Autumn is on it’s way – the last 8,760 hourly temperatures at Exeter

Figure 1

Ever wondered what a scatter graph of hourly temperatures for a year looks like? The chart above (fig 1) does exactly that for Exeter airport, along with a 24 hour (black) and 7 day centred moving averages to boot. The cool morning temperature of 5.8°C from the airport, reminded me that Autumn is on its way, even though for the first few days of the coming week 1000-500 hPa partial thicknesses will be in excess of 564 dm. The 7 day moving average which peaked in June at close to 20°C, and has been declining erratically since the middle of July.

Figure 2

The sunshine stats may well be a little low for Exeter, with an annual total of just 1414.3 hours, this is because the sunshine record is not 100%. There are occasionally missing values from the SYNOP reports that I can do little about, December 2016 had quite a number, and might explain the odd behaviour of the moving average (fig 2). Even so, the sunny spells that did occur in early April, and in the second half of May are clearly visible, as is the warm and sunny June in both temperature and sunshine graphs.

State of the UK Climate 2016

The Met Office have just released the third edition of their State of the UK Climate for 2016. I always find that this a strange time to publish such a document, why not by the end of January? But once you have taken a look at the 59 page document, you’ll see that it must take a lot of work to put it all together, and I am just being my old curmudgeonly self.

There’s an interesting correction at the foot of the article about CET, which as most of you know is something I like to talk about at length. I find it amazing how people scour the climate datasets to pick out a new extreme, be it high or low, this one’s no exception – decades that span 10 years but don’t start on a year that ends in a zero aren’t what I would call a decade. It’s time to see what the Collins dictionary definition of a decade is:

A decade is a period of ten years, especially one that begins with a year ending in 0, for example 1980 to 1989.

So they are strictly correct, but personally I still like to think of a decade as a period that starts with a year that is divisible by 10 without a remainder, as the Collins dictionary definition suggests it is. Anyway back to the correction, what they were initially said was that the period 2007-2016 was the warmest ‘decade’ in the whole series back to 1659. Obviously they noticed that something was wrong, and said it was incorrect. I wonder why they didn’t just delete the reference in the HTML? I was certainly late on this one and never saw the original.

Just out of interest, here is a centred 10 year moving average of monthly CET values since 1900 (fig 2), and as far as I can see, the warmest decade was the one from 1997 to the end of 2006, when the mean 10 year anomaly for the first time just exceeded +1.0°C, since then, Central England has cooled, until about 2012, when annual anomalies increased sharply again. I think the reason they corrected the original article could have been for a typo, because 2007-2016 and 1997-2006 are just ten years apart. They can always ask me to provide them with graphs, I have a graph of CET values to suit just about any occasion, and the bonus is that I work cheap.

Figure 2

Here for completeness is the full 10 year series of moving averages since 1659 (fig 3).

Figure 3

And finally the infographic that the graphics team have produced to advertise the publication of the 2016 report is a bad idea to my mind. I love a well designed infographics – you only have to look at my blog to see that – and I do realise climate statistics are not the most exciting things to try to visualise, but a clear well constructed table or graph is really all you should need. Most of us have moved on from kindergarten I would have hoped, but they may have been instructed to produce a simple infographic for politicians the like of Michael Gove to understand what’s going on.

Figure 4 – Courtesy of the Met Office

High risk of unprecedented rainfall

Figure 1 – England Wales Precipitation (October – March) 1766 – 2016 – data courtesy of the Met Office

Dr Adam Scaife has been at it at the Met Office again, or more correctly I should say that Dr Vikki Thompson the lead author of the report ‘High risk of unprecedented rainfall in the UK in the current climate‘ has. News of her findings are in the latest Met Office blog, in which she says:-

“Our computer simulations provided one hundred times more data than is available from observed records. Our analysis showed that these events could happen at any time and it’s likely we will see record monthly rainfall in one of our UK regions in the next few years”

According to the article:-

“Analysing these simulated events showed there is a 7% risk of record monthly rainfall in south-east England in any given winter. When other regions of England and Wales are also considered this increases to a 34% chance”

I can’t totally agree with her when she says in the included video that:-

“…older records are now no longer so relevant to the current risk because climate has changed over the past century”

My question to her would be – “why do we know climate has changed?” – the answer to that is because we already have existing rainfall data back to 1910, wouldn’t it then be wise to digitise all the rainfall data that the Victorian’s collected from 1859, and just see how unprecedented (and believable) the rainfall events that their new supercomputer has generated?

