Well, I'm going to take a slightly different perspective.
My background is very much as well as instrumental data and datasets as in climate variability and climate change.
So what I'm going to talk about, first of all, is the contribution of the Ratcliff dataset to Central England temperature.
And centrally in temperature is the longest instrumental data in the world, but it's a composite dataset.
So the Ratcliff is from one station.
Central England is too many stations. It starts in 1659.
And as you heard Tim say, there are no instrumental observations in 1659.
So some of the early data, although it's nominally quantitative, is actually reconstructed from diaries and things like that.
And I won't mention a lot about that, but that's the work of Gordon Manley.
And then finally, I'm going to show you how we can use the Ratcliffe Observatory data even though it's in one station.
This actually slightly surprised me to cause quite a lot of light on the relationship between synoptic
variability in the North Atlantic and temperature and some other parameters at Oxford itself.
So it's so it's more useful than I thought.
So there's the observatory, there is the site which, as Tim said, is a fairly constricted site.
That's probably actually changed quite a lot over time.
And here, just to overlap with Tim's talk is a book of observations from The Observer in March 1773.
The world temperature data in those days, but they're incomplete.
And so the complete data only starts, as Tim says, in 1814, though I daresay some use actually could be made of that earlier data.
That's Gordon Manley. Gordon Manley is very famous in meteorology for the Central England temperature dataset.
This was a tremendous effort over decades.
And in those days, it was before global climate change existed as a viable study.
People many people thought the climate was constant. So Gordon actually pioneered this work as a time when this sort of work wasn't very fashionable.
And we are now very grateful in the days of climate change that he actually did this all those years ago.
He was also president of the World Meteorological Society, and he wrote papers, as you can see on that slide from 1946 up to 1974 on this topic.
The first paper in 1946 didn't include the Radcliffe data,
but Central England temperature tries to represent something like the Midlands, but there aren't enough data in the true Midlands.
So what he did, he took data from the Lancashire region and from the Oxford region and averaged them together to represent the Midlands.
So that's what it is, Central England temperature, but it covers everything from the Lancashire Plains down to down to the Radcliffe Observatory.
Then in 1953, this was the first monthly Central England temperature paper which combined the Lancashire data with the Radcliffe data.
And you can see on that graph, Lancashire and lots of stations there, those, those places are just to give you a geographical perspective.
It's basically the area was to the west of Halifax and Salford between there and the coast, and you can see Oxford.
And so that's the sort of range of Central England temperature.
And this is his most famous paper in 1974, which published the full Central England temperature data from 6959 to 1973,
and the central inland temperature data is quoted and used throughout the whole world.
And I'll show you some very surprising reasons why that might be so light.
At the end of the lecture, it's not only the longest temperature dataset, it's also surprisingly useful in a much wider context.
And thanks to Tim, these are Gordon Manly's original manuscript diagrams showing up summarising what he achieved.
I think these are different seasonal. This is the winter top, spring, summer, autumn and the year.
So don't worry about that because you can see things much more clearly afterwards.
But that is itself a historical document is quite as much as some of the Ratcliff data themselves.
Now one of the problems with the Ratcliff data is that it is subject to urbanisation.
The city has grown. The site has also changed somewhat.
So when the work was done to try and update the Ratcliff work and its application to Central England temperature,
which we did in the Met office, we had to take a very close look at this problem.
We also wanted, if we could, to create a daily central temperature dataset back as far as possible.
This is very valuable for looking at synoptic variability, remembering that the Central England temperature is actually monthly,
even though the Ratcliff Observatory itself has and daily data going back quite a long way.
So we had a lot of difficulty because we couldn't really find the only data back
as far as you want it to go in the Lancashire area and in the Oxford region.
So we use a whole variety of other stations.
You can see some of them in Black Linden, I think that's in Rutland, Cambridge and more recently, more recent years, more Vernon Squires Gate.
And we managed to extend the daily Central England temperature record back to 1772.
But we could only use the Ratcliffe recalled in up to 1973.
So this is the daily central England temperature record from 1772 to 1991.
It's kept up to date. Although Hadley Centre on a daily basis, actually, it's actually updated in real time.
So you can see what's happening. The Central England temperature today.
