly used to fly high altitude radiosondes as part of the normal programme. These used to reach 5mb and above and even touch 40km. On one occasion we actually measured plus temperatures for a couple of days around about 4mb if I remember correctly. I believe not that common at that height. Gave a new meaning to the term “two freezing levelsâ€.
And of course the sonde would sometimes pass through two jet streams blowing in the same direction, the stratospheric jet, at about 30km, being westerly in winter. We followed one down on the radar once and it landed in the North Sea! A tidy step from Camborne.
Off now to put the violin away.
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I think that should read diabatic cooling and warming as from what I have read on the composition and structure
of the stratosphere the stratosphere is stably stratified and any heating or cooling is added or taken away and not
introduced via compression or expansion with altitude.
Below is a better explanation.
Static Stability -- Because temperature increases with altitude in the stratosphere, warmer air overlays colder air.
This is not always the case. See for example midnight sounding from Camborne.And some cooling is much greater than that.
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That's a fair old depression forecast south west of South Island on the 16th. If I read it correctly 930mb.
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Extended solar minimum linked to changes in Sun’s conveyor belt
A new analysis of the unusually long solar cycle that ended in 2008 suggests that one reason for the long cycle could be a stretching of the Sun’s conveyor belt, a current of plasma that circulates between the Sun’s equator and its poles. The results should help scientists better understand the factors controlling the timing of solar cycles and could lead to better predictions.
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I’ve been spending a bit of time trying to come to grips with some of the methodology regarding LRFs as explained by some of the very knowledgeable people that post on this forum. In particular the part played by the warming/cooling of the stratosphere (ozone) by variations of uv radiation during the eleven year solar cycle. This causes (if I’m reading this correctly) spatial variations in the stratospheric wind and also perturbations in the tropospheric circulation and thus weather patterns that can, with experience be incorporated into an LRF. What I appear to have missed is atmosphere – ocean interactions that also accompany this variation.
Whilst looking into this I came across a paper from 2009, “Scientists Uncover Solar Cycle, Stratosphere, and Ocean Connectionsâ€. I don’t know whether this been posted and discussed before, if so apologies, but am I thinking along the right lines in this matter because the solar cycle isn’t a precise science in seasonal terms? The paper can be found at:
http://www.ucar.edu/...solarcycle2.jsp
Also GW is causing the stratosphere to cool, particularly around the North Pole, thus inhibiting ozone concentrations due to the increase of polar stratospheric clouds that cause ozone depletion. Although presumably this is not really relevant as we are talking about equatorial ozone except it will be a positive feedback.
Am I going in the right direction here?
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Britain tilts at floating windmills. I can see Cornwall and Devon srrounded by the blasted things.
A group of companies has come up with a radical proposal that it claims will open up thousands of kilometres of coastline to zero-carbon power: floating windmills.
Project Deepwater was launched last year by firms including BAE Systems, the defence giant, and the utility EDF Energy to research ways of overcoming the engineering problems that limit offshore turbines to water depths of 40 metres or less.
That is not a problem in the shallow North Sea but it is in the much deeper waters off Britain’s west coast, where winds are stronger.
http://www.thesundaytimes.co.uk/sto/business/energy_and_environment/article415396.ece
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With differing information you just don't know what or who to believe nowadays!
Well I don't have a problem with the USGS report. If we are talking world glaciers then I wouldn't look further than here.
http://www.grid.unep.ch/glaciers/pdfs/5.pdf
The full report (someone posted this link in another thread the other day)
http://www.grid.unep.ch/glaciers/
Or even.
Thanks for pointing that out.
War And Peace! And The Weather
in Historic Weather
Posted
At the beginning of the Eighty Years' War against the rule of the Spanish Hapsburgs ice proved the salvation of the Dutch. During the siege of Haarlem in the winter of 1572-3 the city was provisioned almost uninterruptedly for weeks on end using sleighs that crossed the frozen Haarlemmermeer from Sassenheim, where the Prince of Orange was encamped. The death knell sounded for Haarlem when the ice finally melted after 17 weeks, and on 13th July 1573 it finally fell to the Spanish.