Sometimes I think that the NWP programmers have taken over the asylum Met Office, rather than the climatologists taking the lead in these investigations, or perhaps they’ve fused together as one being that does both.

They maybe onto a winner with this one though, because a quick look at the “real” (or as close as we are going to get it) gridded England Wales Precipitation from 1766, and the simple linear trend is definitely upwards and wetter by 22.7% in those 250 years (fig 1). If the total rainfall across the October-March period has increased, then you would logically infer that the number of unprecedented months has also increased.

The article goes onto say:-

The authors have named this novel research method the UNSEEN method to emphasize that this analysis anticipates possible events that have just not yet been seen.

I can’t see a link to the report that they are talking about in the blog, so it maybe that they’ve applied the “unseen method” to that, and we are to rely on the infographic (fig 2) for people with really short attention spans like myself.

Figure 3 – Courtesy of the Met Office

So if Climate change is likely to increase the frequency and magnitude of severe flooding events as many people think, why has rainfall declined, and not increased in the other half of the year? I reckon that April to September precipitation is 13% lower than it was 250 years ago (fig 3). But of course older rainfall records are now no longer as relevant these days, because the climate has changed so much, and we should probably just disregard it.

Figure 4 – England Wales Precipitation (April – September) 1766 – 2016 – data courtesy of the Met Office

What’s the sunniest month of the year?

I thought that I would investigate and find out exactly what climatologically is the sunniest month of the year using monthly sunshine data from the Met Office. The gridded sunshine record only started in 1929, but I’ve been reliably informed by someone in the know at the Met Office, that plans are well advanced to extend this (along with the rainfall and temperature series), back to at least the start of the 20th century, which I applaud, although in my opinion it’s a long way overdue. The add-on to my application looks not only at sunshine, but rainfall and temperature too, and for any region within the United Kingdom. The pie chart I’ve include is for England & Wales (fig 1), and reveals, surprisingly to many I bet, that May is climatologically the sunniest month of the year in 35.2% of years since 1929, followed by June in 31.8% of years, and July in 19.3% of years.

Figure 1 – Data courtesy of the Met office

Also rather surprisingly, it can happen that in some years April is the sunniest month. According to my application that’s occurred five times, in 1945, 1954, 2002, 2007 and 2011, so three times in the last 15 years. There’s always a chance that I’ve made an error let me know if I have.

The sunniest month in the entire England and Wales record was the July of 2006 with 287.6 hours of sunshine (fig 2). The sunniest month in the famous summer of 1976 was also a July with 251.5 hours of sunshine, but ranked only 13th in the list of sunniest months in a year.

Figure 2 – Data courtesy of the Met Office

The sunniest May’s in the UK since 1929

What was the sunniest May in the UK? That of course depends on where you live, so using the regional gridded sunshine data series from the Met Office that started in 1929 here is a map of the sunniest May for each of the nine individual regions, and for the whole series in a horizontal bar chart (fig 1). May is climatologically the sunniest month of the year in the UK, but more of that in an upcoming post, and by the look of it, the May of 1989 was the sunniest in nine of the seventeen regions, including the UK and England and Wales, if the gridded sunshine values are anything to by.

Figure 1 – Data and map courtesy of the Met Office.

The 1989 record certainly is in no danger of being broken in the southeast this year, but it’s certainly could in Northern Ireland and the west of Scotland, where they’ve got off to a flying start (fig 2).

Figure 2

April sunshine totals 1981-2010

Figure 1

The sunniest place on average in the UK in the period between 1981 and 2010 is Shanklin on the Isle of Wight with 201.4 hours. In fact most of the climate stations in the top 17 can be found on the English Channel coast somewhere. On the southwest peninsula the fall off in sunshine the further away from the coast you are looks to be around 10%. The Met Office provide these 1981-2010 average in their DataPoint web service and are not neither straightforward to download or to parse, because they’re all in XML format and come as individual files for almost 300 locations. The things I have to go through for a climate story.