What happened yesterday, which is very valuable for lots of applications, but we cannot include the Radcliffe data after 1973 and in the later paper,
this is the last paper that was written on Central England temperature in 2005 by David Parker and Brian Holton.
They compared the Ratcliffe Observatory minimum temperatures to the daily Central England temperature minimum temperatures.
Now, when urbanisation takes place, you guys, the heat actually comes partly from the buildings,
but quite a lot of it actually comes from the concrete surfaces, the roads, etc.
And it's the heat released night that actually causes the major problem.
So it's the the night time temperature, the suffers from urbanisation much more than the daytime temperature.
So if you want to detect urbanisation, you should look at the Night-Time temperatures and you can see that the graph is the
reactive observatory relative to the minimum daily central England temperature,
which itself is corrected for some urbanisation.
And you can see a rise of about half a degree since the beginning of the 19th, 20th century, and most of that's taken place since about 1960.
I don't think we fully understand the cause of the shape of that curve.
I think it is quite complicated. Oxford is grown, but I suspect slight changes may contribute.
And so you can see even up to 1973,
Central England temperature probably might have a small amount of uncollected urbanisation, but they tend to be small.
Now what we've done, what I've done next is to look at what these Central England temperature and the Ratcliffe Observatory
temperature records can tell us about climate change actually in central England and at Oxford.
So on the left hand side sky, we will see temperature anomalies, temperature differences from an average over the last 30 years, 1981 to 2010.
And the Central England temperature record is a red and the Ratcliffe Observatory record is is blue.
And these are the annual means of the day and the nights.
And the first thing you can see, if you look at the blue records,
it parallels Central England temperature up to about 1960, and then it overtake and then it catches up with it.
And that's a sign that the Ratcliffe Observatory temperatures have warmed more than the central England temperature, which has little urbanisation.
So and you can see that the amount is several tenths of a degree.
So when you average the minimum and the maximum is probably about.
0.3 degrees. Which shows you that you the maximum temperatures are probably okay.
They probably don't suffer from urbanisation. It's the minimum temperatures.
And you can see the sharp rise in temperature in the last 40 years or so from minus point five relative to 1981 to 2010,
up to about 2.3 degrees above.
So it's been a rise of about 0.8 degrees centigrade in central England, temperature one degree in the Ratcliffe in the last 50 years or so.
And that really is quite strong warming on this 10%.
It's actually had quite a big effect on what people can grow, not only vines.
And there's a magnificent vineyard near where I used to live in the South Chilterns, which produces excellent white wine.
I don't fully recommend some of the red wines produced in Devon.
We had a party one day and it was a bit of a disaster when we bought a very expensive bottle of red wine from a vineyard north of Exeter.
But something else you can grow very well nowadays is maize.
And maize wasn't viable in England till about 30 or 40 years ago because you need most summers to get a good crop to make it financially viable.
And there are papers in that the Met Office have written about this. And so maize is now very much commercially viable, even on the high chilterns.
It was a field literally next to our house, 600 feet above sea level.
Growing maize quite successfully in the 1990s.
2014. Go back. The last point on that graph is 2014, the warmest year.
You can see the Ratcliff just point pokes up as blue above the red slight, slightly warmer.
And there's one of the Ratcliffe observers on the telephone to Radio Oxford on 9:15 a.m.
on the 1st of January 2015 to tell the world what had happened of this great event.
And indeed it was. So we have just had the warmest year on record.
And one of the surprising things about 2014, there were no there were no extreme temperatures.
It was just uniformly warm all the time for a whole variety of reasons, which I haven't got time to go into, but you could ask.
So it's a sign of what might happen in the future.
We don't have to have great extremes that the whole record can just lift up the whole statistical distribution of temperatures.
Countries rise as a whole. You don't need a big change in the extremes, though that may happen as well, but it didn't happen in 2014.
In the top diagram, I show you in blue the rise of minimum temperatures and Ratcliffe and the rise in Central England minimum temperatures.
And again you can see the problem that there is a they were relative to 1981 to
2010 they were pretty well parallel until 1960 and then they join together.
And so we've had a rise in the minimum temperatures and below is the maximum temperatures.
And there you can see Central England and Ratcliffe.
I mean, there's slight differences in detail, but they've gone together essentially.
So the Ratcliffe is a pretty good measure of the way that maximum temperatures have risen in central England.
So it's a very vulnerable record. And in fact,
it's worth pointing out that temperatures in one place are actually very highly correlated with temperatures in another place of the United Kingdom.
So you have to go a long way away from that, from the Ratcliffe Observatory before the temperature changes that you get,
rather than the mean temperatures which vary across the country actually very, very much.
It's not the case. Rainfall is much more complicated.
So the Ratcliffe Observatory record on its own can be surprisingly useful on its own, even though it's one side.
The last thing I want to point out, if I go on to climate variability, is although the Radcliffe Observatory suffers from urban warming.
This could be quite valuable in future because the climate change that the majority
of our population will suffer is the general climate change plus the urban warming.
And there's no work going on in the Met Office to model these effects in detail.
And this will become a big topic, I'm sure, over the next 20 or 30 years.
So if you can correct for very local site changes, the Radcliffe Observatory together with London,
various London records, various other records in big cities, could become especially valuable in its own right.
And the fact it suffers some urbanisation could be a positive advantage.
And that's often not pointed out when these sorts of talks are done.
So there is of the winter and central England is in red, the active observatory is in blue and this is the mean temperature.
So there's a bit of urban warming at the end. First of all, the straight red line is the trend in central England temperature.
And you can see over the last two centuries taking the simplistic view of a straight line, there's been a rise of one degree centigrade.
But what's much more interesting are the wobbles in that curve, and they really their major wobbles over a century.
So if you look at the dip around about 1899, both together, there was a rise up to about 1920.
Then there was a fall until the 1970s and then a rise since then and a bit of a flattening.
So is that chance or is it due to something?
And you can notice at the bottom of that fall is the great winter of 1962, 63, after which the warming restarted.
Why was that? Well, a lot of the cause of that, as I was showing the minute, is weather variability.
Now, the most important weather pattern that exists that affects the United Kingdom in the winter is the North Atlantic oscillation.
The North Atlantic oscillation measures the strength and frequency of the westerly winds that flow from the Atlantic,
from the Atlantic to Western Europe. And in the positive phase, the storms tend to go over into the north of the UK, bringing in westerly winds.
Warmth from the Atlantic over the observatory.
In the negative phase, the storms tend to go into the Mediterranean much more.
We get an increased frequency of easterly winds and this is accounts for about half
of the weather variability that affects Oxford or Wallingford for that matter.
And you can measure it in a very simple way. And this is almost unbelievable.
But if you just take the pressure difference between Iceland and the Azores, that measures it perfectly, almost perfectly.
There are other ways of doing it. So this is a major fluctuation in the atmosphere, and it could be measured very simply.
And we've got data from of these areas going back to the early 19th century.
So how does the Ratcliffe Observatory record compare with the winter North Atlantic Oscillation?
So the winter North Atlantic oscillation strength is measured in red and the Ratcliffe Observatory temperatures are measured in blue.
And what I've done so this is a little trick we do in climatology because they're very different measures of different things.
We've brought them to the same scale. So the variability of both is the same.
This is in the standardisation for the guests here. So we can plot the graphs on the same scale.
And you can see that although towards the end of the curve, the red the blue curve doesn't quite follow the red curve because of global warming.
This is substantial similarity. In fact, the correlation of the winter values, not the smooth curve.
Winter values is 0.71. That's half the variance.
So the North Atlantic oscillation explains half the variance of the Ratcliffe the temperatures in the winter.
And not only that, you'll notice that in fact the warming in the last few decades is not been very great in Central England temperature in the winter.
So the winter actually winter shows the least warming of all the seasons and it's dominated by synoptic variability.
So if you look towards the end of the record, you'll see in central in the winter, North Atlantic Oscillation,
a big, huge negative blob and you'll see in the blue curve a smaller negative blob.
That was the winter of 2010 11.
We had the coldest December since 1890.
Five caused by a negative North Atlantic oscillation almost entirely.
The easterly winds from Russia and Siberia caused that winter, and that's the North Atlantic oscillation.
Then the bottom is a it's a parameter we haven't discussed so far as the wind speed.
This is the relative wind speed. It turns out that in the westerly phase from the Atlantic.