Figure 2

I contacted the Met Office at Jersey yesterday and asked them what their record highest April sunshine total and got this tweet back.

Figure 3

I make their total for the same period 249.5 hours, yesterday they had another 2.5 hours taking them up to 252.0 hours. I’ve tweeted the Met Office at Jersey and asked them to check their total, but so far have had no response. As far as I can see I’ve done the maths correctly, and my old maths teacher Mr Brightmoor I’m sure would have been proud of me. The 1981-2010 average for Jersey is 196.5 hours in April, so that makes the latest anomaly just over 28% above the average.

Figure 4

A little white lie from the Met Office

Quite a lot of things annoy me about the Met Office as regulars readers of this blog will have no doubt picked up over the years. One of the worst traits that they have, is when talking about climate statistics for the UK, they use the following phrase:

“When records began in 1910…”

When you know full well that detailed records existed much earlier than that. What they ought to say, which is much close to the truth, is:

“We’ve only managed to digitize records back as far back as 1910, and even though we hold detailed climate records that go as far back as the early 1850’s, we can’t be bothered to do anything with because we’ve already spent the money on a big new shiny supercomputer.”

There is a classic example of that on their website today concerning the occurrence of frost in the UK during April.

Figure 1 – Courtesy of the Met Office

“Detailed frost recording in the UK began in 1961”. What a shocking admission for the national weather service of a country that was established in 1854. That must mean all of the sterling work done by meteorologists before 1961 was all in vain and a complete waste of time. What happened to all the temperature records between 1854 and 1960? At random, I picked out a copy of the DWR for January 1917 just to see if there were any extreme temperatures reported back then, and unsurprisingly there they were, for thirty-three stations across the British Isles (fig 2). Of course that’s just the tip of the iceberg, because like today, many more climatological returns from stations remain unpublished and go straight into the archives.

Figure 2 – Courtesy of the Met Office ©Crown Copyright

Absolutely no excuse

The Met Office were one of the first big users of computers and still are, here is a list of the computers that they’ve used down through the years (fig 3). I realise that looking forward with NWP model is vital, but so is looking back, and treasuring the climate data that previous generations have made since 1854. But why is it that climate records have always seemed to have been neglected, and climate data limited and inaccessible when there seems to have been no lack of one of the world’s fastest supercomputers at their disposal?

Figure 3 – Courtesy of Wikipedia

The Met Office have the resources, both in terms of staff and computing power to digitize the rainfall, temperature and sunshine records of the past and extend the gridded data series that they already have, back at least 50 years before 1910, but they have chosen to leave that wealth of old climate data untapped, and for the life of me, I just can’t understand why?

April 2011 – warmest on record*

Figure 1 – Image and data courtesy of the Met Office, CRU & Wetterzentrale

April 2011 – warmest on record*

*Or what you can do with a load of climate and weather data

Figure 2 – Data courtesy of the Met Office

It seems that we have incredibly short memories when it comes to weather across the country, well at least I know that I have, and that’s why I never noticed that April 2011 was, and still is the warmest April on record since at least 1659 in Central England (figs 2, 3 & 4). The mean CET temperature for the month was +3.91°C above the 1961-1990 long-term average, and 0.6°C warmer than the second warmest April in the list 2007. I’ve just put together a blog that consists of a number of tables, charts and graphs of climate data for the month that I’ve constructed from data or images that I’ve downloaded from the Internet.

Figure 3  – Data courtesy of the Met Office

Here’s a more detailed of daily temperatures, in what was a very mild Spring in Central England, particularly in March and April (fig 4).

Figure 4 – Data courtesy of the Met Office

The monthly mean 12 UTC temperature anomaly of +5°C sits across northeast France and dominates most of western Europe by its influence (fig 5).

Figure 5  – Data courtesy of NCEP/NOAA

The mean pressure field for the month of April was ideal for warm and dry weather with plenty of sunshine. An anomaly of +6 hPa over the North Sea enabled a cut-off anticyclonic cell over England and Wales, although the weather was more southwesterly in the northwest (figs 6 & 7).