The winds tend to be strong in the easterly phases. When you get high pressure and winds from the east, they tend to be weak.
And you can see the wind through the winds. At the Ratcliffe Observatory, though, it's an open site.
You might think it's not very reliable and we know there may be some problems right at the end.
Follow each other very well. And by the way, these smooth curves are all 22 year running mates.
So that is another indication that the North Atlantic Oscillation actually controls Ratcliffe Observatory winds.
Something that perhaps is not often discussed is of great interest to the
energy industry because as I'm going to show you some new results in a minute,
that they are very much affected by the winds around the British Isles in the winter.
If the turbines don't don't turn, they don't generate much electricity.
So wind turbines are highly sensitive to the winter North Atlantic oscillation when
a lot of electricity is generated because the winds are strongest in the winter.
Now, we've had a very big breakthrough in the last two years in forecasting the winter North Atlantic oscillation.
Until recently, this was thought to be impossible, the winter North Atlantic Oscillation, because it's something in the stormy North Atlantic,
fantastic variability was thought to be completely unpredictable beyond the timescale of weather forecasting.
So we had but that turns out not actually to be true and so on.
On that graph in black is the winter North Atlantic oscillation in this standardised scale and in the in blue that the solid blue line
high costs from the latest climate model of the winter North Atlantic oscillation and all the little blobs are individual members.
We have to run the middle many, many times. And so the the blue is the average and the correlation is is over point six.
And when you get the correlation of over point six, all the all the users start to get interested because such a rough measure of,
of, of the threshold of usefulness to society of a forecast.
So these forecasts are now regarded as useful and this is developing new commercial opportunities for the Met Office.
And this is all published in Geophysical Research Letters in April 2014.
So congrats to the Radcliffe Observatory. Extreme cold months was December 2010.
You can see the scale there. The darker the blue, the colder it was.
And you can see Oxford on the Thames there was just outside the coldest area relative to normal.
These are relative to normal, but it was quite close and the lowest temperature that she was -10.9.
But no, that was nothing like as low as in the great winter of 1947.
The reason for that probably is not so much global warming as a little component of that.
But 1947 had continuous deep snow for a much longer period than December 2010.
Nevertheless, it was the lowest temperature for a long time.
I think for several decades has been record. Ratcliffe And this urbanisation, of course, and this is December 2010.
On the right hand side, there's the snow cover. And you can see Ratcliffe is right in the middle of that snow covered area.
And Cornwall wasn't it wasn't snow covered that might that top picture might have me in that plane.
I was that was a British Airways plane. I think that's the one the last one that landed from San Francisco to London.
And we landed in the blinding snowstorm and the airport was closed 3 minutes later for the next five days.
So those are pretty dramatic introduction to the winter of 2010 for me.
And there's a a Waitrose fan who went a bit too fast in in Devon for the conditions.
And coming on the summer now, this is the Radcliffe Observatory.
June to August temperatures, the mean temperature is in black, the minimum temperatures in blue and the maximum in red.
And you see, again, not as much warming perhaps as you see in the annual mean.
The minimum temperatures and the maximum temperatures have not followed exactly the same course.
This is almost certainly due to atmospheric circulation. I haven't actually looked in great detail so that would bear some some looking at.
Well, we can relate to some extent these values to atmospheric circulation.
Now, in the winter I mentioned the winter North Atlantic oscillation.
In the summer there was a summer North Atlantic oscillation, but it's somewhat different.
In the winter, you can measure the North Atlantic oscillation by the difference in pressure between Iceland and the Azores.
If it's positive, the Azores is high pressure and the Iceland is low pressure in the summer is very much more the UK versus Greenland.
So in the positive phase of the summer, North Atlantic oscillation, all those solid lines,
that's high pressure and cyclonic conditions over the UK to Scandinavia and low pressure over Greenland and it's very strongly
related to rainfall below and you can see the correlation scale on the bottom and you see the colours and the correlations,
that's the negative correlations. So when these anti cyclonic positive, some of those Atlantic oscillation is dry.
So this is a drought pattern and the correlations, negative correlations exceed point six over reasonable sized areas.
Now over the Ratcliff Observatory,
you wouldn't expect the correlations to be so high because at one position you're much more in the hands of individual thunderstorms,
whereas if you average over a region, you know, you average having lots of storms and it it smooth things out.
Nevertheless, we do get quite a good relationship.
This is July and August where we at the moment define the summer North Atlantic oscillation.
The temperature correlation is 0.49, and that is caused by the fact that when the summer North Atlantic isolation is in,
it's positive and it's cyclonic mode, there's lots of sunshine and it's warm.
The rainfall I plotted is as negative of the rainfall just to show how it goes with the some of those to Arctic oscillation.
And the correlation is almost the same, but negative but minus .48.
And the similar situation circles is in in black.
So we can explain rather less of the Ratcliff record by the sum of those, the Atlantic oscillation.
But nevertheless, that's about 25% of the variance rather than 50% of the variance.
This is because summer weather patterns are much more variable than the winter weather patterns.
That may surprise you, but that is the case.
So very recent work that I've done suggests that we can do a better job of the summer North Atlantic Oscillation,
and it might explain a bit more of the variance, but not as much as in the winter.
So extreme warm months, which was a positive phase of the summer, North Atlantic Oscillation and some other weather patterns as well.
You'll probably remember August 2003.
That's when the highest temperature ever recorded in Britain, 38.5 degrees centigrade, when old man it's over 101 degrees Fahrenheit.
So that so that was in Kent and the Ratcliffe didn't get quite to those temperatures where you got to 35.6, which is 96 degrees Fahrenheit.
And you can see the the red blobs are the warmest areas, which were which were over two and a half degrees above normal for that month,
were mainly to the southeast of the Ratcliffe Observatory, the London area, and towards Kent.
And just to. I live on Dartmoor. It was a drought.
Summer and autumn. And there's the fern, the reservoir.
And what's exposed is the old bridge in fern where the village which was drowned by the reservoir in 1942.
The Clapper Bridge and the road bridge. And that's not been seen since I had the look in the drought of 2010 12, and that did not appear.
So that shows you how much that wasn't a very long period, I don't think.
But the temperatures made the effect of the decreased rainfall that much more severe because it was so warm.
Spring in autumn. Now these have shown the most warming.
This is the pattern.
Right back for 18, 15, 20 year one remains and the annual values in spring and autumn, the three months, autumn, September to November.
Spring is March two to May. And you can see a lot.
Lots of interannual variability, but lots and lots of warming in the last of 30 years or so over one degree.
So the lion's share really of the warming of Central England temperature and the Radcliffe Observatory really has come from spring and autumn.
And the reason for that is not utterly clear.
But as I pointed out, too, in the other seasons, the weather patterns have a very large effect on the temperatures.
So this has not happened in the autumn.
What's tended to happen, I think, is the weather patterns in the autumn and spring have tended to be warm weather patterns.
And that's probably slightly added to the background effect of global warming, though there is no paper actually yet written on that subject.
So, you know, you could use the fact of observatory record with Central England temperature to write a nice paper on that that topic.
Finally, global warming. And this is quite surprising.
In the dotted line is the classical global warming record is a ten year running means, by the way, of land and ocean.
The ocean warmed slower than the land. So in the black,
the black solid line is the global land that's everywhere over land that we can measure
temperature back to the mid-19th century and we can make estimates of uncertainty.
But that's too much to put on there. Superimposed on that is Central England temperature with the ten year running main and the Ratcliffe Observatory.
Now we know the Ratcliffe Observatory has got a bit more warming due to urbanisation.
So just concentrate on Central England temperature and although it fluctuates more because
of weather patterns locally and there were some local effects in the Atlantic as well,
the Atlantic temperatures don't always vary in the same way as the globe.
Nevertheless, if you take out this sort of multidecadal variability,
you'll see that Central England and Ratcliffe Observatory taking out the urbanisation has fluctuated very much the same as the global mean.
So those sceptics that don't believe in global mean temperature can't really believe in the Ratcliffe record either.
On my last slide, I want to congratulate the Richard and his predecessors, Tim, on maintaining this unique long record.
Unfortunately, that some of the other records have not been maintained like Q Observatory and the Met Office slows down.
And then we have 200 years of continuous meteorological observations, and that's Myles Allen,
who's well-known climatologist, and he's got a bottle of something in his hand.
So I imagine he celebrating something, whatever it is.
Thank you very much.