Figure 6 & 7 – Data courtesy of NCEP/NOAA

Here’s a chart of daily rainfall from the EWP series (fig 8), apart from a wet start, the month was predominantly dry in all areas of the UK except the northwest of Scotland.

Figure  8 – Data courtesy of the Met Office

And here are the 12 UTC plotted SYNOP observations for Northolt  in London for each day of that April (fig 9).

Figure 9 – Images courtesy of OGIMET

And finally here are anomaly charts of rainfall, temperature and sunshine for the month courtesy of the Met Office (fig 10). The thing is I can produce maps, charts and graphs easier than I can write the text that glues them all altogether.

Figure 10 – Images courtesy of the Met Office

21st March 2017

These are some plotted climate charts for yesterday across the British Isles and near continent. They include sunshine for yesterday, precipitation [06-06 UTC] and maximum [06-18] and minimum temperatures [18-06]. It’s not particularly exciting I know, but I was just looking at another way of displaying the charts that I generate from how I have done it in the past.

Is the UK getting wetter?

I was just looking through the climate records that the Met Office provide for downloading across the country. I had written an application, as is often the case it was another one of my climate and weather applications that I had sadly neglected to finish off. The Met Office are very frugal when it comes to allowing people to access climate data, and it’s no different with this historic station data series. Take a look at the scanty coverage of monthly climate data they make freely available (fig 1). The monthly climate data is limited to just 37 stations across the entire UK, three of those stations have closed. Here in the entire southwest of England, there are just three long time series available to download, Camborne, Chivenor and Yeovilton. No climate data available for St Mary’s, Plymouth, Exeter or Dunkeswell, even with the headquarters in Exeter.

Not that you get a great deal of climate information in the monthly data that they do release (fig 2). There is no information regarding the frequency of wind speed, direction or highest gust during the month, no MSLP information, no frequency of visibilities, no days of fog, thunder, gale, ground frost, hail, sleet or snow, just the barest of bones – why give it away when someone will pay you for it?

Figure 2

Following on from the article that I wrote about Climate changes in the UK since 1910, I thought that I would use this monthly data to see if I could find any long-term trends in annual precipitation from some of the 28 available climate records from stations across the country. I start with Sheffield, which has a long climate record that started in 1883 (fig 3). In my application I decided to display three charts for precipitation, the top one displays a 12 month rolling accumulation for the entire record. With the top graph you can select a period (yellow overlay), and display that period as a bar chart of monthly totals and monthly anomalies in the lower two charts.

As far as I can see using a simple linear trend in the accumulation series, there has been a +11.5% increase in annual precipitation in the last 133 years in the City.

Figure 3

Oxford has an even longer record that stretches back to 1853, but the increase there is only +2.6% in the 163 year record (fig 4).

Figure 4

Armagh has a rainfall record that also stretches back to 1853, but there there’s been a -1.4% decrease in annual rainfall (fig 5).

Figure 5

The Wick record which started in 1914 shows an increase in annual precipitation of +7.3% (fig 6).

Figure 6

The Stornoway record that started in 1874 shows a decrease in annual precipitation of -1.7% (fig 7).

Figure 7

It’s a bit difficult to find a climate station with a long climate record in the south so Heathrow which started in 1948 will have to do. It shows an increase in annual precipitation of +3.7% (fig 8).

Figure 8

These results obviously need plotting on a map if you are to try to make any sense from them, which I will get round to, but for now these results will have to do. I am surprised to find that a couple of stations did come up with drier trends, it could of course be down to the fact that I haven’t used a fixed time period for the linear trends.

To finish, I’ll just display the monthly England and Wales precipitation series that’s also free to download from the Met Office (fig 9). That series started in 1766, and shows a +5.3% increase in annual precipitation in the last 250 years across England and Wales. So I would say that it has been slowly getting wetter, certainly in England and Wales, but I need to do a much fuller analysis than this very limited quick look. There is one thing that I have found out conclusively though with this bit of programming, and that is rainfall records extend much further back than 1910!

Figure 9

Let me know if you spot any statistical howlers in this piece.